Quantitative Scaling of Magnetic Avalanches.

We provide the first quantitative comparison between Barkhausen noise experiments and recent predictions from the theory of avalanches for pinned interfaces, both in and beyond mean field. We study different classes of soft magnetic materials, including polycrystals and amorphous samples-which are characterized by long-range and short-range elasticity, respectively-both for thick and thin samples, i.e., with and without eddy currents. The temporal avalanche shape at fixed size as well as observables related to the joint distribution of sizes and durations are analyzed in detail. Both long-range and short-range samples with no eddy currents are fitted extremely well by the theoretical predictions. In particular, the short-range samples provide the first reliable test of the theory beyond mean field. The thick samples show systematic deviations from the scaling theory, providing unambiguous signatures for the presence of eddy currents.

Medical Students' Knowledge About Brain Death: A South African Contribution.

BACKGROUND: Incorporating transplantation into undergraduate medical curricula can improve organ procurement rates. Intricacies related to the assessment of donor suitability, the clinical diagnosis of brain death, and relevant legal processes are key challenges for the newly qualified doctor. The aim of this study was to describe and analyze knowledge of medical students regarding the various aspects dealing with the diagnosis of brain death, with a view to designing an undergraduate training module. METHODS: A previously validated, self-administered, 26-item questionnaire was distributed to all medical students at the University of Cape Town. General data included age, sex, year of study, and career interests. Knowledge-specific questions explored the suitability of potential organ donors (8 items), the clinical diagnosis of brain death (7 items), and legal factors (11 items) thereof. Descriptive statistical methods were then used to analyze the data. RESULTS: There were 346 participants; 217 (63%) were pre-clinical students and 29 (8%) carried an organ donor card. The mean and median scores for the 26 items were both 12 (range, 0-25). Mean scores increased steadily with years of medical education: from 8 in the first year of study, 10 in the second year, and 17 in the final year. Demographics, year of study, organ donor status, and an interest in a surgical career did not influence knowledge levels (P > .05). CONCLUSIONS: Medical students have limited knowledge about brain death and identification of potential organ donors. This confirms the need for an educational intervention early in the medical curriculum.

[Trabeculectomy in uveitis associated with juvenile idiopathic arthritis: long-term results in pediatric secondary glaucoma]. / Trabekulektomie bei juveniler idiopathischer Arthritis-assoziierter Uveitis: Langzeitergebnisse beim kindlichen Sekundärglaukom.

BACKGROUND: Secondary uveitic glaucoma in children can only be controlled in many cases by surgery. The aim of this study was to evaluate the outcome of trabeculectomy (TE) with administration of mitomycin C in children with secondary uveitis associated with juvenile idiopathic arthritis (JIA). MATERIALS AND METHODS: This study was a retrospective chart review of 21 children with uveitic glaucoma who underwent TE with administration of mitomycin C including analysis of complications, further interventions, additional surgical procedures to control intraocular pressure (IOP) and of the success rates after a mean follow-up of 5 years. RESULTS: Defining success as an IOP ≤ 15 mmHg, the surgical success rate after TE was 55 % after 1 year and 38 % after 5 years but 43 % of the children required further IOP controlling operations in the long-term follow-up. An IOP ≤ 15 mmHg was observed in 70 % of the children after 1 year and in 62 % after 5 years. In regard to the overall success (with topical antiglaucomatous medication) the success rate increased to 71.4 % after 5 years. CONCLUSIONS: The results show that TE is a suitable surgical procedure to control IOP in secondary uveitic glaucoma of JIA patients. In the long-term follow up additional postoperative adjustments are necessary to control the IOP.

Intercellular transport of Oct4 in mammalian cells: a basic principle to expand a stem cell niche?

BACKGROUND: The octamer-binding transcription factor 4 (Oct4) was originally described as a marker of embryonic stem cells. Recently, the role of Oct4 as a key regulator in pluripotency was shown by its ability to reprogram somatic cells in vitro, either alone or in concert with other factors. While artificial induction of pluripotency using transcription factors is possible in mammalian cell culture, it remains unknown whether a potential natural transfer mechanism might be of functional relevance in vivo. The stem cell based regeneration of deer antlers is a unique model for rapid and complete tissue regeneration in mammals and therefore most suitable to study such mechanisms. Here, the transfer of pluripotency factors from resident stem cell niche cells to differentiated cells could recruit more stem cells and start rapid tissue regeneration. METHODOLOGY/PRINCIPAL FINDINGS: We report on the ability of STRO-1(+) deer antlerogenic mesenchymal stem cells (DaMSCs) to transport Oct4 via direct cell-to-cell connections. Upon cultivation in stem cell expansion medium, we observed nuclear Oct4 expression in nearly all cells. A number of these cells exhibit Oct4 expression not only in the nucleus, but also with perinuclear localisation and within far-ranging intercellular connections. Furthermore, many cells showed intercellular connections containing both F-actin and α-tubulin and through which transport could be observed. To proof that intercellular Oct4-transfer has functional consequences in recipient cells we used a co-culture approach with STRO-1(+) DaMSCs and a murine embryonic fibroblast indicator cell line (Oct4-GFP MEF). In this cell line a reporter gene (GFP) under the control of an Oct4 responsive element is only expressed in the presence of Oct4. GFP expression in Oct4-GFP cells started after 24 hours of co-culture providing evidence of Oct4 transfer from STRO-1(+) DaMSCs to Oct4-GFP MEF target cells. CONCLUSIONS: Our findings indicate a possible mechanism for the expansion of a resident stem cell niche by induction of pluripotency in surrounding non-niche cells via transfer of transcription factors through intercellular connections. This provides a new approach to explain the rapid annual antler regrowth.

Localization and characterization of STRO-1 cells in the deer pedicle and regenerating antler.

The annual regeneration of deer antlers is a unique developmental event in mammals, which as a rule possess only a very limited capacity to regenerate lost appendages. Studying antler regeneration can therefore provide a deeper insight into the mechanisms that prevent limb regeneration in humans and other mammals, and, with regard to medical treatments, may possibly even show ways how to overcome these limitations. Traditionally, antler regeneration has been characterized as a process involving the formation of a blastema from de-differentiated cells. More recently it has, however, been hypothesized that antler regeneration is a stem cell-based process. Thus far, direct evidence for the presence of stem cells in primary or regenerating antlers was lacking. Here we demonstrate the presence of cells positive for the mesenchymal stem cell marker STRO-1 in the chondrogenic growth zone and the perivascular tissue of the cartilaginous zone in primary and regenerating antlers as well as in the pedicle of fallow deer (Dama dama). In addition, cells positive for the stem cell/progenitor cell markers STRO-1, CD133 and CD271 (LNGFR) were isolated from the growth zones of regenerating fallow deer antlers as well as the pedicle periosteum and cultivated for extended periods of time. We found evidence that STRO-1(+) cells isolated from the different locations are able to differentiate in vitro along the osteogenic and adipogenic lineages. Our results support the view that the annual process of antler regeneration might depend on the periodic activation of mesenchymal progenitor cells located in the pedicle periosteum. The findings of the present study indicate that not only limited tissue regeneration, but also extensive appendage regeneration in a postnatal mammal can occur as a stem cell-based process.

[Evaluation of the postoperative clinical results of repositioning isolated zygomatic fractures]. / Beurteilung des postoperativen klinischen Repositionsergebnisses isolierter Jochbeinfrakturen.

This retrospective study included 148 patients who were evaluated for postoperative long-term results after osteosynthesis of isolated zygoma fractures. The influence of open reposition of the zygomaticoalveolar crest to middle face symmetry was evaluated quantitatively with a zygometer. In dependence on operative management patients were divided into two groups: In group I zygomaticofrontal suture (1-point-fixation) and infra-orbital rim were exposed (2-point-fixation), followed by osteosynthesis. In group II additional exposure of zygomaticoalveolar crest was performed and if required osteosynthesis was performed (3-point-fixation). For osteosynthetic reconstruction of isolated zygoma fractures the only 2-point-fixation is usually enough to achieve lateral middle face symmetry. In all cases zygomaticofrontal suture and alternatively infra-orbital rim or respectively zygomaticoalveolar crest should be supplied osteosynthetically. A further 3-point-fixation is indicated only in exceptional cases--for example comminuted fractures of lateral middle face columns. For an exact anatomical reposition of zygoma fractures the exposition and possible osteosynthesis of zygomaticoalveolar crest is recommended.

[Biomechanical examinations of the efficacy of wrist guards in inline skating]. / Biomechanische Untersuchungen zur Effektivität von Handgelenksprotektoren für das Inline-Skating.

INTRODUCTION: Fractures of the wrist and forearm are the most frequent injuries in Inline-Skating. Clinical experience has shown that these injuries can be prevented the use of wrist protectors. But various authors have shown that fractures can also occur despite the use of wrist protectors. Aim of this study was to examine different wrist protectors in a biomechanical set up. METHOD: A standardized trauma was simulated using an artificial hand with a certain weight. The forces with or without protective devices have been recorded by a force moment sensor. The results of different protectors have been compared. RESULTS: A mean force of 956 N was measured without the use of a protective device. With the application of a wrist protector these forces were reduced between 4 and 20 %. The best values have been reached with models with a strong base plate. CONCLUSIONS: The results of the present study may explain the clinical observation that wrist and forearm fractures can occur despite the use of a wrist guard. The protective effect of a wrist protector depends highly on the model that is used.

[Evaluation of B-scan ultrasound, 3-D ultrasound, roentgen diagnosis and sinus endoscopy in follow-up assessment of the maxillary sinus after sinus floor elevation]. / Evaluation der B-Scan-Sonographie, 3D-Sonographie, Röntgendiagnostik und Sinuskopie zur Kontrolle der Kieferhöhle nach Sinusbodenelevation.

PROBLEM: The aim of this study was to determine which technique--B-scan sonography, 3D sonography, X-ray, or endoscopy--is the most effective for diagnosis in changes of the maxillary sinus after sinus lift and simultaneous augmentation. MATERIAL AND METHODS: In 33 patients the maxillary sinus was examined before sinus lift, 1 week and 6 months postoperatively with a 7.5-MHz linear scanner and 3D sonography. At the same time, the sonographic results were compared with the X-ray as well as the endoscopic results. Endoscopy of the maxillary sinus was only applied during the sinus lift operation and the abutment operation after 6 months. RESULTS: A total of 56 operations of sinus lift and simultaneous augmentation with autogenous bone were carried out. Preoperatively, there where no pathological findings detectable in the maxillary sinus. One week postoperatively, the X-rays as well as the sonographic images revealed thickening of the mucosa in 40 maxillary sinuses. After the healing period of 6 months, polyposa was still detected in three cases sonographically, in the radiographic follow-up as well as endoscopically. The sonographic 3D imaging of the maxillary sinus improved the spatial visualization of postoperative changes in the maxillary sinus and the reliability of the diagnosis. CONCLUSION: Due to the lack of radiation, the cost effectiveness, and its reproducibility, sonography is suitable as a primary screening technique in recall. In cases of normal sonographic findings but clinical symptoms, CT, MRT, and endoscopy should be performed to exclude pathological processes of the posterior maxillary sinus.

Tissue expansion using osmotically active hydrogel systems for direct closure of the donor defect of the radial forearm flap.

Although widely used, the radial forearm flap has been criticized for the poor quality of its donor site. Attempts to avoid donor-site problems have concentrated on the elaboration of the split-thickness and full-thickness skin graft methods of reconstruction. Skin grafts frequently fail over the flexor carpi radialis tendon, leading to chronic skin breakdown or, at best, tendon adhesion. Tissue expansion appears to be a good alternative that allows the use of local tissues to ultimately improve the forearm donor-site appearance. To avoid the disadvantages of traditional silicone balloon expanders (such as pressure peaks, infection, the valve at a distance from the expander, postoperative fillings), an osmotically active system was used. In an 18-month prospective study, 10 osmotically active hydrogel tissue expanders were placed on the forearms of 10 patients. The radial forearm flap was performed for intraoral reconstruction after surgical resection of oral cavity malignancies. The study showed that, in nine out of 10 patients, the expanded skin achieved was sufficient to cover the donor site after raising the forearm flap. Additionally, the expansion-related swelling pressure was well tolerated by the patients, the cosmetic results were very satisfactory, and the incidence of complications was very low. By using osmotically active hydrogel tissue expanders, there is no postoperative filling and no risk of complications arising from defective balloon expanders, filling valves, or missing ports.

Renormalization of pinned elastic systems: how does it work beyond one loop?

We study the field theories for pinned elastic systems at equilibrium and at depinning. Their beta functions differ to two loops by novel "anomalous" terms. At equilibrium we find a roughness zeta = 0.208 298 04 epsilon + 0.006 858 epsilon(2) (random bond), zeta = epsilon/3 (random field). At depinning we prove two-loop renormalizability and that random field attracts shorter range disorder. We find zeta = epsilon/3(1 + 0.143 31 epsilon), epsilon = 4 - d, in violation of the conjecture zeta = epsilon/3, solving the discrepancy with simulations. For long range elasticity zeta = epsilon/3(1 + 0.397 35 epsilon), epsilon = 2 - d, much closer to the experimental value (approximately 0.5 both for liquid helium contact line depinning and slow crack fronts) than the standard prediction 1/3.

Biomaterial properties and biocompatibility in cell culture of a novel self-inflating hydrogel tissue expander.

The aim of this study was to investigate the swelling properties and the biocompatibility of a novel tissue expander material. The self-inflating material is a hydrogel consisting of a modified copolymer of methylmethacrylate and N-vinyl-2-pyrrolidone, which takes up water by osmosis. To increase the swelling volume, the primarily neutral gel material was modified by converting it into an ionized gel. To study the swelling and pressure behavior of the material, the anhydrous gel cylinders were equilibrated in distilled water, saline, and sugar solutions. The biocompatibility was investigated in cell culture. We tested the hydrogel eluate after swelling for cytotoxicity and mutagenicity using the cell lines MRC-5 and P3X63 Ag8 653 (Ag8). Furthermore, particles of the material were added to cell cultures to induce foreign body reactions and to verify its influence on monocyte differentiation. The material has a swelling capacity (Q = maximum swelling volume/anhydrous volume) of 5 to 50 depending on the degree of ionization of the polymer network. In this study, two polymer modifications with a swelling equilibrium of Q = 11.1 and 30 in water were tested. The swelling ratio also depends on concentration and ion content of the equilibration medium. The highest swelling capacity was found in water, the lowest in Ringer's solution. The swelling of the anhydrous material with the swelling capacity of Q = 11.1 fits best the average purpose of material properties for tissue expansion and generates a maximal hydrostatic pressure of approximately 235 mmHg. Effects on cell proliferation were detected only at the highest eluate concentration tested (i.e., eluate: culture medium = 1:1), which was far beyond physiological values, whereas mutagenicity was absent. Monocytes neither migrated nor tightly attached to the hydrogel. They neither phagocytose the material nor did they show any sign of a foreign body reaction, e.g., formation of multinucleated giant cells or monocyte proliferation. In the presence of hydrogel material, the differentiation processes of monocytes to macrophages or dendritic cells, respectively, were found to be undisturbed. From these results, we conclude that there is a high biocompatibility of the expander material, which may be a favorable and interesting candidate for further clinical applications.

Alkaline phosphatase expression during monocyte differentiation. Overlapping markers as a link between monocytic cells, dendritic cells, osteoclasts and osteoblasts.

Human monocytes (Mo) in culture can be differentiated into macrophages (M phi), dendritic cells (DC) and osteoclasts. In addition, we have established a Mo-derived in vitro granuloma model which here was compared with ex-vivo isolated foreign body granuloma cells. In these models overlapping phenotypes developed between monocyte-derived dendritic cells (MoDC), osteoclasts, M phi, and osteoblasts. In Mo cultures granulomas were induced by immobilized particulate material. AP activity (osteoblast marker) was found to be co-expressed with cytoplasmic tartrate resistant acid phosphatase (TRAP) as a marker of osteoclasts. While proliferating, the number of AP+ cells decreased, being replaced by cells co-expressing the osteoclast markers vitronectin receptor (VNR) and TRAP. Coexpression of the Mo/M phi marker CD68 with AP or VNR confirmed the monocytic origin of the cells. When Mo were treated with interleukin-4 (IL-4), the number of AP+ cells markedly increased and remained stably expressed over 12 days. In explants from ex vivo granulomas obtained from endoprosthetic revisions the major cell type was the AP+ cell co-expressing CD68. The bone-specific alkaline phosphatase (BAP) as a marker of osteoblasts was detected by FACS analysis in the ex vivo granuloma cells. By RT-PCR the mRNA for osteocalcin, which is a highly specific marker for osteoblasts, was detected. From our results we conclude an ontogenetic relationship between macrophages, DC and osteoclasts. Furthermore, the data suggest a transdifferentiation between Mo and osteoblasts.

Automatic and strategic processing of threat cues in patients with chronic pain: a modified stroop evaluation.

OBJECTIVE: The goal of this study was to clarify whether patients with chronic pain selectively attend to syndrome-specific (i.e., pain-related) information and, if so, to determine whether this occurs at the conscious (i.e., strategic) or unconscious (i.e., automatic) level. SETTING: This study was conducted at a tertiary care rehabilitation center. PATIENTS: Thirty-three patients with chronic back and/or neck pain and 33 healthy volunteers matched for age, sex, and education participated in this study. OUTCOME MEASURES: A computerized version of a modified Stroop color-naming task, with unmasked and masked conditions, was used to assess strategic and automatic information processing of words related to sensory pain, affect pain, physical threat, social threat, and neutral themes. RESULTS: A repeated-measures ANOVA indicated that patients with chronic pain but not healthy volunteers had delayed color-naming latencies to both sensory and affect pain words in the unmasked condition. Color-naming latency differences were not evident for other word types in the unmasked condition or for any word types in the masked condition. Correlational and regression analyses indicated that the delayed color-naming latencies to pain words in the unmasked condition observed for the chronic pain patients were, in part, associated with high pain-specific cognitive anxiety and interference and lower levels of anxiety sensitivity. CONCLUSIONS: Individuals with chronic pain selectively process pain-related cues at the strategic level but not at the automatic level. Implications of the findings and future research directions are discussed.

New osmotically active hydrogel expander for enlargement of the contracted anophthalmic socket.

BACKGROUND: Clinical anophthalmia is characterized by the absence of an eyeball within the orbit and can result in overall growth retardation of the facial skeleton. The goal of treatment consists of fitting a serial prosthesis following rapid expansion of the contracted socket as soon as possible to achieve cosmetically acceptable eyelid and orbital symmetry. METHODS: Four children, aged 3-11 months, were treated by implantation of an anhydrous, highly hydrophilic tissue expander into the rudimentary conjunctival sac. With hydration of up to 98% in 72 h, the copolymer of methylmethacrylate and vinylpyrrolidone acts like an osmotically self-inducing socket expander. RESULTS: In the course of 2 months the previous contracted socket was enlarged, the horizontal lid length increased and the hydrated expander could be exchanged for a custom-made glass prosthesis. CONCLUSION: Preliminary results suggest that this new device can be used to avoid early plastic surgery of the eyelid. In addition, it also may enlarge the volume of the bony orbit.

[Clinical studies on the pathophysiology of odontogenic abscesses]. / Klinische Untersuchungen zur Pathophysiologie dentogen bedingter Abszesse.

In 26 patients with abscesses in the maxillofacial area, the electrolyte concentrations, pH and osmotic and hydrostatic pressures of the pus fluid were measured and calculated. The main cations identified were sodium (134 +/- 38 mmol/l) and potassium (37 +/- 16 mmol/l) and as anions chloride (183 +/- 46 mmol/l) and bicarbonate (10 +/- 4 mmol/l). The pH value of the pus liquid was 6.164 +/- 0.233. The calculated mean osmotic pressure of the pus liquid was 7910 +/- 1455 mm Hg, whereas the measured physical pressure inside the abscess was 49 +/- 13 mm Hg. Both pressure types show time-dependent pressure curves. With time, the real pressure inside the abscess cavity increases, whereas the osmotic pressure decreases. There was no relationship between the two pressure types and the different species of microorganisms responsible for the inflammation. The results of the study reveal that abscesses can be regarded as osmotically active systems, and the mechanism by which the abscess is formed might be as follows. After penetration of virulent microorganisms into the tissue space, the area of acute inflammation is walled off by the collection of inflammatory cells. Destruction of tissue by products of the polymorphonuclear leucozytes takes place and results in liquefactive necrosis and a hypertonic abscess cavity. The inwards-directed flow of tissue fluids into the cavity via the abscess membrane causes volume expansion and generates pressure, two facts that can explain the swelling dynamics and typical symptoms of abscesses in the maxillofacial area.

[Diagnostic and therapeutic concepts of canine fossa abscess. Evaluation of a multicenter study of 55 German-speaking departments of oromaxillofacial surgery]. / Diagnostische und therapeutische Konzepte des Fossa-canina-Abszesses. Auswertung einer multizentrischen Erhebung an 55 deutschsprachigen Abteilungen für Mund-, Kiefer- und Gesichtschirurgie.

A possible complication of fossa canina infections is reactive thrombosis of the vena angularis, which can lead to cavernous sinus phlebothrombosis. According to the literature there are different opinions about the treatment protocol of fossa canina abscesses. Therefore a multicentre study was undertaken in which 55 departments of oral surgery were interviewed using a standardized questionnaire about their procedures. The basis of diagnosis consists of clinical examination (100%), antibiogram (77.1%) and radiography (97.1%). A total of 28.6% use additional imaging procedures. Sonography is used by 20.0% and is found to be helpful in the diagnosis of vena angularis thrombosis. The painful palpation of the medial angle of the eye is of major diagnostic importance (100%) although anatomic variations of the vena angularis have to be considered. Extraoral incisions are not used in most cases (25.7% in exceptional cases) as well as ligations of the vena angularis in case of thrombosis (8.6% in exceptional cases). There is an agreement in the use of antibiotics (elective administration in 14.3%, obligatory administration in 85.7%); 77.1% don't use heparin to treat thrombosis of the vena angularis. In heparin therapy risks such as bleeding complications and thrombocytopenia have to be considered.

Complete response of a gastric primary after a short but toxic course of 'S-1' EORTC Early Clinical Studies Group.

We report the case of an unresected, metastatic gastric cancer, which was treated with a very short course of the oral 5-fluorouracil (5-FU) prodrug S-1. The patient had to discontinue chemotherapy during the first treatment cycle due to severe toxicity, but achieved a pathologically confirmed, long-term complete response of her primary tumour, a diffuse-type poorly differentiated adenocarcinoma.

Treatment of congenital anophthalmos with self-inflating polymer expanders: a new method.

Congenital anophthalmos is a rare malformation in which the optic vesicle fails to develop. This leads to a small bony orbit, a constricted mucosal socket, short eyelids, reduced palpebral fissure and malar hypoplasia. The treatment includes both aesthetic and functional aspects. Therefore, a two-step procedure is described using a new self-inflating hydrogel expander. A lens-shaped expander with a diameter of 8 mm expands the lids and the mucosal socket to allow insertion of an eye prosthesis. As a second step, orbital expansion is performed with a spherical device. The expanders absorb lacrimal fluid from the mucosal socket or tissue fluid and start swelling when implanted in the orbital tissue. The insertion of an expander into the orbit as well as into the conjunctival pocket including its fixation by a single suture took only a few minutes and was an easy procedure. The expansion of the small conjunctival sockets was successfully completed in all cases within a period of 2-4 weeks. The weight (= volume in ml) of devices increased from 0.15-1.5 g (lens-shaped expander; weight in grams = volume in ml) respectively, 0.3-3.5 g (spherical device). The expanders inserted in orbital tissue increased from 0.4-4.4 g. This is equivalent to a 10 to 11 fold increase in their water-free volumes. Orbital expansion with spherical devices in combination with the inserted eye prosthesis enlarges the lid and palpebral fissures also. In contrast to conventional silicon balloon expanders, the procedure using self-inflating hydrogel expanders is simple and highly efficient.