Polyaspartic acid facilitates oxolation within iron(iii) oxide pre-nucleation clusters and drives the formation of organic-inorganic composites.

The interplay between polymers and inorganic minerals during the formation of solids is crucial for biomineralization and bio-inspired materials, and advanced material properties can be achieved with organic-inorganic composites. By studying the reaction mechanisms, basic questions on organic-inorganic interactions and their role during material formation can be answered, enabling more target-oriented strategies in future synthetic approaches. Here, we present a comprehensive study on the hydrolysis of iron(iii) in the presence of polyaspartic acid. For the basic investigation of the formation mechanism, a titration assay was used, complemented by microscopic techniques. The polymer is shown to promote precipitation in partly hydrolyzed reaction solutions at the very early stages of the reaction by facilitating iron(iii) hydrolysis. In unhydrolyzed solutions, no significant interactions between the polymer and the inorganic solutes can be observed. We demonstrate that the hydrolysis promotion by the polymer can be understood by facilitating oxolation in olation iron(iii) pre-nucleation clusters. We propose that the adsorption of olation pre-nucleation clusters on the polymer chains and the resulting loss in dynamics and increased proximity of the reactants is the key to this effect. The resulting composite material obtained from the hydrolysis in the presence of the polymer was investigated with additional analytical techniques, namely, scanning and transmission electron microscopies, light microscopy, atomic force microscopy, zeta potential measurements, dynamic light scattering, and thermogravimetric analyses. It consists of elastic, polydisperse nanospheres, ca. 50-200 nm in diameter, and aggregates thereof, exhibiting a high polymer and water content.

Anti-neutrophil cytoplasmic antibody associated vasculitis of the brain and oral cavity: a case report.

We report a patient with a novel presentation of anti-neutrophil cytoplasmic antibody positive (ANCA+) vasculitis of the brain and oral mucosa. ANCA+ vasculitis of the brain is usually associated with pachymeningitis and hypophysitis, and there are no cases reported with simultaneous brain and oral mucosal involvement. A 35-year-old African Zambian man presented with headache and bleeding swollen gingiva. He was myeloperoxidase (MPO) antibody positive with cytoplasmic staining. His MRI showed stable small callosal, periventricular and subcortical white matter non-enhancing lesions, without change over 15 months-compatible with vasculitis. His gingival biopsy was consistent with vasculitis. His headache and oral lesions responded to oral corticosteroids and intravenous immunoglobulin which have induced clinical remission. Our patient expands the clinical syndrome of ANCA+ MPO+ C-type vasculitis of the central nervous system with headaches complicating cerebral vasculitis and oral mucosal involvement.

Antibiotic prophylaxis in oral and maxillofacial surgery: a systematic review.

Surgical site infections are a complication of oral and maxillofacial procedures, with the potential for significant morbidity and mortality. Use of preoperative, perioperative, and postoperative antibiotic prophylaxis to reduce the incidence of surgical site infections must be balanced with considerations of a patients' risk of antibiotic-related adverse events. This review aimed to provide evidence-based recommendations for antibiotic prophylaxis. Searches were conducted using MEDLINE, the Cochrane Library, EMBASE, and PUBMED for maxillofacial procedures including: treatment of dental abscesses, extractions, implants, trauma, temporomandibular joints, orthognathics, malignant and benign tumour removal, and bone grafting, limited to articles published since 2000. A total of 98 out of 280 retrieved papers were included in the final analysis. Systematic reviews were assessed using AMSTAR criteria. Randomised controlled trials were assessed for bias using Cochrane Collaborative tools. The overall quality of evidence was assessed using GRADE. Prophylactic antibiotic use is recommended in surgical extractions of third molars, comminuted mandibular fractures, temporomandibular joint replacements, clean-contaminated tumour removal, and complex implants. Prophylactic antibiotic use is not routinely recommended in fractures of the upper or midface facial thirds. Further research is required to provide recommendations in orthognathic, cleft lip, palate, temporomandibular joint surgery, and maxillofacial surgical procedures in medically-compromised patients.

Metastatic epithelioid haemangioendothelioma masquerading as periodontal pathosis: a case report.

We present a non-healing lesion on the gingivae attached to the mandible that mimicked periodontal disease, and was refractory to local debridement and oral hygiene measures. Biopsy examination showed a metastatic epithelioid haemangioendothelioma. This rare vascular tumour is considered to be malignant and management is controversial, owing to the paucity of published data. Treatment was provided in a multi-disciplinary setting as a result of established pulmonary and musculoskeletal metastases. The patient opted for conservative management and close surveillance of the lesion, which continues to remain stable at the time of writing, nearly two years after the initial assessment.

Current and evolving trends in the management of facial fractures.

The oral and maxillofacial region has a complex regional anatomy including hard and soft tissues. Trauma in this region may affect the airway, cause potentially life threatening bleeding and head injuries. The senses of olfaction, sight and hearing can also be disrupted as well as a profound psychological impact following disfigurement. This oral and maxillofacial trauma update provides information on demographics, incidence, pathophysiology, diagnosis, fracture patterns and management of facial trauma. It also discusses the role of new advancements in the management of facial trauma.

Retrospective comparison of the number of screws used for fixation of skeletal anchorage plates in orthodontics, and their failure rates.

The aim of this study was to compare the failure rate of fixation of skeletal orthodontic anchorage plates (SAP) with two screws with that of three screws, and to find out if there is a relation between the number of screws used to fix the plates and the failure rate. We reviewed clinical records of 65 patients from five hospitals with 176 SAP, and took into account other factors that may have affected the failure. The overall failure rate was 15/176 (8.5%), and for with two-screw fixation it was 9/86 compared with 6/90 for those with three-screw fixation. Age, sex, and coexisting medical conditions did not affect the failure rate. There was a higher failure rate for those placed in the mandible (11/105) than for those placed in the maxilla (4/71). SAP provide a stable source of skeletal anchorage for orthodontic treatment. Our results show that those fixed with two screws may be marginally more likely to fail than those fixed with three, but further studies are needed to investigate the association between failure and the number of screws used.

Clinical guideline for the management of odontogenic infections in the tertiary setting.

BACKGROUND: Odontogenic infections are a common presentation to emergency departments of Australian hospitals. Due to the limited training in diagnosis and treatment of dental conditions, these patients can present a challenge for the medical practitioner. The objective of this study was to provide an evidence-based approach to the management of odontogenic infections in adults presenting to Royal Perth Hospital. METHODS: A literature search was conducted to identify evidence-based guidelines for the management of odontogenic infections in the tertiary hospital setting. Keywords 'dental', 'infections' and 'management' were used to search PubMed, DynaMed and Embase databases. RESULTS: Recommendations were drawn from existing literature including coroner reports with respect to clinical assessment, investigations, medical and surgical management, and postoperative care. A flow chart, incorporating these recommendations, was created to allow for appropriate disposition of patients presenting with odontogenic infections to Royal Perth Hospital. CONCLUSIONS: A clinical guideline is needed to appropriately manage patients presenting with odontogenic infections. We recommend the guideline be submitted to intradepartmental committees for assessment.

Ultraflexible vesicles, Transfersomes, have an extremely low pore penetration resistance and transport therapeutic amounts of insulin across the intact mammalian skin.

New vehicles for the non-invasive delivery of agents are introduced. These carriers can transport pharmacological agents, including large polypeptides, through the permeability barriers, such as the intact skin. This capability depends on the self-regulating carrier deformability which exceeds that of the related but not optimized lipid aggregates by several orders of magnitude. Conventional lipid suspensions, such as standard liposomes or mixed lipid micelles, do not mediate a systemic biological effect upon epicutaneous applications. In contrast to this, the properly devised adaptable carriers, when administered on the intact skin, transport therapeutic amounts of biogenic molecules into the body. This process can be nearly as efficient as an injection needle, as seen from the results of experiments in mice and humans with the insulin-carrying vesicles. The carrier-mediated transcutaneous insulin delivery is unlikely to involve shunts, lesions or other types of skin damage. Rather than this, insulin is inferred to be transported into the body between the intact skin cells with a bio-efficiency of at least 50% of the s.c. dose action.

Localization of a high molecular weight form of DNA topoisomerase I in amphibian oocytes.

Xenopus oocytes express a 165 kDa variant of DNA topoisomerase I (topo I) as opposed to the canonical 110 kDa form of somatic cells (Richard and Bogenhagen, Dev. Biol. 146: 4-11, 1991). By immunofluorescence microscopy using variant-specific antibodies we show that this high molecular weight form is associated with lampbrush chromosome loops and the inner regions of the amplified nucleoli. Inhibition of topo I-activity by either Camptothecin-treatment or microinjection of neutralizing antibodies resulted in loop retraction and the condensation of chromosomes and amplified nucleoli. These data indicate that the oocyte-specific 165 kDa form of topo I is involved in transcriptional processes mediated by RNA polymerase I and II and is therefore functionally equivalent to the somatic cell 110 kDa counterpart.

Changes in cadaveric cancellous vertebral bone strength in relation to time. A biomechanical investigation.

STUDY DESIGN: A biomechanical study was conducted during a 3.5-day period to test for changes occurring in pullout strengths of cancellous screws inserted into human cadaveric vertebral bodies. OBJECTIVES: To quantify, within the testing time of 3.5 days, the possible changes to the mechanical properties of cadaveric vertebral bodies, resulting from structural degradation caused by postmortem, time-dependent, autolytic processes during mechanical testing of implant-bone biomechanics. SUMMARY OF BACKGROUND DATA: Biomechanical testing of whole spinal implants and analysis of the screw-bone interface of spinal implants is an area of clinical interest that frequently requires the use of cadaveric spine specimens. Changes in vertebral bone properties during the testing period may invalidate experimental results, but no data are available on degradation of bone during the testing period. METHODS: Anterior oblique cancellous screws were inserted into human vertebral bodies from which the ventral cortex had been removed. The pullout strength was measured at 0, 24, 60, and 84 hours after insertion. The tests were performed on 48 human vertebral bodies, which were stored by freezing to -23 C, thawed for testing, and kept at room temperature during the testing time for as long as 84 hours. RESULTS: The axial pullout strength showed no statistically significant change during 84 hours (P = 0.15). There were no significant differences attributable to vertebral level from T4 to L4, probably because the ventral cortices had been removed (P = 0.7). CONCLUSIONS: During 3.5 days, there were no changes in pullout strength of vertebral cancellous bone. In biomechanical studies during a maximum period of 3 days with a small number of cadaveric spines (e.g., four spine specimen) the time-dependent changes in pullout strength play a less significant role than do the interspine differences. Interspine differences should be regarded as an important factor to be considered in the design of biomechanical tests.

[X-ray transparency of common orthopedic casts]. / Die Röntgenstrahlentransparenz gebräuchlicher stabiler Stützverbände.

X-ray permeability is one of the important criterions which qualify a material as orthopedic cast. By using a phantom (amputated human lower leg) standardized conditions were created to compare the five customary casts: Cellamin, Lightcase II, Hexcelite, Neofrakt and Baycast. For judging the perceptibility of osseous structures, especially the details of the fracture, the lower and the upper number of clinically used layers were considered. The blank tested valuation showed the well-known advantages of the plastic materials in comparison with plaster of Paris. Within the group of the plastic materials distinct differences were also found.

[Effect of surgical laser on collagen-rich tissue]. / Untersuchungen zur Wirkung chirurgischer Laser auf kollagenreiche Gewebe.

The goal of this ex-vivo study was a controlled macroscopical and microscopical comparison of the immediate effects of surgical lasers on dense collagenous tissues. The investigation of the exact denaturizing effects following tissue interaction between lasers and collagenous fibers are of importance for a better understanding of the observed and described healing process. Partial tenotomies were performed ex vivo on sixty tendons of the flexor digitorum profundus muscle of New Zealand White Rabbits using four surgical lasers (Holmium:YAG-, Erbium:YAG-, Neodym:YAG-, and CO2-Laser). The tendons were evaluated macroscopically, histologically and observations were made on the surgical handling of the lasers during the procedure. The choice of lasers allowed the comparison of a wide spectrum of wavelengths (gamma = 1.0 to 10.6 microns). In addition, beam delivery modalities were compared to each other (focus vs. contact). The pulse (frequency and power) was varied within each laser. Other parameters including focus size, absorption, dispersion, and thermal tissue conductivity were maintained constant in this test arrangement in order to allow a later comparison between the observed areas of denaturated collagen. The macroscopical and histological results showed great differences in the effects of the four lasers. Even within each single laser group, the results varied greatly with the choice of variable parameters. Holmium:YAG- and CO2-Laser can produce similar areas of collagen denaturation. When comparing specimens with similar areas of collagen denaturation induced by different laser types, different amounts of charring were observed. Erbium:YAG-Laser tenotomies showed generally inhomogeneous denaturation areas, while tenotomies with Neodym: YAG-Laser used in continuous mode resulted in significant charring and tissue retraction in the area of interaction. These observations help in defining the combination of parameters with which Holmium:YAG-, Erbium:YAG-, and CO2-Lasers can be used for transsection of dense collagenous tissues. In addition, these histological results as well as already published observations on healing patterns following laser surgery allow for the formulation of a hypothesis on the effects of laser in the wound healing process.

[The cementless artificial hip cup--implant components with reliable long-term stability?]. / Die zementlose Hüftgelenkspfanne-Die Implantatkomponente mit gesicherter Langzeitstabilität?

A hip joint simulator was developed to analyse the mechanism of loosening of cementless artificial hip cups. The machine induces vibrating motions and asymmetrical tilt shock loadings of the artificial cup. On measuring the primary stability of threaded cups, the simulation tests performed on pelvis substitute models, and animal and human acetabula failed to show any loosening of threaded cups fixed in place with a screw-in torque of more than 10 Nm. Instable cups became loose all the sooner, the lower the preload between the cup and femoral head. This demonstrates the importance of both the screw-in torque of the cup and the training status of the periarticular muscles.

The wireless monitoring of vital parameters: a design study.

This project shows the way vital parameters can be transmitted and visualized with no connecting cables necessary to the PDA. This was realized using a sensor developed with an integrated Bluetooth interface and a PDA, also equipped with Bluetooth. This radio connection can span up to 10 m, and parameters, such as pulse frequency, oxygen saturation in blood, ECG measurements and plethysmograms, can be transmitted. Using the software introduced in this work, the transmitted measurements can be displayed numerically or graphically on the PDA. The software simultaneously checks for any limits and sends a warning message if these limits are exceeded. All received data are additionally documented.

[Neurophysiological and biomechanical analysis of a gymnastics accident with high transverse paralysis. An example of a sports medicine research study in the area of prevention of sports accidents]. / Neurophysiologische und biomechanische Analyse eines Kunstturnunfalles mit hoher Querschnittslähmung. Beispiel einer sportmedizinischen Forschungsstudie im Bereich der Prävention von Sportunfällen.

The development of preventive provisions is an important topic of sport accident research. We demonstrate the stepwise procedure of judging a provision taking the analysis of a gymnastic exercise. This includes determination of the inner and outer reasons of accidents, the biomechanical conditions of the exercise and leads to mathematical and experimental simulation of the dangerous movement. The specific exercise we studied was the efficiency of a coach in protecting position for the handstand somersault with 1 1/2 breakneck leap. The reaction ability of the coach during the exercise and his force capacity to prevent an accident is explored by a newly developed reaction time analyzer and by a catapult apparatus throwing a dummy. Our results show the inadequacy of the prevention provision of a coach in protecting position for the special gymnastic exercise.

[Extreme loading as cause of aseptic loosening of the total hip endoprosthesis socket and the resultant therapeutic consequences]. / Extrembelastungen als Ursachen für aseptische Lockerungen von Hüfttotalendoprothesen--Pfannen und daraus resultierende therapeutische Konsequenzen.

An analysis of the extent of damage in explanted endoprostheses of the hip showed massive destructions of the implanted components, such as fractures of the socket etc. For this reason, the authors designed a mathematical model of the extremity for which a prosthesis is designed; this model can simulate, inter alia, extreme loads of the joint occurring, for example, when a person falls. Self-experiments were helpful in determining the load exercised on the hip joint under such extreme conditions and in defining the effects on implanted joint material and the interface between bone and bone cement. Besides the influence of the body weight and the height of a fall, we also investigated dependence on attenuation promoted by different kinds of shoeware. These extreme loads in everyday life, which result in an excess stress of the materials and the interface, provide a good explanation for the aseptic loosening of the primarily well-fixed socket. From the therapeutic point of view these results suggest that such extreme burdening should be avoided during the time in which repair processes take place to gradually reduce the heat necroses in the osseous bed of the acetabulum which are due to the cement, by exercising a partial load only for three months after the operation rather than applying the full load too early. Attenuation of shock achieved by the use of various shoe materials was studied in self-experiments in which the researcher allowed himself to fall from different heights on to an outstretched leg while wearing different types of shoes.(ABSTRACT TRUNCATED AT 250 WORDS)

Differences in integrity of white matter and changes with training in spelling impaired children: a diffusion tensor imaging study.

While the functional correlates of spelling impairment have been rarely investigated, to our knowledge no study exists regarding the structural characteristics of spelling impairment and potential changes with interventions. Using diffusion tensor imaging at 3.0 T, we here therefore sought to investigate (a) differences between children with poor spelling abilities (training group and waiting group) and controls, and (b) the effects of a morpheme-based spelling intervention in children with poor spelling abilities on DTI parameters. A baseline comparison of white matter indices revealed significant differences between controls and spelling-impaired children, mainly located in the right hemisphere (superior corona radiata (SCR), posterior limb of internal capsule, superior longitudinal fasciculus). After 5 weeks of training, spelling ability improved in the training group, along with increases in fractional anisotropy and decreases of radial diffusivity in the right hemisphere compared to controls. In addition, significantly higher decreases of mean diffusivity in the right SCR for the spelling-impaired training group compared to the waiting group were observed. Our results suggest that spelling impairment is associated with differences in white-matter integrity in the right hemisphere. We also provide first indications that white matter changes occur during successful training, but this needs to be more specifically addressed in future research.