ABSTRACT
Background: Indications for therapeutic plasma exchange (TPE) in the pediatric intensive care unit (PICU) are expanding. We aimed to study the demographics, clinical indications, and outcomes of patients who have undergone TPE in our PICU. Materials and methods: This is a retrospective study performed among children aged from 1 month to 16 years of age. Demographics, indications, therapeutic response, serious adverse events (SAE), PICU length of stay (LOS), and death during hospitalization were studied as outcome variables. Results: Therapeutic plasma exchange was performed in 115 sessions on 24 patients for 12 different indications falling under various American Society for Apheresis (ASFA) categories. Therapeutic plasma exchange was performed on ten, four, and ten children for ASFA category I, II, and III indications, respectively. The most common indications were thrombotic microangiopathy (TMA) (8/24) and acute liver failure (ALF) (6/24). During those 115 sessions, a total of five serious adverse events (SAEs) occurred, accounting for 4.3% of the cases. Minor adverse events occurred in 12 sessions (10.4%). Therapeutic response was good in 17 patients (71%) including 5 patients who underwent standard volume TPE (SV-TPE) for ALF. Median PICU LOS was 9 (range 2-120) days. The mortality rate was 12.5% (3/24). Conclusion: Therapeutic plasma exchange is effective in various clinical conditions involving various organ systems. It is an excellent therapeutic modality in children with ALF, irrespective of the exchange volume and TMA. However, SAEs do occur in the minority. How to cite this article: Balasubramanian KK, Venkatachalapathy P, Margabandhu S, Natraj R, Sridaran VK, Lakshmanan C, et al. Scope, Safety, and Feasibility of Therapeutic Plasma Exchange in Pediatric Intensive Care Unit: A Single-center Experience. Indian J Crit Care Med 2023;27(10):766-770.
ABSTRACT
The production of bioactive peptides and small protein fragments is commonly achieved via solid-phase chemical synthesis. However, such techniques become unviable and prohibitively expensive when the peptides are large (e.g., >30 amino acids) or when isotope labeling is required for NMR studies. Expression and purification of large quantities of unfolded peptides in E. coli have also proved to be difficult even when the desired peptides are carried by fusion proteins such as GST. We have developed a peptide expression system that utilizes a novel fusion protein (SFC120) which is highly expressed and directs the peptides to inclusion bodies, thereby minimizing in-cell proteolysis whilst maintaining high yields of peptide expression. The expressed peptides can be liberated from the carrier protein by CNBr cleavage at engineered methionine sites or through proteolysis by specific proteases for peptides containing methionine residues. In the present systems, we use CNBr, due to the absence of methionine residues in the target peptides, although other cleavage sites can be easily inserted. We report the production of six unfolded protein fragments of different composition and lengths (19 to 48 residues) derived from the virulent effector kinases, Cla4 and Ste20 of Candida albicans. All six peptides were produced with high yields of purified material (30-40 mg/l in LB, 15-20 mg/l in M9 medium), pointing to the general applicability of this expression system for peptide production. The enrichment of these peptides with (15)N, (15)N/(13)C and even (15)N/(13)C/(2)H isotopes is presented allowing speedy assignment of poorly-resolved resonances of flexible peptides.
