Light transmittance and polymerization kinetics of amorphous calcium phosphate composites

Clinical Oral Investigations - This study investigated light transmittance and polymerization kinetics of experimental remineralizing composite materials based on amorphous calcium phosphate (ACP),...     

The Waist Width of Skis Influences the Kinematics of the Knee Joint in Alpine Skiing

Recently alpine skis with a wider waist width, which medially shifts the contact between the ski edge and the snow while turning, have appeared on the market. The aim of this study was to determine the knee joint kinematics during turning while using skis of different waist widths (65mm, 88mm, 110mm). Six highly skilled skiers performed ten turns on a predefined course (similar to a giant slalom course). The relation of femur and tibia in the sagital, frontal and coronal planes was captured by using an inertial motion capture suit, and Global Navigation Satellite System was used to determine the skiers’ trajectories. With respect of the outer ski the knee joint flexion, internal rotation and abduction significantly decreased with the increase of the ski waist width for the greatest part of the ski turn. The greatest abduction with the narrow ski and the greatest external rotation (lowest internal rotation) with the wide ski are probably the reflection of two different strategies of coping the biomechanical requirements in the ski turn. These changes in knee kinematics were most probably due to an active adaptation of the skier to the changed biomechanical conditions using wider skis. The results indicated that using skis with large waist widths on hard, frozen surfaces could bring the knee joint unfavorably closer to the end of the range of motion in transversal and frontal planes as well as potentially increasing the risk of degenerative knee injuries.

Key points

• The change in the skis’ waist width caused a change in the knee joint movement strategies, which had a tendency to adapt the skier to different biomechanical conditions.
• The use of wider skis or, in particular, skis with a large waist width, on a hard or frozen surface, could unfavourably bring the knee joint closer to the end of range of motion in transversal and frontal planes as well as may potentially increase the risk of degenerative knee injuries.
• The overall results of the abduction and internal rotation in respect to turn radii and ground reaction forces indicated that the knee joint movements are likely one of the key points in alpine skiing techniques. However, the skiing equipment used can still significantly influence the movement strategy.

Key words: Abduction, inertial sensor, rotation, ski turn, three-dimensional joint movements     

A case of interstitial pneumonitis in a patient with ulcerative colitis treated with azathioprine

The early hypersensitivity reaction and late bone marrow depression are well-known side-effects of azathioprine, whereas interstitial pneumonia is a rare complication. A 40-year old male patient had been treated with azathioprine in consequence of extensive ulcerative colitis for 10 years. He then complained of 7 d of fever, cough and catarrhal signs, without symptoms of active colitis. Opportunistic infections were ruled out. The chest X-ray, CT and lung biopsy demonstrated the presence of interstitial inflammation. Azathioprine therapy was discontinued as a potential source of the pulmonary infiltrate. In response to steroid therapy, and intensive care, the pulmonary infiltrate gradually decreased within 4 wk. Three months later, his ulcerative colitis relapsed, and ileo-anal pouch surgery was performed. In cases of atypical pneumonia, without a proven infection, azathioprine-associated interstitial pneumonitis may be present, which heals after withdrawal of the drug.     

The uncertainty in burn prediction as a result of variable skin parameters: An experimental evaluation of burn-protective outfits

The reliable prediction of burns, resulting from exposure to elevated levels of heat, received early interest in physiology and later on in various branches of applied research and engineering. In this paper we address the problem of estimating the extent of skin burns in the context of a quantitative assessment of protective garments from the statistical point of view. We rely on the experimental platform built around the thermal mannequin equipped with an array of thermal sensors. The dressed mannequin is first exposed to the flash fire, in order to determine the incident heat flux on the mannequin’s surface. This information is then used in a heat-transfer model of the skin, the result of which is an estimate of the degree of injury that would occur to a human exposed to the same flame conditions. The methods used so far, employed a deterministic skin model defined with the nominal thermal and geometrical parameters. However, skin properties differ from human to human and from one location on the body to another; this results in different configurations of the areas affected by injuries. In this paper we apply a Monte-Carlo approach to estimate the dispersion of the burns over a broad population of humans. The results obtained from experimental data records indicate that the variations in the dermis are the most decisive for increased dispersions at the estimated second- and third-degree burn areas.     

Clinical validation of fully 3-D versus 2.5-D RAMLA reconstruction on the Philips-ADAC CPET PET scanner

INTRODUCTION: Fully three-dimensional (3-D) reconstruction algorithms have the potential to better utilize PET data acquired in true 3-D acquisition modes, as compared to 2-D approaches involving data reduction through rebinning procedures followed by a 2-D or 2.5-D reconstruction. Our previous studies, involving simulated and real phantom data from PET scanners working purely in 3-D acquisition mode, showed that the fully 3-D reconstruction approaches bring appreciable improvement on physical measures and visual image quality as well. Reconstruction procedures utilized in those studies were based upon the row action maximum likelihood algorithm (RAMLA) implemented on our clinical scanners. The purpose of this study was to investigate if the fully 3-D RAMLA reconstruction software brings an appreciable improvement in clinical image quality and reader confidence. MATERIALS AND METHODS: Ninety patient scans acquired on the Philips CPET scanner at our institution were reconstructed using 2.5-D RAMLA and 3-D RAMLA with differing reconstruction parameters. These scans were blindly presented to four experienced PET scan readers who graded various aspects of image quality. RESULTS: Our study concluded that 3-D RAMLA on the CPET scanner reduces artifacts and image noise and improves clinical confidence in interpreting PET images. CONCLUSION: This study led to the routine use of 3-D RAMLA reconstruction on the CPET scanner at our institution.     

Pharmacokinetics of radiolabelled quinlukast in rats

Pharmacokinetics together with in vivo metabolism and elimination of quinlukast, a potential anti-asthmatic and anti-inflammatory drug, were designed in rats. For this purpose, bile duct cannulated rats and an in situ perfused rat liver preparation were employed. 3H-radiolabelled compound was administered i.v. or loaded to the perfusion medium, respectively. Quinlukast represented the main form of radioactivity determined in plasma; in comparison with the parent drug metabolites were present in lower levels in the systemic circulation. The pharmacokinetic parameters related to the whole animal were calculated from quinlukast rat plasma concentration-time course. The distribution of quinlukast in the body was relatively fast (distribution half-life was approx. 6 min), the elimination half-life exceeded 2h. Binding of quinlukast to rat plasma proteins was very high (approx. 99.7%) and this binding influenced distribution volumes of quinlukast. Both the volume of the central compartment and the volume at a steady state were approx. 115 and 430 ml, respectively. The experiments showed that the biliary clearance was the major route of elimination of this compound from the systemic circulation of rats. In agreement with the determined elimination half-life approx. 42% of the radioactivity was found in the bile, with <0.5% appearing in the urine. The majority of the eliminated radioactivity in the bile was in the form of polar metabolites; only a small part of the parent compound was determined. Two hours after intravenous administration, polar metabolites - but no parent drug - were detected in the urine.     

No prognostic impact of survivin expression in glioblastoma

Survivin is a member of a novel protein family of inhibitors of apoptosis, and also plays a role as a potent regulator of mitosis. In semiquantitative Western blot analysis of glioblastomas, survivin expression was shown to be a prognostically significant factor. In the present study we investigated the immunohistochemical expression of survivin and its prognostic impact in a large glioblastoma series comprising 104 consecutive adult patients undergoing a first operation for glioblastoma. We analyzed survivin, Ki-67, and topoisomerase-II-alpha expression in paraffin-embedded tissue, and correlated patient age, Karnofsky performance score, vascular pattern and survivin-, Ki-67-, topoisomerase-II-alpha-, and apoptotic indices with patient outcome using univariate and multivariate survival analysis. Survivin was expressed in all glioblastoma samples, and was prominent in a fraction of nuclei of tumor cells and vascular cells. Further, survivin labeled spindle- and chromosomal material of mitotic figures. Faint cytoplasmic expression was also seen. The survivin index showed significant correlation with Ki-67 and Topo-II-alpha indices. On average, 58.85% of Ki-67 and 91.08% of survivin-expressing nuclei co-expressed Ki-67 and survivin. The survivin index did not correlate significantly with overall survival, whereas patient age, Karnofsky performance score, vascular pattern, and Ki-67 and topoisomerase-II-alpha indices were associated with patient outcome. In summary, in glioblastoma, survivin is expressed predominantly in proliferating tumor cell nuclei. In contrast to Ki-67 and topoisomerase-II-alpha, survivin expression does not influence patient outcome. So, in contrast to Ki-67, survivin does not seem to be useful as prognostic factor in the clinical setting.     

Sublethal concentrations of ciprofloxacin induce bacteriocin synthesis in Escherichia coli

Antibiotics that interfere with DNA replication, as well as cell wall synthesis, induce the SOS response. In this report, we show that ciprofloxacin induces synthesis of colicins, narrow-spectrum antibiotics frequently produced by Escherichia coli strains, in an SOS-dependent manner.