Prognostic tools for hypertrophic scar formation based on fundamental differences in systemic immunity

Unpredictable hypertrophic scarring (HS) occurs after approximately 35% of all surgical procedures and causes significant physical and psychological complaints. Parallel to the need to understanding the mechanisms underlying HS formation, a prognostic tool is needed. The objective was to determine whether (systemic) immunological differences exist between patients who develop HS and those who develop normotrophic scars (NS) and to assess whether those differences can be used to identify patients prone to developing HS. A prospective cohort study with NS and HS groups in which (a) cytokine release by peripheral blood mononuclear cells (PBMC) and (b) the irritation threshold (IT) after an irritant (sodium lauryl sulphate) patch test was evaluated. Univariate regression analysis of PBMC cytokine secretion showed that low MCP‐1, IL‐8, IL‐18 and IL‐23 levels have a strong correlation with HS (P < .010‐0.004; AUC = 0.790‐0.883). Notably, combinations of two or three cytokines (TNF‐a, MCP‐1 and IL‐23; AUC: 0.942, Nagelkerke R²: 0.727) showed an improved AUC indicating a better correlation with HS than single cytokine analysis. These combination models produce good prognostic results over a broad probability range (sensitivity: 93.8%, specificity 86.7%, accuracy 90,25% between probability 0.3 and 0.7). Furthermore, the HS group had a lower IT than the NS group and an accuracy of 68%. In conclusion, very fundamental immunological differences exist between individuals who develop HS and those who do not, whereas the cytokine assay forms the basis of a predictive prognostic test for HS formation, the less invasive, easily performed irritant skin patch test is more accessible for daily practice.     

Posaconazole therapeutic drug monitoring in clinical practice and longitudinal analysis of the effect of routine laboratory measurements on posaconazole concentrations

Posaconazole is indicated for prophylaxis and treatment of invasive aspergillosis. Therapeutic drug monitoring (TDM) of posaconazole is used to optimise drug exposure. The aim of this study was to analyse and describe the TDM practices and exposure of posaconazole tablets. Patients who received posaconazole for treatment or prophylaxis of fungal infections were included in the study. The following therapeutic window was defined: if concentration was low (<0.7 mg/L for prophylaxis or < 1.5 mg/L for treatment) or high (>3.75 mg/L), the hospital pharmacist provided the physician with dosage advice, which implementation to patient care was analysed. A longitudinal analysis was performed to analyse if different confounding variables had an effect on posaconazole concentrations. Forty‐seven patients were enrolled resulting in 217 posaconazole trough concentrations. A median of 3 (IQR 1‐7) samples was measured per patient. The median concentration was 1.7 mg/L (IQR 0.8‐2.7) for prophylaxis and 1.76 mg/L (IQR 1.3‐2.3) for treatment. Overall, 78 posaconazole concentrations were out of the therapeutic window. For 45 (54%) of these concentrations, a dosage change was recommended. In the longitudinal analysis, the laboratory markers and patient baseline variables did not have an effect on posaconazole concentrations. Adequate posaconazole exposure was shown in 64% (affected 28 patients) of the measured concentrations. TDM practice of posaconazole can be improved by increasing the implementation rate of dose recommendation by a multidisciplinary antifungal stewardship team.     

One Week of Hospitalization Following Elective Hip Surgery Induces Substantial Muscle Atrophy in Older Patients

Objectives

Short successive periods of skeletal muscle disuse have been suggested to substantially contribute to the observed loss of skeletal muscle mass over the life span. Hospitalization of older individuals due to acute illness, injury, or major surgery generally results in a mean hospital stay of 5 to 7 days, during which the level of physical activity is strongly reduced. We hypothesized that hospitalization following elective total hip arthroplasty is accompanied by substantial leg muscle atrophy in older men and women.

Task-evoked reconfiguration of the fronto-parietal network is associated with cognitive performance in brain tumor patients

Brain Imaging and Behavior - In healthy participants, the strength of task-evoked network reconfigurations is associated with cognitive performance across several cognitive domains. It is, however,...     

The feasibility of quantitative MRI of extra‐ocular muscles in myasthenia gravis and Graves' orbitopathy

Although quantitative MRI can be instrumental in the diagnosis and assessment of disease progression in orbital diseases involving the extra‐ocular muscles (EOM), acquisition can be challenging as EOM are small and prone to eye‐motion artefacts. We explored the feasibility of assessing fat fractions (FF), muscle volumes and water T2 (T2_water) of EOM in healthy controls (HC), myasthenia gravis (MG) and Graves' orbitopathy (GO) patients. FF, EOM volumes and T2_water values were determined in 12 HC (aged 22‐65 years), 11 MG (aged 28‐71 years) and six GO (aged 28‐64 years) patients at 7 T using Dixon and multi‐echo spin‐echo sequences. The EOM were semi‐automatically 3D‐segmented by two independent observers. MANOVA and t‐tests were used to assess differences in FF, T2_water and volume of EOM between groups (P < .05). Bland–Altman limits of agreement (LoA) were used to assess the reproducibility of segmentations and Dixon scans. The scans were well tolerated by all subjects. The bias in FF between the repeated Dixon scans was ?0.7% (LoA: ±2.1%) for the different observers; the bias in FF was ?0.3% (LoA: ±2.8%) and 0.03 cm³ (LoA: ± 0.36 cm³) for volume. Mean FF of EOM in MG (14.1% ± 1.6%) was higher than in HC (10.4% ± 2.5%). Mean muscle volume was higher in both GO (1.2 ± 0.4 cm³) and MG (0.8 ± 0.2 cm³) compared with HC (0.6 ± 0.2 cm³). The average T2_water for all EOM was 24.6 ± 4.0 ms for HC, 24.0 ± 4.7 ms for MG patients and 27.4 ± 4.2 ms for the GO patient. Quantitative MRI at 7 T is feasible for measuring FF and muscle volumes of EOM in HC, MG and GO patients. The measured T2_water was on average comparable with skeletal muscle, although with higher variation between subjects. The increased FF in the EOM in MG patients suggests that EOM involvement in MG is accompanied by fat replacement. The unexpected EOM volume increase in MG may provide novel insights into underlying pathophysiological processes.     

A new method to evaluate the effects of shear on the skin

Currently, pressure ulcer preventive strategies focus mainly on pressure redistribution. Little attention is paid to reduce the harmful effects of shear‐force, because little is known about pathophysiological aspects of shear‐force. Even today, no method to measure the effects of shear‐force on the skin is available. Therefore, the aim of this study was to investigate the response to shear‐forces in terms of analyzing a noninvasive biomarker and reactive hyperemic parameter measured at the skin of healthy participants. A physical model was developed to produce a combination of pressure and shear or pressure alone on the skin. Ten healthy male participants were included and pressure (3.9 kPa) and a combined loading of pressure and shear (2.4 kPa + 14.5 N) was applied at the volar aspect of the forearms for 15 and 30 minutes. A Sebutape sample was used to collect IL‐1α and total protein (TP) noninvasively. The reactive hyperemic parameter was derived from a laser Doppler flowmeter. The increase in IL‐1α/TP‐ratio after a combined loading of pressure and shear for 30 minutes of 6.2 ± 2.5 was significantly higher compared with all other test conditions (p < 0.05). The increase in cutaneous blood cell flux was already significantly higher when a combined loading of pressure and shear was applied for 15 minutes compared with pressure alone. These results shows that the IL‐1α/TP‐ratio and cutaneous blood cell flux can be used as robust measures of the effect of shear‐force on skin in humans. Therefore, this model can be used to evaluate materials aimed at the reduction of shear.