Thomas Buder

Dependency of intraocular pressure elevation and glaucomatous changes in DBA/2J and DBA/2J-Rj mice.

PURPOSE In this study parameters relevant for glaucoma in DBA/2J (D2J) mice were compared with those in age-matched DBA/2J-Rj (D2Rj) mice, to challenge the postulated role of D2J mice as a model for secondary high-tension glaucoma. METHODS Genotyping for three known short nucleotide polymorphisms (SNPs) in the Tyrp1 gene and the Gpnmb gene by MALDI-TOF-MS and immunohistochemical staining for Gpnmb was performed in D2J and D2Rj mice. Twelve C57Bl/6 (B6), 8 D2Rj, and 11 D2J mice between 1 and 4 months of age were screened qualitatively and quantitatively for morphologic differences within the anterior eye segment. The IOP progression of 25 D2Rj and 18 D2J mice were investigated between 4 to 10.5 months after birth. At the end of this study, in 10 randomly selected individuals of each D2J and D2Rj cohort, correlation of IOP progression and optic nerve damage were determined in each eye. RESULTS D2J and D2Rj strains were homozygous for both Tyrp 1 amino acid substitutions, so far only described in D2J mice. The Gpnmb(R150X) point mutation present in D2J mice was not detected in D2Rj. Accordingly, immunoreactivity (IR) for Gpnmb was present only in D2Rj and B6 eyes, but not in D2J. Compared with B6, both DBA/2 mice (D2) showed a significantly narrowed chamber angle caused by an anteriorly displaced ciliary body. IOP measurements showed an average IOP of approximately 14 mm Hg between age 4 and 7 months in D2Rj, which decreased to approximately 11 mm Hg in the period from 8 to 10.5 months. In D2J the average IOP showed a steady increase in the observed period from 4 to 10.5 months (from 8.65 to 15.58 mm Hg). Individuals with IOP peaks up to 30 mm Hg were detected in D2Rj, but none of these mice showed signs of an optic neuropathy after 10.5 months. In contrast, 30% of the investigated D2J mice at the age of 10.5 months showed a severe optic neuropathy. Individual data analyses, however, showed no significant correlation between elevated IOP and glaucomatous changes within the D2J population. CONCLUSIONS Individual correlations of IOP course with axon loss in the single eyes confirmed that in D2J mice, hypertension is not the only causative factor in glaucomatous optic neuropathy. For further investigations on the pathogenesis of glaucoma in D2J mice, the D2Rj strain without a Gpnmb(R150X) mutation and without glaucomatous changes, but with individual IOP elevation, can be used as an interstrain control for D2J.

Properties of maltose-inducible α-glucosidase MalL (sucrase-isomaltase-maltase) in Bacillus subtilis : evidence for its contribution to maltodextrin utilization

Recently, we identified the maltose inducible alpha-glucosidase MalL of Bacillus subtilis. The malL gene encodes a 561-residue protein with amino acid identities to several alpha-glucosidases and is located in a nine-gene spanning gene cluster, which is presumably organized in an operon. MalL was overproduced, purified, and its enzymatic characteristics were described in more detail. This characterization of the enzyme showed a protein stable up to 37 degrees C after temperature treatment for 15 min and exhibiting an optimal reaction temperature of 42 degrees C. Various disaccharides such as sucrose, maltose, and isomaltose were hydrolyzed with different efficiencies. MalL also hydrolyzes longer maltodextrins from maltotriose up to maltohexaose, but not maltoheptaose, palatinose, isomaltotriose, or isomaltotetraose. MalL expression is subject to both maltose induction and carbon catabolite repression. In this article, we present data demonstrating that induction of MalL expression also occurs when starch, amylose, or glycogen are present in the growth medium. The hydrolysis of these substrates by alpha-amylase presumably leads to products which, when taken up into the cytoplasm, trigger the initiation of maltose operon transcription. Furthermore, MalL expression varies temporally, showing a second induction in the stationary growth phase.

Age- and Sex-Dependent Changes of Intra-articular Cortical and Trabecular Bone Structure and the Effects of Rheumatoid Arthritis.

The objective of this cross‐sectional study was to define normal sex‐ and age‐dependent values of intra‐articular bone mass and microstructures in the metacarpal heads of healthy individuals by high‐resolution peripheral quantitative computed tomography (HR‐pQCT) and test the effect of rheumatoid arthritis (RA) on these parameters. Human cadaveric metacarpal heads were used to exactly define intra‐articular bone. Healthy individuals of different sex and age categories and RA patients with similar age and sex distribution received HR‐pQCT scans of the second metacarpal head and the radius. Total, cortical, and trabecular bone densities as well as microstructural parameters were compared between 1) the different ages and sexes in healthy individuals; 2) between metacarpal heads and the radius; and 3) between healthy individuals and RA patients. The cadaveric study allowed exact definition of the intra‐articular (intracapsular) bone margins. These data were applied in measuring intra‐articular and radial bone parameters in 214 women and men (108 healthy individuals, 106 RA patients). Correlations between intra‐articular and radial bone parameters were good (r = 0.51 to 0.62, p < 0.001). In contrast to radial bone, intra‐articular bone remained stable until age 60 years (between 297 and 312 mg HA/cm3) but decreased significantly (p < 0.001) in women thereafter (237.5 ± 44.3) with loss of both cortical and trabecular bone. Similarly, RA patients showed significant (p < 0.001) loss of intra‐articular total (263.0 ± 44.8), trabecular (171.2 ± 35.6), and cortical bone (610.2 ± 62.0) compared with sex‐ and age‐adjusted controls. Standard sex‐ and age‐dependent values for physiological intra‐articular bone were defined. Postmenopausal state and RA led to significant decrease of intra‐articular bone.

Early Changes of the Cortical Micro-Channel System in the Bare Area of the Joints of Patients With Rheumatoid Arthritis: CoMiC SYSTEM CHANGES IN EARLY RA

To characterize the specific structural properties of the erosion‐prone bare area of the human joint, and to search for early microstructural changes in this region during rheumatoid arthritis (RA).Objective: To characterize the specific structural properties of the erosion-prone bare area of the human joint and to search for early microstructural changes in this region during rheumatoid arthritis Methods: An initial cadaveric study was used for exact localization of the bare area of the metacarpal heads, detection of cortical micro-channels (CoMiCs) in this region by high-resolution peripheral computed tomography (HR-pQCT) and, after anatomical dissection, their validation by micro-computed tomography (μCT). In the second part, number and distribution of CoMiCs were analyzed in 105 healthy individuals and 107 RA patients with similar sex and age distribution. Results: HR-pQCT investigation combined with adaptive thresholding allowed detection of CoMiCs in the bare area of cadaveric joints. Their existence in the bare area was additionally validated by μCT. In healthy individuals, the number of CoMiCs increased with age. RA patients showed significantly (p<0.001) more CoMiCs (112.9±54.7/joint) than healthy individuals (75.2±41.9/joint) with 20-49 years old RA patients exhibiting similar CoMiC numbers as observed in over 65 year old healthy individuals. Importantly, CoMiCs were found in RA patients already very early in their disease course with enrichment in the erosion-prone radial side of the joint. Conclusion: CoMiCs represent a new form of structural change in the joints of patients with RA. While CoMiCs increase with age, RA patients develop such changes much earlier in life and already at the onset of the disease. CoMiCs therefore represent an interesting new opportunity to assess structural changes in RA. This article is protected by copyright. All rights reserved.

Surgical Fixation of Sternal Fractures: Preoperative Planning and a Safe Surgical Technique Using Locked Titanium Plates and Depth Limited Drilling

Different ways to stabilize a sternal fracture are described in literature. Respecting different mechanisms of trauma such as the direct impact to the anterior chest wall or the flexion-compression injury of the trunk, there is a need to retain each sternal fragment in the correct position while neutralizing shearing forces to the sternum. Anterior sternal plating provides the best stability and is therefore increasingly used in most cases. However, many surgeons are reluctant to perform sternal osteosynthesis due to possible complications such as difficulties in preoperative planning, severe injuries to mediastinal organs, or failure of the performed method. This manuscript describes one possible safe way to stabilize different types of sternal fractures in a step by step guidance for anterior sternal plating using low profile locking titanium plates. Before surgical treatment, a detailed survey of the patient and a three dimensional reconstructed computed tomography is taken out to get detailed information of the fracture’s morphology. The surgical approach is usually a midline incision. Its position can be described by measuring the distance from upper sternal edge to the fracture and its length can be approximated by the summation of 60 mm for the basis incision, the thickness of presternal soft tissue and the greatest distance between the fragments in case of multiple fractures. Performing subperiosteal dissection along the sternum while reducing the fracture, using depth limited drilling, and fixing the plates prevents injuries to mediastinal organs and vessels. Transverse fractures and oblique fractures at the corpus sterni are plated longitudinally, whereas oblique fractures of manubrium, sternocostal separation and any longitudinally fracture needs to be stabilized by a transverse plate from rib to sternum to rib. Usually the high convenience of a patient is seen during follow up as well as a precise reconstruction of the sternal morphology.

Rheumatoid arthritis is characterized by early changes of the cortical micro-channel (CoMiC) system in the bare area of the joints

To characterize the specific structural properties of the erosion‐prone bare area of the human joint, and to search for early microstructural changes in this region during rheumatoid arthritis (RA).Objective: To characterize the specific structural properties of the erosion-prone bare area of the human joint and to search for early microstructural changes in this region during rheumatoid arthritis Methods: An initial cadaveric study was used for exact localization of the bare area of the metacarpal heads, detection of cortical micro-channels (CoMiCs) in this region by high-resolution peripheral computed tomography (HR-pQCT) and, after anatomical dissection, their validation by micro-computed tomography (μCT). In the second part, number and distribution of CoMiCs were analyzed in 105 healthy individuals and 107 RA patients with similar sex and age distribution. Results: HR-pQCT investigation combined with adaptive thresholding allowed detection of CoMiCs in the bare area of cadaveric joints. Their existence in the bare area was additionally validated by μCT. In healthy individuals, the number of CoMiCs increased with age. RA patients showed significantly (p<0.001) more CoMiCs (112.9±54.7/joint) than healthy individuals (75.2±41.9/joint) with 20-49 years old RA patients exhibiting similar CoMiC numbers as observed in over 65 year old healthy individuals. Importantly, CoMiCs were found in RA patients already very early in their disease course with enrichment in the erosion-prone radial side of the joint. Conclusion: CoMiCs represent a new form of structural change in the joints of patients with RA. While CoMiCs increase with age, RA patients develop such changes much earlier in life and already at the onset of the disease. CoMiCs therefore represent an interesting new opportunity to assess structural changes in RA. This article is protected by copyright. All rights reserved.

Comparative studies of different types of osteosynthesis on the human corpse preparation in bilateral antero-lateral flail chest

INTRODUCTION Bilateral flail chest injuries are challenging in treatment and comparatively often require an operative stabilization of the anterior chest wall to re-establish normal physiological conditions of the chest wall in shape and statics. Various procedures have been described which are technically sophisticated for the surgeon. Consequently there is an increasing interest in potentials of operative care and their effectiveness on the anterolateral chest wall. MATERIALS AND METHODS 12 Human cadavers were prepared and the natural Sternum Position (NP) was marked. A digital probe was fixed to the sternum at the height of the 4th intercostal space in order to measure and compare the stability of the thorax. Readings were taken of the sternal displacement at 1-5cm sagittal distance from NP in starting conditions and from every combination of materials. Serial osteotomies were performed on 2 locations on ribs 2-8 to induce bilateral flail chest. Afterwards the stabilization was achieved with different implants: RESULTS: The osteotomies lead to a subsidence of the sternum occurred to almost 75 mm from NP which corresponds to a maximal unstable situation. The unstable chest wall showed substantially more stabilization through the use of locking plates. Our materialcombinations showed a stability of up to 60% of normal. The more ribs were treated osteosynthetically, the higher the stability of the chest wall. DISCUSSION AND CONCLUSIONS Locking plate fixation offers anatomically realignment of the ribs whereas metal strut support only lifts up the chest wall, but could not provide realignment of the dislocated ribs.

SAT0628 Increase of cortical micro-channels (COMICS) as a new feature of structural damage in paients with rheumatoid arthritis

Background Bone damage in rheumatoid arthritis (RA) typically emerges at certain anatomical hotspots corresponding to the so-called “bare area”, an intra-articular region between the cartilage and the insertion site of the joint capsule (1,2). We hypothesized that this region exhibits certain micro-anatomical properties, which facilitates the emergence of bone erosions. Objectives To find the micro-structural correlate of the origin of bone erosions in the bare area of the human joint Methods Bare areas of human joints were analyzed for early microstructural changes by in-vivo high-resolution peripheral computed tomography (HR-pQCT). First, bare areas were exactly defined by scanning 6 cadaveric hands for localization of the bare area in the human metacarpal head. Bone lesions found in the cadaveric hand by HR-pQCT were additionally by super-resolution ex vivo micro-CT (μCT40). Then, number and distribution of the type of bare area bone lesion found in cadaveric study were analyzed in a cohort of 105 healthy individuals and 107 anti-citrullinated peptide (ACPA) positive RA patients with similar sex and age distribution. Results HR-pQCT combined with adaptive thresholding allowed the definition of a new type of bone lesions in the bare areas of the human joint termed “COMIC” standing for “cortical micro-channel”. Their existence in the bare area was additionally validated by microCT (Figure 1). RA patients showed significantly (p<0.001) more CoMiCs (112.9±54.7/joint) than healthy individuals (75.2±41.9/joint) with 20–49 years old RA patients exhibiting similar CoMiC numbers as observed in over 65 year old healthy individuals. Importantly, CoMiCs were found in RA patients already very early in their disease course with enrichment in the erosion-prone radial side of the joint. Conclusions CoMiCs represent a new structural feature of the joint, which is characteristic for the bone of the bare area. COMICS at low level are also found in young healthy individuals but they significantly increase with age and particularly with RA. COMICs develop much earlier and much more pronounced in RA patients than in healthy individuals and therefore represent an interesting new early indicator for erosion development in ACPA positive RA patients. References Stach CM, Bauerle M, Englbrecht M, Kronke G, Engelke K, Manger B, et al. Periarticular bone structure in rheumatoid arthritis patients and healthy individuals assessed by high-resolution computed tomography. Arthritis & Rheumatism. 2010;62(2):330–9. Simon D, Kleyer A, Stemmler F, Simon C, Berlin A, Hueber AJ,Haschka J, Renner N, Figueiredo C, Neuhuber W, Buder T, Englbrecht M, Rech J, Engelke K, Schett G. Age- and Sex-Dependent Changes of Intra-articular Cortical and Trabecular Bone Structure and the Effects of Rheumatoid Arthritis. J Bone Miner Res. 2016 Oct 27. doi: 10.1002/jbmr.3025. [Epub ahead of print]. Disclosure of Interest None declared

Anatomy and Blood Supply of the Sternum

The sternum is a sword-shaped flat bone about 15–17 cm long in the adult (◙ Fig. 2.1) (Putz and Muller-Gerbi Benninghoff 2003; Williams and Warwick 1980). Its cranial part, the manubrium, connects to the corpus by a synchondrosis in 90% of adults; in the remaining 10% there is a bony fusion (synostosis).

OP0220 Intraarticular Micro Channels of MCP Joints Increase During Development of Rheumatoid Arthritis

Background High Resolution peripheral Quantitative Computed Tomography (HR- pQCT) allows to detect very small cortical breaks, so called “microchannels” in the periarticular bone. These structures resemble an interaction between the bone marrow and synovial compartment potentially allowing communication of inflammation between these two compartments. Objectives To quantify micro-channels in healthy individuals, ACPA-positive individuals and early rheumatoid arthritis (RA) patients. Methods HR-pQCT (XtremeCT, Scanco, Switzerland) scans of healthy subjects, ACPA positive subjects without RA and ACPA positive early RA patients were assessed. Transversal, sagittal and coronal planes of the 2nd metacarpophalangeal (MCP) head were scored for microchannels. Analysis was performed by two independent and blinded readers. To search for a potential function these cortical microchannels we performed HR-pQCT measurements of cadaveric hands (n=6, Body Donation Program of the Institute of Anatomy, University Erlangen-Nuremberg) with contrast enhancement to display vessels. After defrosting at room temperature for 24h hours, the radial and ulnar artery was dissected and contrast agent (Imeron 350 Iod/ml, Bracco Imaging, Germany) was injected in both arteries followed by HR-pQCT measurement. The study was approved by the local ethics committee. Results A total of 61 healthy controls (29 females; 32 males), 21 ACPA positive subjects (17 females; 4 males), 35 ACPA positive RA (25 females; 10 males; disease duration 0.66 yrs) were evaluated. Cortical channels were detected in all subjects with distinct localization (Fig. 1a). Most lesions were located intra-articularly at the palmar and radial side of the MCP 2 head. We found a significant difference (p=0.001) in the numbers of microchannels between the three groups with higher numbers in the early RA group compared to the healthy controls (Fig 1b). Using contrast enhanced HR-pQCT images of human cadaver hands we were able to display intracortical and medullar vessels with a size as low as 0.15 mm diameter (Fig. 2a/b). In addition, vascular trees around the wrist and MCP joints could be visualized after 3D segmentation (Fig. 2c). Despite good vascular visualization no contrast enhancement was observed in the intraarticular region of the above described channels. Conclusions Micro-channels in the periarticular bone increase during the development of RA. Until now the function of micro channels is still unclear. If cortical channels reflect breaks, vessels from “inside-out”, cartilage anchors or nutritive channels still needs to be determined. Disclosure of Interest None declared