Hemolysis Index Research Articles

Investigation of an Acceptable Hemolysis Index Using Re-collected Samples

Investigation of an Acceptable Hemolysis Index Using Re-collected Samples

Zwitterionic functionalization of polysaccharide gum by graft copolymerization to develop 3-D network materials for anticancer drug delivery applications

Herein, functionalization of polysaccharide gum has been carried out to develop network copolymeric materials for use in sustained anticancer drug delivery. Grafting reaction of poly[2-(methacryloyloxy)ethyl] dimethyl-(3-sulfopropyl)ammonium hydroxide (MEDSAH) onto sterculia gum has been done in the presence of crosslinker. Copolymeric materials were characterized by scanning electron micrographs (SEMs), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), 13C-nuclear magnetic resonance (NMR), and thermogravimetric analysis (TGA). SEM, AFM and XRD displayed heterogeneous morphology with a rough surfaces of amorphous copolymeric materials. Peaks at 173.822 ppm (carbonyl carbon) and at 60.653 ppm (methylene carbon attached to a quaternary ammonium group) confirmed the addition of poly(MEDSAH) during the grafting reaction. Mesh size in network hydrogel was found between 14.54 nm to 36.32 nm. Sustained release of doxorubicin was found with non-Fickian diffusion and was best demonstrated by the kinetic model Hixson Crowell. The biocompatibility of material was revealed in a haemolytic index (1.74 ± 0.26%) less than two percent during the copolymer-blood interaction. The material exhibited antioxidant and mucoadhesion properties. Free radical scavenging ability of copolymers was 49.41 ± 0.97% in 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay of the antioxidant test. These properties of copolymeric hydrogels demonstrated their suitability for use in sustained drug delivery systems for cancer chemotherapy.

Development of the PSU Child Pump.

The Pennsylvania State University (PSU) Child Pump, a centrifugal continuous-flow ventricular assist device (cf-VAD), is being developed as a suitable long-term implantable device for pediatric heart failure patients between 10 and 35 kg, body surface area (BSA) of 0.5-1.2 m 2 , 1-11 years of age, and requiring a mean cardiac output of 1.0-3.5 L/min. In-vitro hydraulic and hemodynamic performances were evaluated on a custom mock circulatory loop with ovine blood. Normalized index of hemolysis (NIH) was evaluated under four conditions: 1) 8,300 rpm, 3.5 L/min, Δ P = 60 mm Hg, 2) 8,150 rpm, 5.1 L/min, Δ P = 20 mm Hg, 3) 8,400 rpm, 3.2 L/min, Δ P = 70 mm Hg, and 4) 9,850 rpm, 5.0 L/min, Δ P = 80 mm Hg, resulting in normalized index of hemolysis = 0.027 ± 0.013, 0.015 ± 0.006, 0.016 ± 0.008, and 0.026 ± 0.011 mg/dl, respectively. A mock fit study was conducted using a three-dimensional printed model of a 19 kg patient's thoracic cavity to compare the size of the PSU Child Pump to the HeartMate3 and the HVAD. Results indicate the PSU Child Pump will be a safer, appropriately sized device capable of providing the given patient cohort proper support while minimizing the risks of blood trauma as they wait for a transplant.

Hemolysis Index Correlations with Plasma-Free Hemoglobin and Plasma Lactate Dehydrogenase in Critically Ill Patients under Extracorporeal Membrane Oxygenation or Mechanical Circulatory Support-A Single-Center Study.

Monitoring for thrombosis and hemolysis is crucial for patients under extracorporeal or mechanical circulatory support, but it can be costly. We investigated correlations between hemolysis index (HI) and plasma-free hemoglobin (PFH) levels on one hand, and between the HI and plasma lactate dehydrogenase (LDH) levels on the other, in critically ill patients with and without extracorporeal or mechanical circulatory support. Additionally, we calculated the cost reductions if monitoring through HI were to replace monitoring through PFH or plasma LDH. In a single-center study, HI was compared with PFH and plasma LDH levels in blood samples taken for routine purposes in critically ill patients with and without extracorporeal or mechanical circulatory support. A cost analysis, restricted to direct costs associated with each measurement, was made for an average 10-bed ICU. This study included 147 patients: 56 patients with extracorporeal or mechanical circulatory support (450 measurements) and 91 patients without extracorporeal or mechanical circulatory support (562 measurements). The HI correlated well with PFH levels (r = 0.96; p < 0.01) and poorly with plasma LDH levels (r = 0.07; p < 0.01) in patients with extracorporeal or mechanical circulatory support. Similarly, HI correlated well with PFH levels (r = 0.97; p < 0.01) and poorly with plasma LDH levels (r = -0.04; p = 0.39) in patients without extracorporeal or mechanical circulatory support. ROC analyses demonstrated a strong performance of HI, with the curve indicating excellent discrimination in the whole cohort (area under the ROC of 0.969) as well as in patients under ECMO or mechanical circulatory support (area under the ROC of 0.988). Although the negative predictive value of HI for predicting PFH levels > 10 mg/dL was high, its positive predictive value was found to be poor at various cutoffs. A simple cost analysis showed substantial cost reduction if HI were to replace PFH or plasma LDH for hemolysis monitoring. In conclusion, in this cohort of critically ill patients with and without extracorporeal or mechanical circulatory support, HI correlated well with PFH levels, but poorly with plasma LDH levels. Given the high correlation and substantial cost reductions, a strategy utilizing HI may be preferable for monitoring for hemolysis compared to monitoring strategies based on PFH or plasma LDH. The PPV of HI, however, is unacceptably low to be used as a diagnostic test.

Formulation and evaluation of dissolving microneedle for transdermal delivery of piperine: the effect of polymers concentration

This research aims to develop the formulation of Dissolving Microneedle Piperine (DMNs PIP) and evaluate the effect of polymer concentration on characterisation and permeation testing results in ex vivo. DMNs PIP were prepared from varying concentrations of piperine (PIP) (10, 15, and 20% w/w) and polymers of polyvinyl alcohol (PVA): Polyvinyl pyrrolidone (30:60 and 60:25), respectively. Then the morphological evaluation of the formula was carried out, followed by mechanical strength testing. Furthermore, the density, LOD, and weight percentage of piperine in the dried microneedle were calculated and the determination of volume, needle weight and piperine weight and analysed. Ex vivo testing, X-Ray Diffraction, FTIR and hemolysis tests were carried out. PIP with PVA and PVP (F1) polymers produced DMN with mechanical strength (8.35 ± 0.11%) and good penetration ability. In vitro tests showed that the F1 polymer mixture gave good penetration (95.02 ± 1.42 μg/cm2), significantly higher than the F2, F3, F4, and F5 polymer mixtures. The DMNs PIP characterisation results through XRD analysis showed a distinctive peak in the 20–30 region, indicating the presence of crystals. The FTIR study showed that the characteristics of piperine found in DMNs PIP indicated that piperine did not undergo interactions with polymers. The results of the ex vivo study through DMNs PIP hemolytic testing showed no hemolysis occurred, with the hemolysis index below the 5% threshold reported in the literature. These findings indicate that DMNs PIP is non-toxic and safe to use as alternative for treating inflammation

Nanostructured Coatings Based on Graphene Oxide for the Management of Periprosthetic Infections.

To modulate the bioactivity and boost the therapeutic outcome of implantable metallic devices, biodegradable coatings based on polylactide (PLA) and graphene oxide nanosheets (nGOs) loaded with Zinforo™ (Zin) have been proposed in this study as innovative alternatives for the local management of biofilm-associated periprosthetic infections. Using a modified Hummers protocol, high-purity and ultra-thin nGOs have been obtained, as evidenced by X-ray diffraction (XRD) and transmission electron microscopy (TEM) investigations. The matrix-assisted pulsed laser evaporation (MAPLE) technique has been successfully employed to obtain the PLA-nGO-Zin coatings. The stoichiometric and uniform transfer was revealed by infrared microscopy (IRM) and scanning electron microscopy (SEM) studies. In vitro evaluation, performed on fresh blood samples, has shown the excellent hemocompatibility of PLA-nGO-Zin-coated samples (with a hemolytic index of 1.15%), together with their anti-inflammatory ability. Moreover, the PLA-nGO-Zin coatings significantly inhibited the development of mature bacterial biofilms, inducing important anti-biofilm efficiency in the as-coated samples. The herein-reported results evidence the promising potential of PLA-nGO-Zin coatings to be used for the biocompatible and antimicrobial surface modification of metallic implants.

A Novel Pumping Principle for a Total Artificial Heart.

Total artificial hearts (TAH) serve as a temporary treatment for severe biventricular heart failure. The limited durability and complication rates of current devices hamper long-term cardiac replacement. The aim of this study was to assess the feasibility of a novel valveless pumping principle for a durable pulsatile TAH (ShuttlePump). The pump features a rotating and linearly shuttling piston within a cylindrical housing with two in- and outlets. With a single moving piston, the ShuttlePump delivers pulsatile flow to both systemic and pulmonary circulation. The pump and actuation system were designed iteratively based on analytical and in silico methods, utilizing finite element methods (FEM) and computational fluid dynamics (CFD). Pump characteristics were evaluated experimentally in a mock circulation loop mimicking the cardiovascular system, while hemocompatibility-related parameters were calculated numerically. Pump characteristics cover the entire required operating range for a TAH, providing 2.5-9 L/min of flow rate against 50-160 mmHg arterial pressures at stroke frequencies of 1.5-5 Hz while balancing left and right atrial pressures. FEM analysis showed mean overall copper losses of 8.84 W, resulting in a local maximum blood temperature rise of <2 K. The CFD results of the normalized index of hemolysis were 3.57 mg/100 L, and 95% of the pump's blood volume was exchanged after 1.42 s. This study indicates the feasibility of a novel pumping system for a TAH with numerical and experimental results substantiating further development of the ShuttlePump.

Accurate correction model of blood potassium concentration in hemolytic specimens

Background and aimsThe results of blood potassium can be seriously affected by specimen hemolysis which may interfere with clinicians’ interpretation of test results. Redrawing blood and retesting may delay treatment time and it is not feasible for critically ill patients with difficulty in specimen collection. Therefore, it is significant to establish a mathematical model that can quickly correct the blood potassium concentration of hemolytic specimens. Materials and methodsThe residual blood samples from 107 patients at Peking University Third Hospital were collected to establish potassium correction model. Samples with different hemolysis indexes were obtained by ultrasonic crushing method. Blood potassium correction models of hemolysis specimens were established by linear regression and curve fitting using SPSS and MATLAB, respectively. In addition, blood samples from another 85 patients were used to verify the accuracy of the models and determine the optimal model. ResultsVariation of potassium (ΔK) was 0.003HI-0.03 (R2 = 0.9749) in linear regression model which had high correlation in ΔK and HI, and the correction formula was Kcorrection = Khemolysis-0.003 × HI + 0.03. Average rate of potassium change (αaverage) was 0.003 ± 0.0002 mmol/L in curve fitting model, and correction formula was Kcorrection = Khemolysis-0.003 × HI, and both men and women can use the same correction model. The accuracy of linear regression model was 96.5 %, and there was statistical difference between the verification results and the measured values (p < 0.05), while the accuracy of curve fitting model was 100 %, and there was no statistical difference between the verification results and the measured values (p = 0.552). The model was validated in an independent set of samples and all were within the TEa of 6 % and the accuracy of 100 %. ConclusionsBoth linear regression and curve fitting models of potassium correction had high accuracy, and can effectively correct the potassium concentration of hemolytic specimens, while the curve fitting model have superior accuracy.

“Eculizumab First” in the Management of Posttransplant Thrombotic Microangiopathy

IntroductionPost-transplant thrombotic microangiopathy (PT-TMA) is an uncommon event that characterizes approximately 3-14% of kidney transplants (KT), and that is associated with a higher risk of delayed graft function and graft loss. PT-TMA occurs more frequently within the first three months after transplant and can be a manifestation of de novo disease or the recurrence of previous atypical hemolytic uremic syndrome (aHUS). Abnormalities in complement regulation genes could explain the increased susceptibility of some patients to PT-TMA. Eculizumab is a humanized monoclonal antibody that inhibits the formation of the membrane attack complex C5b-9. The aim of this study is to evaluate the efficacy of eculizumab as treatment for PT-TMA. MethodsWe retrospectively analyzed clinical records of 45 KT patients who received eculizumab immediately after the clinical diagnosis of PT-TMA. ResultsKidney biopsy was performed in 91.1% of patients and complement genetic study in 64.4%. 85.4% of kidney biopsies showed signs of TMA; genetic analysis revealed one pathogenetic variant, two variants of uncertain significance, one likely benign variant, 8 risk polymorphisms, 27 risk haplotypes.After two weeks from the treatment starting, hemoglobin and platelets significantly increased. A remarkable improvement in kidney function was also observed. After six months, 28.8% of patients had a complete renal recovery while 44.4% had a partial recovery. ConclusionThis is, to our knowledge, the largest series of KT patients with PT-TMA treated with eculizumab. These data suggest that eculizumab is associated with a normalization of hemolysis indices and an important and progressive improvement of graft function.

Ischemia modified albumin as a marker of hypoxia in preterm infants in the first week after birth

BackgroundTissue hypoxia remains a leading cause of morbidity and mortality in preterm infants. Current biomarkers often detect irreversible hypoxic cellular injury (i.e. lactate) and are non-specific. A new biomarker is needed which detects tissue hypoxia before irreversible damage occurs. AimsTo investigate the relation between serum ischemia modified albumin (IMA), a marker of hypoxia; and analytic variables, patient related variables and conditions associated with hypoxia, in preterm infants. Study designRetrospective cohort study. SubjectsInfants with a gestational age < 30 weeks and/or birth weight < 1000 g. Outcome measuresWe collected two remnant blood samples in the first week after birth and measured IMA. IMA/albumin ratio (IMAR) was used to adjust for albumin. We assessed correlations between IMA(R) and analytic variables (albumin, lipemia- and haemolysis index); mean-2 h SpO2; mean-2 h variability of regional splanchnic oxygen saturation (rsSO2), measured using near-infrared spectroscopy; and patent ductus arteriosus (PDA). ResultsSixty-five infants were included. Albumin, the lipemia- and haemolysis index correlated negatively with IMA (r:-0.620, P<0.001; r:-0.458, P<0.001; and r:-0.337, P=0.002). IMAR correlated negatively with SpO2 (rho:-0.614, P<0.001). Lower rsSO2 variability correlated with higher IMAR values (rho:-0.785, n=14, P=0.001 and rho:-0.773, n=11, P=0.005). Infants with a hemodynamic significant PDA (hsPDA) had higher IMAR values than infants without PDA (0.13 [0.11–0.28], n=16 vs. 0.11 [0.08–0.20], n=29, P=0.005 and 0.11 [0.09–0.18], n=13 vs. 0.09 [0.06–0.17], n=37, P=0.026). ConclusionsWhen adjusted for albumin, the lipemia- and haemolysis index, IMAR has potential value as a marker for systemic hypoxia in preterm infants, considering the associations with SpO2, variability of rsSO2, and hsPDA.

Biocompatibility, anti-hemolytic, and antibacterial assessments of electrospun PCL/collagen composite nanofibers loaded with Acanthophora spicifera extracts mediated copper oxide nanoparticles

Research in the advancement of wound dressings strives to address specific issues related to infections, speed up the healing process, and enhance patient wellness, all of which will lead to improved wound care procedures. This study investigates the synthesis and characterization of electrospun Polycaprolactone (PCL)/Collagen (Col) nanofibers incorporated with Acanthophora spicifera extracts mediated copper oxide nanoparticles (CuO NPs) and to evaluate their biocompatibility, anti-hemolytic properties, and antibacterial efficacy. The synthesized copper oxide nanoparticles were spherical and 58 ± 17 nm in size as evidenced by the field emission scanning electron microscopy. The fiber diameter of PCL, PCL/Col, PCL/Col/CuO 1%, PCL/Col/CuO 2%, and PCL/Col/CuO 5% was found to be 373 ± 141 nm, 281 ± 46 nm, 221 ± 57 nm, 173 ± 40 and 162 ± 47 nm respectively. Contact angle measurements revealed that the addition of copper oxide nanoparticles into Polycaprolactone/Collagen nanofibers resulted in a decrease in water contact angle from 86.9° to 50.8°. The biocompatibility of the composite nanofibers was evaluated in vitro using mouse fibroblast cells. The results established that copper oxide-imbued nanofibers were non-toxic and biocompatible. The hemolytic index for PCL/Col, PCL/Col/CuO 1%, PCL/Col/CuO 2%, and PCL/Col/CuO 5% scaffolds was 0.91 ± 0.14, 0.76 ± 0.14, 1.21 ± 0.19, and 1.52 ± 0.08 % respectively which was below the permissible value. Furthermore, the PCL/Col/CuO 5% nanofibers exhibited bactericidal properties against Staphylococcus aureus, methicillin-resistant Staphylococcus aureus, and Escherichia coli. These findings suggest the potential applications of copper oxide-infused nanofibers in various biomedical fields, including tissue engineering, antimicrobial coatings, and wound healing.

Evaluation of Blood Cell Destruction by Measuring Occlusion Distance

Roller pumps are commonly used for electric motor-driven blood purification. Even the optimal occlusion for a roller pump is stimulated in JIS (Japanese Industrial Standard) -T1603, the blood cells can be destroyed if an applied pressure is too strong on the tube. On the other hand, the perfused blood volume might decrease if the pressure becomes weaker. Therefore, skilled operation is required. However, as there are no techniques to automatically measure occlusion, a highly reproducible method is urgently required to obtain an optimal setting. In this study, we classified the occlusion specified in JIS-T1603 into five categories (3, 6, 9, 12, and 15 drops/min) and measured those using a laser sensor. The distance between each occlusion was only a few microns. Based on the microscopic observation of the blood cell morphology at each occlusion, the blood cells with normal outlines were classified as normal blood cells, while those with protrusions were labeled as acanthocytes. Further, we calculated the normalized milligram index of hemolysis (mgNIH) to confirm hemolysis for each occlusion. By classifying occlusion into five categories and converting them into distances, we derived a safe, easy, and highly reproducible method.

Free hemoglobin determination at patients'bedside to evaluate hemolysis.

Background: The authors report the relevance of using a point of care test (Helge®) for free hemoglobin determination and concordance of the values the with Cobas® 8000 and spectrophotometer methods. Results: The within-run of the point of care test was <3%. Good correlations among the three methods were observed and an acceptable concordance for hemolysis index values from 50mg/dl. An excellent agreement between the Cobas8000 and the spectrophotometer was found. Conclusion: Automated methods represent methods of choice for free hemoglobin determination. An advantage of the Helgesystem is that it can be applied to samples experiencing a delay in evaluation due to the long distance between the collection site and the central laboratory. Another advantage is its use at the bedside, in the monitoring of extracorporeal membrane oxygenation patients.

Lactate dehydrogenase and hemolysis index to predict vaso-occlusive crisis in sickle cell disease

Sickle cell disease (SCD) is an inherited hemoglobinopathy disorder associated with chronic hemolysis. A major complication is vaso-occlusive crisis (VOC), associating frequent hospitalization, morbidity and mortality. The aim of this study was to investigate whether hemolysis biomarkers were able to predict VOC risk in adult patients with SCD requiring hospitalization within 1 year. This single-center prospective study included adult patients with SCD at steady state or during VOC. A total of 182 patients with SCD were included, 151 at steady state and 31 during VOC. Among the 151 patients at steady state 41 experienced VOC within 1 year (median: 3.0 months [2.0–6.5]). We observed an increase of lactate dehydrogenase (LDH) (p = 0.01) and hemolysis index (HI) (p = 0.0043) during VOC compared to steady state. Regarding patients with VOC requiring hospitalization, LDH (p = 0.0073) and HI (p = 0.04) were increased. In unadjusted logistic regression, LDH > median (> 260 U/L) (RR = 3.6 [1.29–10.88], p = 0.0098) and HI > median (> 8 UA/L) (RR = 3.13 [1.91–5.33]; p < 0.001) were associated with VOC. The association of LDH > 260 U/L and HI > 12 UA/L presented a sensitivity of 90%, and a specificity of 72.9% to predict VOC. The association of LDH and HI cut-off was able to predict VOC risk in SCD.

Triphenylphosphine Derivatives of Allylbenzenes Express Antitumor and Adjuvant Activity When Solubilized with Cyclodextrin-Based Formulations.

Allylbenzenes (apiol, dillapiol, myristicin and allyltetramethoxybenzene) are individual components of plant essential oils that demonstrate antitumor activity and can enhance the antitumor activity of cytotoxic drugs, such as paclitaxel, doxorubicin, cisplatin, etc. Triphenylphosphine (PPh3) derivatives of allylbenzenes are two to three orders of magnitude more potent than original allylbenzenes in terms of IC50. The inhibition of efflux pumps has been reported for allylbenzenes, and the PPh3 moiety is deemed to be responsible for preferential mitochondrial accumulation and the depolarization of mitochondrial membranes. However, due to poor solubility, the practical use of these substances has never been an option. Here, we show that this problem can be solved by using a complex formation with cyclodextrin (CD-based molecular containers) and polyanionic heparin, stabilizing the positive charge of the PPh3 cation. Such containers can solubilize both allylbenzenes and their PPh3 derivatives up to 0.4 mM concentration. Furthermore, we have observed that solubilized PPh3 derivatives indeed work as adjuvants, increasing the antitumor activity of paclitaxel against adenocarcinomic human alveolar basal epithelial cells (A549) by an order of magnitude (in terms of IC50) in addition to being quite powerful cytostatics themselves (IC50 in the range 1-10 µM). Even more importantly, CD-solubilized PPh3 derivatives show pronounced selectivity, being highly toxic for the A549 tumor cell line and minimally toxic for HEK293T non-tumor cells, red blood cells and sea urchin embryos. Indeed, in many cancers, the mitochondrial membrane is more prone to depolarization compared to normal cells, which probably explains the observed selectivity of our compounds, since PPh3 derivatives are known to act as mitochondria-targeting agents. According to the MTT test, 100 µM solution of PPh3 derivatives of allylbenzenes causes the death of up to 85% of A549 cancer cells, while for HEK293T non-cancer cells, only 15-20% of the cells died. The hemolytic index of the studied substances did not exceed 1%, and the thrombogenicity index was < 1.5%. Thus, this study outlines the experimental foundation for developing combined cytostatic medications, where effectiveness and selectivity are achieved through decreased concentration of the primary ingredient and the inclusion of adjuvants, which are safe or practically harmless substances.

Influence of pneumatic tube delivery system on laboratory results.

The pneumatic tube system (PTS) is an automated and fast modality of transportation of biological samples, but it has been reported to induce preanalytical errors. To study the influence of transportation by PTS on biochemistry tests which are particularly sensitive to haemolysis and atmospheric pressure variation. We compared laboratory results of arterial blood gas, sodium, potassium, chloride, lactate dehydrogenase, aspartate aminotransferase, alanine aminotransferase, glucose and haemolysis index of samples conveyed simultaneously by PTS and by courier. We recruited 30 patients from the sampling room and 40 patients from the intensive care unit. Transport through PTS resulted in a significant increase in aspartate aminotransferase and potassium without exceeding the limits of acceptability. Potassium was significantly more increased for samples transported in a higher speed line (p = .048) but without exceeding the limits of acceptability. No significant impact was noted on haemolysis indices. The pO2 variations due to PTS transportation exceeded the limit of acceptability with significant intra-individual variations. Our PTS is validated for biochemistry tests results. It reduces turnaround times without affecting sample quality. However, the interpretation of arterial blood gas results should be careful for samples transported by PTS.

The Role of Red Blood Cell Lifespan Testing in the Evaluation of Patients with Paroxysmal Nocturnal Hemoglobinuria

Objective To explore the role of red blood cell(RBC) lifespan testing in the evaluation of patients with paroxysmal nocturnal hemoglobinuria (PNH). Methods The endogenous breath carbon monoxide (CO) test was used to detect the RBC lifespan of PNH patient with the treatment of crovalimab（ Roche） or iptacopan（ Novartis.），for comparison of different hemolysis indices in the assessment of patients' condition. Results Nine patients have been enrolled in the study at our centre from June to December 2021, 4 with the treatment of crovalimab and 5 with iptacopan. The median lifespan in the untreated patients was 17 (range 12-38) days, median hemoglobin(Hb) 83(69-94) g/l, median lactic dehydrogenase（LDH）590.8(446.1-935.5)U/L, median PNH clones 96.0(33.2-99.9)%. By 6 months post-treatment, 8 patients achieved hematologic improvement without breakthrough hemolysis. In all patients, LDH levels decreased rapidly and stabilized at lower levels after starting treatment. But the degree of Hb recovery varied，median 60(20-85)g/L. Analyzing the correlation between different hemolytic indices (LDH, RBC lifespan, total bilirubin, indirect bilirubin, etc.) and Hb changes, RBC lifespan showed good correlation（P=0.002，R=0.867）. In the crovalimab group, three patients presented with a positive Coombs test and the negative patient didn't obtain hematologic improvement. No patients with a positive Coombs test were seen in the iptacopan group. Conclusion Different (upstream/downstream) complement inhibitors have different effects on the condition of PNH patients, and different indicators can reflect different results; LDH responds to intravascular hemolysis, and red blood cell lifespan also quantifies extravascular hemolysis, and is applied to monitor hemolysis. The application of RBC lifespan testing can provide an accurate scientific basis for the assessment of PNH conditions. Keywords: red blood cell lifespa, paroxysmal nocturnal hemoglobinuria ,red blood cell lifespan,lactic dehydrogenase

Anti-methicillin-resistant Staphylococcus aureus and antibiofilm activity of new peptides produced by a Brevibacillus strain.

Methicillin-resistant Staphylococcus aureus (MRSA) is listed as a highly prioritized pathogen by the World Health Organization (WHO) to search for effective antimicrobial agents. Previously, we isolated a soil Brevibacillus sp. strain SPR19 from a botanical garden, which showed anti-MRSA activity. However, the active substances were still unknown. The cell-free supernatant of this bacterium was subjected to salt precipitation, cation exchange, and reversed-phase chromatography. The antimicrobial activity of pure substances was determined by broth microdilution assay. The peptide sequences and secondary structures were characterized by tandem mass spectroscopy and circular dichroism (CD), respectively. The most active anti-MRSA peptide underwent a stability study, and its mechanism was determined through scanning electron microscopy, cell permeability assay, time-killing kinetics, and biofilm inhibition and eradication. Hemolysis was used to evaluate the peptide toxicity. The pure substances (BrSPR19-P1 to BrSPR19-P5) were identified as new peptides. Their minimum inhibition concentration (MIC) and minimum bactericidal concentration (MBC) against S. aureus and MRSA isolates ranged from 2.00 to 32.00 and 2.00 to 64.00 µg/mL, respectively. The sequence analysis of anti-MRSA peptides revealed a length ranging from 12 to 16 residues accompanied by an amphipathic structure. The physicochemical properties of peptides were predicted such as pI (4.25 to 10.18), net charge at pH 7.4 (-3 to +4), and hydrophobicity (0.12 to 0.96). The CD spectra revealed that all peptides in the water mainly contained random coil structures. The increased proportion of α-helix structure was observed in P2-P5 when incubated with SDS. P2 (NH2-MFLVVKVLKYVV-COOH) showed the highest antimicrobial activity and high stability under stressed conditions such as temperatures up to 100 °C, solution of pH 3 to 10, and proteolytic enzymes. P2 disrupted the cell membrane and caused bacteriolysis, in which its action was dependent on the incubation time and peptide concentration. Antibiofilm activity of P2 was determined by which the half-maximal inhibition of biofilm formation was observed at 2.92 and 4.84 µg/mL for S. aureus TISTR 517 and MRSA isolate 2468, respectively. Biofilm eradication of tested pathogens was found at the P2 concentration of 128 µg/mL. Furthermore, P2 hemolytic activity was less than 10% at concentrations up to 64 µg/mL, which reflected the hemolysis index thresholds of 32. Five novel anti-MRSA peptides were identified from SPR19. P2 was the most active peptide and was demonstrated to cause membrane disruption and cell lysis. The P2 activity was dependent on the peptide concentration and exposure time. This peptide had antibiofilm activity against tested pathogens and was compatible with human erythrocytes, supporting its potential use as an anti-MRSA agent in this post-antibiotic era.

Numerical Analysis of a Novel Rotating Piston Blood Pump Based on CFD

Currently, centrifugal and roller pumps are primarily used as ECMO blood pumps, but their high pressure or high shear force may lead to complications such as hemolysis and platelet activation. Thus, a new blood pump structure was designed by improving the rotating piston pump and applying it to the blood pump. The blood pump flow field was simulated using CFD simulation software to ensure that this pump can produce pulsatile blood flow and guarantee good distribution of flow velocity, pressure, and shear stress in the blood pump. The hemolysis value of the pump was calculated using the Lagrangian particle tracking method. The research results demonstrate that this pump has excellent hemodynamic performance and that most of the shear stresses are less than 100 Pa, as well as a small hemolysis index. Furthermore, the pump combines the advantages of pulsatile and non-pulsatile pumps. This newly developed pump is expected to provide a new direction for ECMO blood pump development and provides important evidence for further optimization and performance evaluation of rotating piston blood pumps.

Identification and Screening of Biosurfactant Producing Bacteria from Mechanic Workshops Soil in Gusau Metropolis, Nigeria

Biosurfactants are molecules that reduce interfacial tension. Their chemical composition can vary widely, but they have in common their amphiphilic or amphipatic nature and can thus be soluble in aqueous as well as in organic solvents. The study was carried out to identify and screen biosurfactant producing bacteria from mechanic workshops in Gusau metropolis. Eight (8) soil samples were collected at the depth of 0-7 and 8-15cm from selected mechanic workshops located at Gada Biyu, Taqama bye-pass, Birnin Ruwa and non-oil contaminated soil as control for analysis. The physicochemical parameters were analysed using standard procedures (blood heamolysis, drop collapse, oil displacement and emulsification index) methods were used to screen biosurfactant production by the isolates. Mineral salt medium supplemented with 1% Actual gasoline oil (AGO) as sole sources of carbon was used to isolate hydrocarbon degrading bacteria, while heterotrophic bacteria were isolated using nutrient Agar. The soil samples from the study area were characterised with smooth, grey to dark brown soil with an unpleasant smell as well as as well as high temperature and pH. The three mechanic workshops used for this study, shows relatively higher counts for Hydrocarbon Degrading Bacteria while higher heterotrophic bacterial count was obtained from the control site though there was no significant difference between individual mechanic workshop (p&gt;0.05). The isolates are potential biosurfactant producers based on their performance especially blood haemolysis and emulsification index. The isolates identified belonged to the species of Bacillus, Pseudomonas, Acinetobacter, Micrococcus and Serratia.