Successful renal transplantation in a family with a novel mutation in COL4A3 gene and autosomal recessive Alport syndrome

Alport syndrome (AS) is an inherited disorder of basement membranes caused by mutations affecting specific proteins of the type IV collagen family, presenting with nephropathy and extrarenal manifestations such as sensorineural deafness and ocular anomalies. Ten percentage to 15% of the patients with AS have autosomal recessive (ARAS) due to mutation in either COL4A3 or COL4A4 gene. We report a novel mutation in the COL4A3 gene in an Indian family with ARAS. The above‐mentioned genetic anomaly was a missense variation in exon 26 of the COL4A3 gene (chr2:228137797G>A; c.1891G>A) that resulted in the amino acid substitution of Arginine for Glycine at codon 631 (p.Gly631Arg) that was present in the heterozygous state in the asymptomatic parents and homozygous state in the male offspring who presented with early‐onset end‐stage renal disease, lenticonus and hearing loss. The patient (male offspring) underwent successful renal transplantation with his mother as a donor.     

Power Consumption of Rotary Blood Pumps: Pulsatile Versus Constant‐Speed Mode

We investigated the power consumption of a HeartMate III rotary blood pump based on in vitro experiments performed in a cardiovascular simulator. To create artificial‐pulse mode, we modulated the pump speed by decreasing the mean speed by 2000 rpm for 200 ms and then increasing speed by 4000 rpm (mean speeds plus 2000 rpm) for another 200 ms, creating a square waveform shape. The HeartMate III was connected to a cardiovascular simulator consisting of a hydraulic pump system to simulate left ventricle pumping action, arterial and venous compliance chambers, and an adjustable valve for peripheral resistance to facilitate the desired aortic pressure. The simulator operated based on Suga's elastance model to mimic the Starling response of the heart, thereby reproducing physiological blood flow and pressure conditions. We measured the instantaneous total electrical current and voltage of the pump to evaluate its power consumption. The aim was to answer these fundamental questions: (i) How does pump speed modulation affect pump power consumption? (ii) How does the power consumption vary in relation to external pulsatile flow? The results indicate that speed modulation and external pulsatile flow both moderately increase the power consumption. Increasing the pump speed reduces the impact of external pulsatile flow.