Acetyl-CoA synthetase activity is enzymatically regulated by lysine acetylation using acetyl-CoA or acetyl-phosphate as donor molecule.

The AMP-forming acetyl-CoA synthetase is regulated by lysine acetylation both in bacteria and eukaryotes. However, the underlying mechanism is poorly understood. The Bacillus subtilis acetyltransferase AcuA and the AMP-forming acetyl-CoA synthetase AcsA form an AcuA•AcsA complex, dissociating upon lysine acetylation of AcsA by AcuA. Crystal structures of AcsA from Chloroflexota bacterium in the apo form and in complex with acetyl-adenosine-5'-monophosphate (acetyl-AMP) support the flexible C-terminal domain adopting different conformations. AlphaFold2 predictions suggest binding of AcuA stabilizes AcsA in an undescribed conformation. We show the AcuA•AcsA complex dissociates upon acetyl-coenzyme A (acetyl-CoA) dependent acetylation of AcsA by AcuA. We discover an intrinsic phosphotransacetylase activity enabling AcuA•AcsA generating acetyl-CoA from acetyl-phosphate (AcP) and coenzyme A (CoA) used by AcuA to acetylate and inactivate AcsA. Here, we provide mechanistic insights into the regulation of AMP-forming acetyl-CoA synthetases by lysine acetylation and discover an intrinsic phosphotransacetylase allowing modulation of its activity based on AcP and CoA levels.

Transcutaneous electrical nerve inhibition using medium frequency alternating current.

Transcutaneous medium-frequency alternating electrical current is defined as an alternating current between 1 and 10 kHz and is capable of producing an instant, reversible block. This study aims to evaluate the efficacy of sensory perception and force production of the index and middle finger after transcutaneous medium-frequency alternating electrical current stimulation of the distal median nerve. A single-center prospective interventional cohort study was conducted in adult healthy volunteers at the Jessa Hospital, Hasselt, Belgium. Two different electrodes (PALS & 3M) were placed on the distal median nerve, which was located using a Sonosite X-Porte Ultrasound transducer, with the first electrode being placed on the skin at the level of the transverse carpal ligament and the second electrode 7 cm proximally to the first electrode. The tactile sensation was evaluated with Semmes-Weinstein monofilament test and sensation of pressure/pain was evaluated with an algometer. Peak force production was assessed with an electronic dynamometer. All measurements were performed at baseline and tMFAEC stimulation frequencies of 2 and 10 kHz in a randomized manner. Statistical analysis was performed with a one-way ANOVA with repeated measures test or a Friedman rank sum test, followed by the Wilcoxon signed rank test adjusted with Bonferroni correction. A p-value < 0.05 was considered statistically significant. From 9 to 13th of April 2021, 25 healthy volunteers were included in the Jessa Hospital, Hasselt, Belgium. A statistically significant reduction in tactile sensation during 2 kHz and 10 kHz stimulation compared to baseline was observed (2.89 ± 0.22 (PALS2); 3.35 ± 0.25 (3M2) and 2.14 ± 0.12 (PALS10); 2.38 ± 0.12 (3M10) versus - 1.75 ± 0.09 (baseline), p < 0.0001). 3M electrodes showed a tendency towards the elevation of pressure pain threshold compared to baseline. No significant difference in mean peak forces of the index and middle fingers after transcutaneous medium-frequency alternating electrical current stimulation with 2 and 10 kHz was found. This study demonstrates that transcutaneous medium-frequency alternating electrical current stimulation on the distal median nerve inhibits tactile sensory nerve activity in the index and middle finger when stimulation of 2 kHz and, to a lesser extent, 10 kHz was applied. A reduction of motor nerve activity was not observed but force production measurements may be prone to error.Trial registration: clinicaltrials.gov on 01/04/2021. NCT-Number: NCT04827173.

A novel assay to assess the effect of pharmaceutical compounds on the differentiation of podocytes.

BACKGROUND AND PURPOSE: Therapeutic options for treating glomerulopathies, the main cause of chronic kidney disease, are limited. Podocyte dedifferentiation is a major event in the pathogenesis of glomerulopathies. The goal of the present study was, therefore, to develop an assay to monitor podocyte differentiation suitable for compound screening. EXPERIMENTAL APPROACH: We isolated and cultured glomeruli from transgenic mice, expressing cyan fluorescent protein (CFP) under the control of the promoter of nephrin, a marker of podocyte differentiation. Mean CFP fluorescence intensity per glomerulus (MFG) was determined by summation of all glomerular voxels from confocal z-stacks in the absence and presence of pharmaceutical compounds. KEY RESULTS: In untreated cultured glomeruli, MFG remained fairly stable during the first 5 days, when foot processes were already effaced, and the level of many podocyte-specific proteins was only mildly affected, as revealed by proteomics. Between day 6 and 9, MFG decreased to almost zero. The decrease in MFG was paralleled by a decrease in CFP and nephrin expression, as determined by RT-PCR, western blots and proteomics. Puromycin aminonucleoside (PAN), which damages podocytes, concentration-dependently induced a complete loss of MFG. Dexamethasone (25 µM) and pioglitazone (10 µM) markedly attenuated the effect of 0.6 µg·mL-1 PAN on MFG. CONCLUSION AND IMPLICATIONS: In summary, we established a novel assay to assess the effect of pharmaceutical compounds on the differentiation of podocytes in situ. Our assay is suitable for compound screening to identify drugs for the treatment of glomerulopathies.

Nonunion of a Pediatric Distal Radial Metaphyseal Fracture Following Open Reduction and Internal Fixation : A Case Report and Review of the Literature.

A boy, age 9, presented with deformation and pain of the left distal forearm, 1 year after a plate osteosynthesis for a distal radial metaphyseal fracture. This case showed a pediatric nonunion of a distal radial metaphyseal fracture which caused strong deformation of the left distal forearm. This is an extremely rare complication in children following an open reduction and internal fixation for a displaced distal forearm fracture. Key points of pediatric fracture healing are discussed and a review of the literature is given.

Late spontaneous haemarthrosis: an unusual complication following an unicompartmental knee arthroplasty.

A man, aged 55, presented with a spontaneous haemarthrosis of his right knee, 1 year after an unicompartmental knee replacement. This case showed an atraumatic rupture of the metal marker wire of an all-polyethylene inlay tibial implant which caused a destruction of the polyethylene surface and a disseminated synovitis of the right knee. This is a rare but destructive complication following an unicompartmental knee arthroplasty.

Percutaneous epiphysiodesis for leg length discrepancy.

This study presents a retrospective evaluation of 57 patients who underwent a percutaneous epiphysiodesis for leg length discrepancy. Of these patients, 68.5% presented with a good result with a final leg length discrepancy of less than 1.5 cm, 14% with a fair result with a discrepancy of between 1.5 and 2 cm, and 17.5% showed a poor result with a leg length discrepancy of more than 2 cm. The percutaneous epiphysiodesis was found to be a safe and reliable technique. There were very few technical errors. The causes of failure were analyzed and compared with a previous study from the same department. Error in timing remains the main problem.

Avascular necrosis of the talus in children with haemophilia.

Patients who have haemophilia often present with joint problems. Haemarthrosis can occur spontaneously or after minor trauma. Later, degenerative changes can cause pain and loss of motion. Avascular necrosis of the talus has a high incidence after serious trauma. Furthermore, avascular necrosis of the talus has been associated with multiple systemic conditions. The association of haemophilia and avascular necrosis of the femoral head has been described. This study reports three cases (four ankles) where we suspect an avascular necrosis of the talus in children with haemophilia. To the authors' knowledge, the possible association of haemophilia and avascular necrosis of the talus has not yet been described in children.

Pre-axial polydactyly: outcome of the surgical treatment.

From 1988 to 1999 we operated on 22 patients for pre-axial polydactyly. We retrospectively reviewed all files and we clinically reviewed 16 patients. We report on the epidemiology, the surgical technique, the outcome and the complications. All patients were operated on by the same hand surgeon (L.D.S.) and reviewed by an independent observer (S.K.). Aesthetic and functional outcome is reported. In general the surgical treatment for pre-axial duplications gives excellent functional and good aesthetic results. According to the Egawa score, 13 patients obtained an excellent, one a fair and two a poor result. The overall satisfaction rate is very high for both patient and parents and the complication rate was low. The functional outcome seems to be related to the stability of the interphalangeal and metacarpo-phalangeal joints. The most frequent aesthetic problem is a deviation of the axis. Loss of mobility of the thumb seems to be of less importance.