In vitro characterization of a synthetic calcium phosphate bone graft on periodontal ligament cell and osteoblast behavior and its combination with an enamel matrix derivative

Objectives

Recent studies suggest that a combination of enamel matrix derivative (EMD) with grafting material may improve periodontal wound healing/regeneration. Newly developed calcium phosphate (CaP) ceramics have been demonstrated a viable synthetic replacement option for bone grafting filler materials.

Aims

This study aims to test the ability for EMD to adsorb to the surface of CaP particles and to determine the effect of EMD on downstream cellular pathways such as adhesion, proliferation, and differentiation of primary human osteoblasts and periodontal ligament (PDL) cells.

Materials and methods

EMD was adsorbed onto CaP particles and analyzed for protein adsorption patterns via scanning electron microscopy and high-resolution immunocytochemistry with an anti-EMD antibody. Cell attachment and cell proliferation were quantified using CellTiter 96 One Solution Cell Assay (MTS). Cell differentiation was analyzed using real-time PCR for genes encoding Runx2, alkaline phosphatase, osteocalcin, and collagen1α1, and mineralization was assessed using alizarin red staining.

Results

Analysis of cell attachment revealed significantly higher number of cells attached to EMD-adsorbed CaP particles when compared to control and blood-adsorbed samples. EMD also significantly increased cell proliferation at 3 and 5 days post-seeding. Moreover, there were significantly higher mRNA levels of osteoblast differentiation markers including collagen1α1, alkaline phosphatase, and osteocalcin in osteoblasts and PDL cells cultured on EMD-adsorbed CaP particles at various time points.

Conclusion

The present study suggests that the addition of EMD to CaP grafting particles may influence periodontal regeneration by stimulating PDL cell and osteoblast attachment, proliferation, and differentiation. Future in vivo and clinical studies are required to confirm these findings.

Clinical relevance

The combination of EMD and CaP may represent an option for regenerative periodontal therapy in advanced intrabony defects.     

Learning curve of medical students in ultrasound-guided simulated nerve block

Background

Good hand-eye coordination is a prerequisite for safe ultrasound-guided peripheral nerve blocks. However, new skills have to be acquired when compared to the traditional nerve stimulation technique. We tested and mathematically described the learning curve of these skills in inexperienced ultrasound users employing a simple phantom of a peripheral nerve.

Methods

A simple phantom made from a piece of spaghetti to simulate a nerve, within a starch core and embedded in gelatine was used for ultrasound-guided simulation of a peripheral nerve block. Eighteen medical students who were novices to ultrasound were enrolled. Serial time to successful injection was measured. Quality of injection was rated by two independent observers.

Results

Time to successful injection improved from a median of 66.5 s (49.5–90) for the first trial to 37 s (23.5–53.5) for the 11th trial. A plateau of 30 s was reached for t _1/2 after 2.7 trials and 4 × t _1/2 after 7.8 trials when described as first-order exponential decay. Time to successful injection was significantly shortened after 5 trials. Quality of injection with numbers of trials followed a sigmoidal shape with 50 % of maximum quality after 3.6 trials and a plateau after 8.5 trials. Likewise, a significant improved quality of injection was reached after 5 trials.

Conclusion

Based on our mathematical analyses of the learning curve, inexperienced ultrasound users can improve their hand-eye coordination within 5 subsequent trials in a simple model of a peripheral nerve block.     

Clinical manifestations of autosomal recessive polycystic kidney disease (ARPKD): kidney-related and non-kidney-related phenotypes

Autosomal recessive polycystic kidney disease (ARPKD), although less frequent than the dominant form, is a common, inherited ciliopathy of childhood that is caused by mutations in the PKHD1-gene on chromosome 6. The characteristic dilatation of the renal collecting ducts starts in utero and can present at any stage from infancy to adulthood. Renal insufficiency may already begin in utero and may lead to early abortion or oligohydramnios and lung hypoplasia in the newborn. However, there are also affected children who have no evidence of renal dysfunction in utero and who are born with normal renal function. Up to 30 % of patients die in the perinatal period, and those surviving the neonatal period reach end stage renal disease (ESRD) in infancy, early childhood or adolescence. In contrast, some affected patients have been diagnosed as adults with renal function ranging from normal to moderate renal insufficiency to ESRD. The clinical spectrum of ARPKD is broader than previously recognized. While bilateral renal enlargement with microcystic dilatation is the predominant clinical feature, arterial hypertension, intrahepatic biliary dysgenesis remain important manifestations that affect approximately 45 % of infants. All patients with ARPKD develop clinical findings of congenital hepatic fibrosis (CHF); however, non-obstructive dilation of the intrahepatic bile ducts in the liver (Caroli’s disease) is seen at the histological level in only a subset of patients. Cholangitis and variceal bleeding, sequelae of portal hypertension, are life-threatening complications that may occur more often in advanced cases of liver disease. In this review we focus on common and uncommon kidney-related and non-kidney-related phenotypes. Clinical management of ARPKD patients should include consideration of potential problems related to these manifestations.     

Subnormothermic machine perfusion for preservation of porcine kidneys in a donation after circulatory death model

Machine perfusion for preservation led to compelling success for the outcome of renal transplantation. Further refinements of methods to decrease preservation injury remain an issue of high interest. This study investigates functional and morphological aspects of kidneys preserved by subnormothermic (20 °C) machine perfusion (SNTM) compared with oxygenated hypothermic machine perfusion (HMPox) and cold storage (CS) in a donation after circulatory death (DCD) model. After 30 min of warm ischaemia, porcine kidneys were randomly assigned to preservation for 7 h by CS, HMPox or SNTM. Afterwards, kidneys were reperfused for 2 h with autologous blood in vitro for assessment of function and integrity. Application of SNTM for preservation led to significantly higher blood flow and urine output compared with both other groups. SNTM led to a twofold increased creatinine clearance compared with HMPox and 10‐fold increased creatinine clearance compared with CS. Structural integrity was best preserved by SNTM. In conclusion, this is the first study on SNTM for kidneys from DCD donors. SNTM seems to be a promising preservation method with the potential to improve functional parameters of kidneys during reperfusion.     

Language lateralization in patients with temporal lobe epilepsy: a comparison of functional transcranial Doppler sonography and the Wada test

This study prospectively investigates whether noninvasive functional transcranial Doppler sonography (fTCD) is a useful tool to determine hemispheric language lateralization in the presurgical evaluation of patients with medically intractable temporal lobe epilepsy (TLE). fTCD results were compared with the Wada test as the gold standard. Wada test and fTCD were performed in 13 patients suffering from TLE. fTCD continuously measured blood flow velocities in both middle cerebral arteries, while the patient was performing a cued word generation task. During the Wada test, spontaneous speech, comprehension, reading, naming, and repetition were investigated. A laterality index (LI) was obtained by both procedures. Due to a lack of an acoustic temporal bone window, fTCD could not be performed in two patients (15%). In 9 of the remaining 11 patients hemispheric language dominance was found on the left side, in 1 patient on the right side, and 1 patient showed bihemispheric language representation. In all patients fTCD and the Wada test were in good agreement regarding hemispheric language lateralization, and the LI of both techniques were highly correlated (r = 0.776, P = 0.005). fTCD gives predictions of hemispheric language dominance consistent with the Wada test results even in children, patients with low IQ, and nonnative speakers. It is an alternative to the Wada test in determining language lateralization in patients with temporal lobe epilepsy.     

Gastrocnemius recession leads to medial shift of gait line,impairment of muscle strength and improved dorsal extension in forefoot overload syndrome

Background

Gastrocnemius recession (GR) has been introduced for treatment of forefoot overload syndrome (FOS). We questioned if GR leads to an altered forefoot load and weakness of plantarflexors in those patients.

Identification of intrinsic and reflexive contributions to trunk stabilization in patients with low back pain: a case–control study

European Spine Journal - The goal of this study was to assess differences in low back stabilization and underlying mechanisms between patients with low back pain (LBP) and healthy controls. It has...