Effect of school reopening on SARS-CoV-2 incidence in a low-prevalence region: Prospective SARS-CoV-2 testing in healthcare workers with primary school-attending children versus without children living at home.

Coronavirus disease 2019 (COVID-19) often presents asymptomatically or milder in children compared to adults. The role of young children in the transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) remains largely unknown. In the Netherlands, the first action of loosening the partial lockdown that had been implemented to reduce SARS-CoV-2 transmission was the reopening of primary schools on 1 May 2020.

Aggravation of fibrin deposition and microthrombus formation within the graft during kidney transplantation.

In kidney transplantation, microthrombi and fibrin deposition may lead to local perfusion disorders and subsequently poor initial graft function. Microthrombi are often regarded as donor-derived. However, the incidence, time of development, and potential difference between living donor kidneys (LDK) and deceased donor kidneys(DDK), remains unclear.

Organ-specific metabolic profiles of the liver and kidney during brain death and afterwards during normothermic machine perfusion of the kidney.

We investigated metabolic changes during brain death (BD) using hyperpolarized magnetic resonance (MR) spectroscopy and ex vivo graft glucose metabolism during normothermic isolated perfused kidney (IPK) machine perfusion. BD was induced in mechanically ventilated rats by inflation of an epidurally placed catheter; sham-operated rats served as controls. Hyperpolarized [1- C]pyruvate MR spectroscopy was performed to quantify pyruvate metabolism in the liver and kidneys at 3 time points during BD, preceded by injecting hyperpolarized[1- C]pyruvate.

Extended hypothermic oxygenated machine perfusion enables preservation of porcine livers for up to 24 hours.

Background & Aims: End-ischemic hypothermic oxygenated machine perfusion (HOPE) of the donor liver for 1-2 h mitigates ischemia-reperfusion injury during subsequent liver transplantation. Extended preservation time may be preferred to facilitate difficult recipient hepatectomy or to optimize logistics. We therefore investigated whether end-ischemic dual HOPE (DHOPE) could extend preservation time for up to 24 h using a porcine liver reperfusion model.

Peribiliary Glands Are Key in Regeneration of the Human Biliary Epithelium After Severe Bile Duct Injury.

Peribiliary glands (PBG) are a source of stem/progenitor cells organized in a cellular network encircling large bile ducts. Severe cholangiopathy with loss of luminal biliary epithelium has been proposed to activate PBG, resulting in cell proliferation and differentiation to restore biliary epithelial integrity. However, formal evidence for this concept in human livers is lacking.

Hypothermic oxygenated machine perfusion reduces bile duct reperfusion injury after transplantation of donation after circulatory death livers.

Dual hypothermic oxygenated machine perfusion (DHOPE) of the liver has been advocated as a method to reduce ischemia/reperfusion injury (IRI). This study aimed to determine whether DHOPE reduces IRI of the bile ducts in donation after circulatory death (DCD) liver transplantation. In a recently performed phase 1 trial, 10 DCD livers were preserved with DHOPE after static cold storage (SCS; www.

Normothermic machine perfusion of donor livers without the need for human blood products.

Normothermic machine perfusion (NMP) enables viability assessment of donor livers prior to transplantation. NMP is frequently performed by using human blood products including red blood cells (RBCs) and fresh frozen plasma (FFP). Our aim was to examine the efficacy of a novel machine perfusion solution based on polymerized bovine hemoglobin-based oxygen carrier (HBOC)-201.

Oxygenated hypothermic machine perfusion after static cold storage improves endothelial function of extended criteria donor livers.

Background: Lack of oxygen and biomechanical stimulation during static cold storage (SCS) of donor livers compromises endothelial cell function. We investigated the effect of end-ischemic oxygenated hypothermic machine perfusion (HMP) on endothelial cell function of extended criteria donor (ECD) livers.

Methods: Eighteen livers, declined for transplantation, were transported to our center using static cold storage (SCS).

Inadequate Antioxidative Responses in Kidneys of Brain-Dead Rats.

Background: Brain death (BD)-related lipid peroxidation, measured as serum malondialdehyde (MDA) levels, correlates with delayed graft function in renal transplant recipients. How BD affects lipid peroxidation is not known. The extent of BD-induced organ damage is influenced by the speed at which intracranial pressure increases.

Activation of Fibrinolysis, But Not Coagulation, During End-Ischemic Ex Situ Normothermic Machine Perfusion of Human Donor Livers.

Background: Ex situ normothermic machine perfusion (NMP) can be performed after traditional static cold preservation to assess graft function and viability before transplantation. It is unknown whether this results in activation of coagulation and fibrinolysis, as may occur upon graft reperfusion in vivo.

Methods: Twelve donor livers declined for transplantation underwent 6 hours of end-ischemic NMP using a heparinized plasma-based perfusion fluid.

Normothermic machine perfusion reduces bile duct injury and improves biliary epithelial function in rat donor livers.

Bile duct injury may occur during liver procurement and transplantation, especially in livers from donation after circulatory death (DCD) donors. Normothermic machine perfusion (NMP) has been shown to reduce hepatic injury compared to static cold storage (SCS). However, it is unknown whether NMP provides better preservation of bile ducts.

Oxygenated Hypothermic Machine Perfusion After Static Cold Storage Improves Hepatobiliary Function of Extended Criteria Donor Livers.

Background: The mechanism through which oxygenated hypothermic machine perfusion (HMP) improves viability of human extended criteria donor (ECD) livers is not well known. Aim of this study was to examine the benefits of oxygenated HMP after static cold storage (SCS).

Methods: Eighteen ECD livers that were declined for transplantation underwent ex situ viability testing using normothermic (37 °C) machine perfusion (NMP) after traditional SCS (0 °C-4 °C) for 7 to 9 hours.

Anti-Apoptotic Effects of 3,3',5-Triiodo-L-Thyronine in the Liver of Brain-Dead Rats.

Background: Thyroid hormone treatment in brain-dead organ donors has been extensively studied and applied in the clinical setting. However, its clinical applicability remains controversial due to a varying degree of success and a lack of mechanistic understanding about the therapeutic effects of 3,3',5-Triiodo-L-thyronine (T3). T3 pre-conditioning leads to anti-apoptotic and pro-mitotic effects in liver tissue following ischemia/reperfusion injury.

Diffuse reflectance spectroscopy accurately quantifies various degrees of liver steatosis in murine models of fatty liver disease.

Background: A real-time objective evaluation for the extent of liver steatosis during liver transplantation is currently not available. Diffuse reflectance spectroscopy (DRS) rapidly and accurately assesses the extent of steatosis in human livers with mild steatosis. However, it is yet unknown whether DRS accurately quantifies moderate/severe steatosis and is able to distinguish between micro- and macrovesicular steatosis.

End-ischemic machine perfusion reduces bile duct injury in donation after circulatory death rat donor livers independent of the machine perfusion temperature.

A short period of oxygenated machine perfusion (MP) after static cold storage (SCS) may reduce biliary injury in donation after cardiac death (DCD) donor livers. However, the ideal perfusion temperature for protection of the bile ducts is unknown. In this study, the optimal perfusion temperature for protection of the bile ducts was assessed.

Criteria for viability assessment of discarded human donor livers during ex vivo normothermic machine perfusion.

Although normothermic machine perfusion of donor livers may allow assessment of graft viability prior to transplantation, there are currently no data on what would be a good parameter of graft viability. To determine whether bile production is a suitable biomarker that can be used to discriminate viable from non-viable livers we have studied functional performance as well as biochemical and histological evidence of hepatobiliary injury during ex vivo normothermic machine perfusion of human donor livers. After a median duration of cold storage of 6.

Hypothermic oxygenated machine perfusion prevents arteriolonecrosis of the peribiliary plexus in pig livers donated after circulatory death.

Background: Livers derived from donation after circulatory death (DCD) are increasingly accepted for transplantation. However, DCD livers suffer additional donor warm ischemia, leading to biliary injury and more biliary complications after transplantation. It is unknown whether oxygenated machine perfusion results in better preservation of biliary epithelium and the peribiliary vasculature.

Are brain and heart tissue prone to the development of thiamine deficiency?

Thiamine deficiency is a continuing problem leading to beriberi and Wernicke's encephalopathy. The symptoms of thiamine deficiency develop in the heart, brain and neuronal tissue. Yet, it is unclear how rapid thiamine deficiency develops and which organs are prone to development of thiamine deficiency.

Static cold storage preservation of ischemically damaged kidneys. a comparison between IGL-1 and UW solution.

Especially in damaged organs, adequate organ preservation is critically important to maintain viability. Institut Georges Lopez-1 (IGL-1) is a new preservation solution, with an extracellular sodium/potassium ratio and polyethylene glycol as a colloid. The influence of warm and cold ischemia was evaluated in a rat Lewis-Lewis transplant model with a follow up of 14 days.

Determination of an adequate perfusion pressure for continuous dual vessel hypothermic machine perfusion of the rat liver.

Hypothermic machine perfusion (HMP) provides better protection against ischemic damage of the kidney compared to cold-storage. The required perfusion pressures needed for optimal HMP of the liver are, however, unknown. Rat livers were preserved in University of Wisconsin organ preservation solution enriched with acridine orange (AO) to stain viable cells and propidium iodide (PI) to detect dead cells.

Oxygenation during hypothermic rat liver preservation: an in vitro slice study to demonstrate beneficial or toxic oxygenation effects.

Hypothermic machine perfusion (HMP) of abdominal organs is shown to be superior compared to cold storage. However, the question remains if oxygenation is required during preservation as oxygen is essential for energy resynthesis but also generates toxic reactive oxygen species (ROS). To determine if oxygenation should be used during HMP, urea-synthesis rate, adenosine triphosphate (ATP), and generation of ROS were studied in an in vitro model, modeling ischemia-reperfusion injury.

Effect of brain death on gene expression and tissue activation in human donor kidneys.

Background: After kidney transplantation, decreased graft survival is seen in grafts from brain dead (BD) donors compared with living donors. This might result partly from a progressive nonspecific inflammation in the graft. In this study, we focused on the effects of BD on inflammatory response (adhesion molecules, leukocyte invasion, gene expression) and stress-related heat shock proteins in the human kidney.

Initial blood washout during organ procurement determines liver injury and function after preservation and reperfusion.

Organ procurement is the first step toward effective liver preservation and comprises a thorough washout of blood components from the microvasculature. To study the efficacy of optimal blood washout of the liver, three groups were compared including low-pressure perfusion with UW-CSS (12 mmHg, group A), which is the routine method in clinical practice, high-pressure perfusion with UW-CSS (100 mmHg, group B) and low-pressure perfusion with modified UW solution (12 mmHg, group C). After procurement all livers were preserved in original UW-CSS for 0, 24 or 48 h, followed by reperfusion in oxygenated Williams Medium E for 24 h at 37 degrees C.

Bone histomorphometry in children with newly diagnosed acute lymphoblastic leukemia.

The objective of this study was to obtain insight into bone formation and resorption in children with newly diagnosed untreated acute lymphoblastic leukemia (ALL). In 23 consecutive children with ALL, a bone biopsy was taken from the crista iliaca posterior under ketamine anesthesia, together with the diagnostic marrow aspiration, before any treatment was given. Histomorphometric assessment was done of bone volume, bone area, trabecular thickness, osteoid volume, osteoid area, osteoid width, number of osteoblasts, erosion area, and number of osteoclasts.