We used dynamic CT to identify two different time constants of lung aeration and their individual contribution to the total increase in cross-sectional lung area in healthy and experimentally damaged lungs. In five healthy pigs, inflation and deflation between 0 and 50 cm H2O was imposed during dynamic (250 ms/image) CT acquisition, and repeated after experimental lung injury by saline lavage. The fractional areas of density ranges, which represent aerated lung parenchyma, were determined planimetrically, and their time for expansion during the manoeuvre was fitted using a bi-exponential model. Thus, two compartments, their sizes, i.e. their relative contributions to lung area aerated by the manoeuvre, and their specific time constants (tau) were sought. Healthy lungs were characterized best by a one-compartmental behaviour with one tau only, both during inflation (median tau=0.5 s; range 0.4-0.6 s) and deflation (1.2 s; 1.1-1.3 s). In damaged lungs two compartments were found both during inspiration and expiration, with 86% (78-87%) of the recruitable lung area following a short tau of 0.5 s (0.5-0.6), and 14% (13-22%) following a longer tau of 9.1 s (8-16.8 s) during inflation. During expiration, damaged lungs had a short tau of 0.8 s (0.5-1.0 s) for 94% (84-100%) of deflated lung area, and a longer tau of 26.5 s (7.1-34.3 s) for 6% (0-16%). We conclude that dynamic CT indicates the relative size and temporal behaviour of functional compartments in normal and abnormal lungs. Our findings suggest that after lung damage, cyclic ventilation with inspiratory periods of <10 s duration will not achieve maximum recruitment for a chosen inspiratory pressure. In ARDS, the short expiratory tau predisposes to atelectasis formation if expiratory times are >1 s.

Augmentation of pedicle screws in general significantly increased the number of load cycles and failure load comparing to the nonaugmented control group. For the augmentation technique (cement first, in situ augmented, percutaneously application) no effect could be exhibited on the failure of the pedicle screws. By the cranio-caudal cyclic loading failure of the pedicle screws occurred by screw cut through the superior endplate and the characteristic "windshield-wiper effect", typically observed in clinical practice, could be reproduced.

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The purpose of this first patient study (phase II) was to evaluate the clinical usefulness of a new echo contrast agent at transcranial Doppler ultrasonography (US). Twenty patients were selected from a group of 242 patients undergoing conventional transcranial Doppler US who had low (n = 18) or absent (n = 2) Doppler signals from the middle cerebral artery (MCA). The extent and duration of Doppler signal increase was measured in 30 MCAs and in 14 basilar arteries following the intravenous injection of a transpulmonary galactose microparticle suspension (SH U 508 A) at three concentrations (200, 300, and 400 mg/mL). Doppler waveform analysis became possible in 93% (28 of 30) of the MCAs following injection. The maximal increase in average Doppler signal intensity (11 dB at 200 mg/mL, 15 dB at 300 mg/mL, and 17 dB at 400 mg/mL) and the increase in average duration of the signal enhancement (163 seconds at 200 mg/mL, 219 seconds at 300 mg/mL, and 240 seconds at 400 mg/mL) depended on contrast agent concentration. Doppler waveform analysis became possible in 79% (11 of 14) of the basilar arteries. The intravenous injection of this new echo contrast agent markedly increases Doppler signal intensity in patients with nondiagnostic results at conventional Doppler US.

The purpose of this study was to investigate condylar displacement related to the loss of posterior occlusal support. Each of 23 subjects received one occlusal adjusted splint that covered all teeth from the right to the left second mandibular molar. None of the subjects had a third molar and none of them had a missing tooth or showed tooth mobility. The splint was inserted and vertical and horizontal condylar position was measured by an ultrasonic motion analyser. The splint was then unilateraly shortened tooth-by-tooth up to the canine tooth and the measurement was repeated after each shortening. Cutting off the splint's second molar on one side lead to a slight ipsilateral cranial motion of the condyle if subjects clenched with maximum voluntary force. If the second and first molar were cut off, a noticeable cranial condylar movement of about 0.3 mm was observed even when teeth occluded with low force. These results suggest that loss of posterior occlusal support as it happens in routine oral rehabilitation leads to a noticeable cranial condyle movement during registration, even if the clenching force is low.

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Cerament (Bonesupport Holding, Lund, Sweden) is a bioresorbable synthetic bone substitute consisting of calcium sulfate and hydroxyapatite which is successfully used as a bone graft in bone defects or in delayed and non-unions after fractures. Besides, calcium sulfate/ hydroxyapatite (CAS/HA) could have, attributed to its composition and osteoinductive properties, have great importance in the treatment of bone infections with critical size defects (CSD). Aim of the study was to evaluate the effects of antibiotic infused CAS/HA on inflammation and bone healing in an implant-associated osteitis mice model. In a standardized murine model, the left femur of 72 BALB/c mice were osteotomized, generating a CSD (2,5 mm) with stabilization through a 6-hole titanium locking plate. Osteitis has been induced through inoculation of Staphylococcus aureus (SA) into the fracture gap. To analyze the effect of CAS/HA, following groups were generated with either CAS/HA, CAS/HA with gentamycin (CAS/ HA-G) or CAS/HA with vancomycin (CAS/HA-V) insets placed into the osteotomy. Debridément and lavages were progressed on day 7 and 42 to determine the local bacterial growth and the immune reaction. Fracture healing was quantified on day 7 and 42 by x-ray and bone healing markers from blood samples. Progression of infection was assessed by estimation of colony-forming units (CFU) and immune response was analyzed by determination of Interleukin (IL)– 6 and polymorphonuclear neutrophils (PMN) in lavage samples. Osteitis induced higher IL-6 and PMN-levels in the lavage samples on day 7. Both parameters showed a reduction in all groups on day 42. CAS/HA-V revealed a significant reduction of CFU and PMNs in lavage samples on day 42. A positive effect on bone healing could only be shown in non-infected mice. Whereas, application of mere CAS/HA in infected mice did show tendencies of bone destruction and lysis, independent of impregnation with antibiotics or not. Thus, application of CAS/HA in acute implant-associated infections is not recommended. In non-infectious environments or after infect-convalescence CAS/HA could albeit serve as a suggestive tool in trauma and orthopedic surgery.

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