Double-blinded, randomised, placebo-controlled trial of convalescent plasma for COVID-19: analyses by neutralising antibodies homologous to recipients' variants

INTRODUCTION

Convalescent plasma (CP) emerged as potential treatment for COVID-19 early in the pandemic. While efficacy in hospitalised patients has been lacklustre, CP may be beneficial at the first stages of disease. Despite multiple new variants emerging, no trials have involved analyses on variant-specific antibody titres of CP.

METHODS

We recruited hospitalised COVID-19 patients within 10 days of symptom onset and, employing a double-blinded approach, randomised them to receive 200 ml convalescent plasma with high (HCP) or low (LCP) neutralising antibody (NAb) titre against the ancestral strain (Wuhan-like variant) or placebo in 1:1:1 ratio. Primary endpoints comprised intubation, corticosteroids for symptom aggravation, and safety assessed as serious adverse events. For a preplanned ad hoc analysis, the patients were regrouped by infused CP's NAb titers to variants infecting the recipients i.e. by titres of homologous HCP (hHCP) or LCP (hLCP).

RESULTS

Of the 57 patients, 18 received HCP, 19 LCP and 20 placebo, all groups smaller than planned. No significant differences were found for primary endpoints. In ad hoc analysis, hHCPrecipients needed significantly less respiratory support, and appeared to be given corticosteroids less frequently (1/14; 7.1%) than those receiving hLCP (9/23; 39.1%) or placebo (8/20; 40%), (p = 0.077).

DISCUSSION

Our double-blinded, placebo-controlled CP therapy trial remained underpowered and does not allow any firm conclusions for early-stage hospitalised COVID-19 patients. Interestingly, however, regrouping by homologous - recipients' variant-specific - CP titres suggested benefits for hHCP. We encourage similar re-analysis of ongoing/previous larger CP studies.

TRIAL REGISTRATION

ClinTrials.gov identifier: NCT0473040.

Adaptive wireless millirobotic locomotion into distal vasculature

Microcatheters have enabled diverse minimally invasive endovascular operations and notable health benefits compared with open surgeries. However, with tortuous routes far from the arterial puncture site, the distal vascular regions remain challenging for safe catheter access. Therefore, we propose a wireless stent-shaped magnetic soft robot to be deployed, actively navigated, used for medical functions, and retrieved in the example M4 segment of the middle cerebral artery. We investigate shape-adaptively controlled locomotion in phantoms emulating the physiological conditions here, where the lumen diameter shrinks from 1.5 mm to 1 mm, the radius of curvature of the tortuous lumen gets as small as 3 mm, the lumen bifurcation angle goes up to 120^°, and the pulsatile flow speed reaches up to 26 cm/s. The robot can also withstand the flow when the magnetic actuation is turned off. These locomotion capabilities are confirmed in porcine arteries ex vivo. Furthermore, variants of the robot could release the tissue plasminogen activator on-demand locally for thrombolysis and function as flow diverters, initiating promising therapies towards acute ischemic stroke, aneurysm, arteriovenous malformation, dural arteriovenous fistulas, and brain tumors. These functions should facilitate the robot’s usage in new distal endovascular operations.

Accessibility into the distal vascular systems to treat various diseases remains challenging using medical catheters. Here, Wang et al. demonstrate that a stent-shaped wireless magnetic soft robot enables adaptive locomotion and medical functions into these distal vascular regions.

Urethral cultures in patients with spinal cord injury

STUDY DESIGN

Prospective analysis.

OBJECTIVES

To investigate the colonization of the distal urethra and bladder during the initial stages of rehabilitation in acute spinal-cord injury (SCI) and to examine the association between bacteriuria and colonization of the distal urethra.

SETTING

Selcuk University Meram Faculty of Medicine, Konya, Turkey.

METHODS

A total of 27 patients with SCI (13 females and 14 males) and 40 controls without evidence of disease of the urinary tract were studied. Cultures were taken from the patients who applied clean intermittent catheterization and compared with normal subjects.

RESULTS

Escherichia coli was predominantly isolated from the urine and urethral cultures of both female and male SCI patients. Colonization of other bacteria in the urine and urethral cultures was similar in both female and male patients, except for Pseudomonas, which was colonized in male patients. In all, 72% of patients who had E. coli positive urethral cultures also had E. coli colonization in their simultaneous urine cultures. There was concordance between urethra and urine cultures concerning the growth of E. coli (P=0.82). When urethral cultures collected 1 week before were evaluated in patients with E. coli positive urine cultures (n=24 cultures), 15 of these urethral cultures also had E. coli colonization. There was concordance between urethra and urine cultures concerning the growth of E. coli (P=0.66).

CONCLUSIONS

Our study suggested that urethral flora was a significant source for the development of urinary infection in spinal cord-injured patients.