Antibiofilm and antithrombotic hydrogel coating based on superhydrophilic zwitterionic carboxymethyl chitosan for blood-contacting devices

Blood-contacting devices must be designed to minimize the risk of bloodstream-associated infections, thrombosis, and intimal lesions caused by surface friction. However, achieving effective prevention of both bloodstream-associated infections and thrombosis poses a challenge due to the conflicting nature of antibacterial and antithrombotic activities, specifically regarding electrostatic interactions. This study introduced a novel biocompatible hydrogel of sodium alginate and zwitterionic carboxymethyl chitosan (ZW@CMC) with antibacterial and antithrombotic activities for use in catheters. The ZW@CMC hydrogel demonstrates a superhydrophilic surface and good hygroscopic properties, which facilitate the formation of a stable hydration layer with low friction. The zwitterionic-functionalized CMC incorporates an additional negative sulfone group and increased negative charge density in the carboxyl group. This augmentation enhances electrostatic repulsion and facilitates the formation of hydration layer. This leads to exceptional prevention of blood clotting factor adhesion and inhibition of biofilm formation. Subsequently, the ZW@CMC hydrogel exhibited biocompatibility with tests of in vitro cytotoxicity, hemolysis, and catheter friction. Furthermore, in vivo tests of antithrombotic and systemic inflammation models with catheterization indicated that ZW@CMC has significant advantages for practical applications in cardiovascular-related and sepsis treatment. This study opens a new avenue for the development of chitosan-based multifunctional hydrogel for applications in blood-contacting devices.

Early Left Ventricular Unloading or Conventional Approach After Venoarterial Extracorporeal Membrane Oxygenation: The EARLY-UNLOAD Randomized Clinical Trial

BACKGROUND

Although venoarterial extracorporeal membrane oxygenation (VA-ECMO) is beneficial for the treatment of profound cardiogenic shock, peripheral VA-ECMO cannulation can increase left ventricular afterload, thus compromising myocardial recovery. We investigated whether early routine left ventricular unloading can reduce 30-day mortality compared with the conventional approach in patients with cardiogenic shock undergoing VA-ECMO.

METHODS

This randomized clinical trial involved 116 patients with cardiogenic shock undergoing VA-ECMO from March 2021 to September 2022 at Chonnam National University Hospital, Gwangju, South Korea. The patients were randomly assigned to undergo either early routine left ventricular unloading with transseptal left atrial cannulation within 12 hours after randomization (n=58) or the conventional approach, which permitted rescue transseptal left atrial cannulation in case of an increased left ventricular afterload (n=58). The primary outcome was all-cause mortality within 30 days.

RESULTS

All 116 randomized patients (mean age, 67.6±13.5 years; 34 [29.3%] women) completed the trial. At 30 days, all-cause death had occurred in 27 (46.6%) patients in the early group and 26 (44.8%) patients in the conventional group (hazard ratio, 1.02 [95% CI, 0.59-1.74]; P=0.942). Crossover to rescue transseptal left atrial cannulation occurred in 29 patients (50%) in the conventional group according to a clear indication. Time to rescue transseptal cannulation in the conventional group was a median of 21.8 (interquartile range, 12.4-52.2) hours after randomization. There were no significant differences in other secondary outcomes between the 2 groups except for a shorter time to disappearance of pulmonary congestion in the early group (median, 3 [interquartile range, 2-6] versus 5 [interquartile range, 3-7] days; P=0.027).

CONCLUSIONS

Among patients with cardiogenic shock undergoing VA-ECMO, early routine left ventricular unloading with transseptal left atrial cannulation did not reduce 30-day mortality compared with the conventional strategy, which permitted rescue transseptal left atrial cannulation. These findings should be cautiously interpreted until the results of multicenter trials using other unloading modalities become available.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT04775472.

Early left ventricular unloading after extracorporeal membrane oxygenation: rationale and design of EARLY-UNLOAD trial

AIMS

The clinical benefits of venoarterial extracorporeal membrane oxygenation (VA-ECMO) for profound cardiogenic shock are well known. However, peripheral VA-ECMO increases the left ventricular afterload, thus compromising myocardial recovery. Recent studies have revealed the benefit of left ventricular unloading using various methods applied at different times. The EARLY-UNLOAD trial compares the clinical outcomes of early left ventricular unloading and conventional approach after VA-ECMO.

METHODS AND RESULTS

The EARLY-UNLOAD trial is a single-centre, open-label, randomized trial that recruited 116 patients with cardiogenic shock undergoing VA-ECMO. Patients meeting the inclusion criteria were randomized in a 1:1 ratio to two groups: routine left ventricular unloading via intracardiac echocardiography-guided transseptal left atrial cannulation within 12 h of VA-ECMO initiation or conventional approach that indicates rescue left ventricular unloading if clinical signs of an increased left ventricular afterload are present. The primary endpoint is the cumulative incidence of all-cause death within 30 days, and patients will be followed-up for 12 months. A key secondary endpoint is a composite measure of all-cause death and rescue transseptal left atrial cannulation in the conventional group (suggestive of VA-ECMO treatment failure) within 30 days. The enrolment of patients was finished in September 2022.

CONCLUSIONS

The EARLY-UNLOAD trial is the first randomized controlled trial to compare early left ventricular unloading and conventional approach after VA-ECMO using the same unloading modality. The results could impact clinical practice to overcome the haemodynamic issues associated with VA-ECMO.

Two Years of Experience and Methodology of Korean COVID-19 Living Clinical Practice Guideline Development

BACKGROUND

In Korea, during the early phase of the coronavirus disease 2019 (COVID-19) pandemic, we responded to the uncertainty of treatments under various conditions, consistently playing catch up with the speed of evidence updates. Therefore, there was high demand for national-level evidence-based clinical practice guidelines for clinicians in a timely manner. We developed evidence-based and updated living recommendations for clinicians through a transparent development process and multidisciplinary expert collaboration.

METHODS

The National Evidence-based Healthcare Collaborating Agency (NECA) and the Korean Academy of Medical Sciences (KAMS) collaborated to develop trustworthy Korean living guidelines. The NECA-supported methodological sections and 8 professional medical societies of the KAMS worked with clinical experts, and 31 clinicians were involved annually. We developed a total of 35 clinical questions, including medications, respiratory/critical care, pediatric care, emergency care, diagnostic tests, and radiological examinations.

RESULTS

An evidence-based search for treatments began in March 2021 and monthly updates were performed. It was expanded to other areas, and the search interval was organized by a steering committee owing to priority changes. Evidence synthesis and recommendation review was performed by researchers, and living recommendations were updated within 3-4 months.

CONCLUSION

We provided timely recommendations on living schemes and disseminated them to the public, policymakers and various stakeholders using webpages and social media. Although the output was successful, there were some limitations. The rigor of development issues, urgent timelines for public dissemination, education for new developers, and spread of several new COVID-19 variants have worked as barriers. Therefore, we must prepare systematic processes and funding for future pandemics.

Historical Review and Future of Cardiac Xenotransplantation

Along with the development of immunosuppressive drugs, major advances on xenotransplantation were achieved by understanding the immunobiology of xenograft rejection. Most importantly, three predominant carbohydrate antigens on porcine endothelial cells were key elements provoking hyperacute rejection: α1,3-galactose, SDa blood group antigen, and N-glycolylneuraminic acid. Preformed antibodies binding to the porcine major xenoantigen causes complement activation and endothelial cell activation, leading to xenograft injury and intravascular thrombosis. Recent advances in genetic engineering enabled knock-outs of these major xenoantigens, thus producing xenografts with less hyperacute rejection rates. Another milestone in the history of xenotransplantation was the development of co-stimulation blockaded strategy. Unlike allotransplantation, xenotransplantation requires blockade of CD40-CD40L pathway to prevent T-cell dependent B-cell activation and antibody production. In 2010s, advanced genetic engineering of xenograft by inducing the expression of multiple human transgenes became available. So-called 'multi-gene' xenografts expressing human transgenes such as thrombomodulin and endothelial protein C receptor were introduced, which resulted in the reduction of thrombotic events and improvement of xenograft survival. Still, there are many limitations to clinical translation of cardiac xenotransplantation. Along with technical challenges, zoonotic infection and physiological discordances are major obstacles. Social barriers including healthcare costs also need to be addressed. Although there are several remaining obstacles to overcome, xenotransplantation would surely become the novel option for millions of patients with end-stage heart failure who have limited options to traditional therapeutics.

Extracorporeal membrane oxygenation in adults receiving haematopoietic cell transplantation: an international expert statement

Combined advances in haematopoietic cell transplantation (HCT) and intensive care management have improved the survival of patients with haematological malignancies admitted to the intensive care unit. In cases of refractory respiratory failure or refractory cardiac failure, these advances have led to a renewed interest in advanced life support therapies, such as extracorporeal membrane oxygenation (ECMO), previously considered inappropriate for these patients due to their poor prognosis. Given the scarcity of evidence-based guidelines on the use of ECMO in patients receiving HCT and the need to provide equitable and sustainable access to ECMO, the European Society of Intensive Care Medicine, the Extracorporeal Life Support Organization, and the International ECMO Network aimed to develop an expert consensus statement on the use of ECMO in adult patients receiving HCT. A steering committee with expertise in ECMO and HCT searched the literature for relevant articles on ECMO, HCT, and immune effector cell therapy, and developed opinion statements through discussions following a Quaker-based consensus approach. An international panel of experts was convened to vote on these expert opinion statements following the Research and Development/University of California, Los Angeles Appropriateness Method. The Appraisal of Guidelines for Research and Evaluation statement was followed to prepare this Position Paper. 36 statements were drafted by the steering committee, 33 of which reached strong agreement after the first voting round. The remaining three statements were discussed by all members of the steering committee and expert panel, and rephrased before an additional round of voting. At the conclusion of the process, 33 statements received strong agreement and three weak agreement. This Position Paper could help to guide intensivists and haematologists during the difficult decision-making process regarding ECMO candidacy in adult patients receiving HCT. The statements could also serve as a basis for future research focused on ECMO selection criteria and bedside management.

Rapid remodeling observed at mid-term in-vivo study of a smart reinforced acellular vascular graft implanted on a rat model

BACKGROUND

The poor performance of conventional techniques used in cardiovascular disease patients requiring hemodialysis or arterial bypass grafting has prompted tissue engineers to search for clinically appropriate off-the-shelf vascular grafts. Most patients with cardiovascular disease lack suitable autologous tissue because of age or previous surgery. Commercially available vascular grafts with diameters of < 5 mm often fail because of thrombosis and intimal hyperplasia.

RESULT

Here, we tested tubular biodegradable poly-e-caprolactone/polydioxanone (PCL/PDO) electrospun vascular grafts in a rat model of aortic interposition for up to 12 weeks. The grafts demonstrated excellent patency (100%) confirmed by Doppler Ultrasound, resisted aneurysmal dilation and intimal hyperplasia, and yielded neoarteries largely free of foreign materials. At 12 weeks, the grafts resembled native arteries with confluent endothelium, synchronous pulsation, a contractile smooth muscle layer, and co-expression of various extracellular matrix components (elastin, collagen, and glycosaminoglycan).

CONCLUSIONS

The structural and functional properties comparable to native vessels observed in the neoartery indicate their potential application as an alternative for the replacement of damaged small-diameter grafts. This synthetic off-the-shelf device may be suitable for patients without autologous vessels. However, for clinical application of these grafts, long-term studies (> 1.5 years) in large animals with a vasculature similar to humans are needed.

Hyperglycemia and Hypoglycemia Are Associated with In-Hospital Mortality among Patients with Coronavirus Disease 2019 Supported with Extracorporeal Membrane Oxygenation

Metabolic abnormalities, such as preexisting diabetes or hyperglycemia or hypoglycemia during hospitalization aggravated the severity of COVID-19. We evaluated whether diabetes history, hyperglycemia before and during extracorporeal membrane oxygenation (ECMO) support, and hypoglycemia were risk factors for mortality in patients with COVID-19. This study included data on 195 patients with COVID-19, who were aged ≥19 years and were treated with ECMO. The proportion of patients with diabetes history among nonsurvivors was higher than that among survivors. Univariate Cox regression analysis showed that in-hospital mortality after ECMO support was associated with diabetes history, renal replacement therapy (RRT), and body mass index (BMI) < 18.5 kg/m2. Glucose at admission >200 mg/dL and glucose levels before ventilator >200 mg/dL were not associated with in-hospital mortality. However, glucose levels before ECMO >200 mg/dL and minimal glucose levels during hospitalization <70 mg/dL were associated with in-hospital mortality. Multivariable Cox regression analysis showed that glucose >200 mg/dL before ECMO and minimal glucose <70 mg/dL during hospitalization remained risk factors for in-hospital mortality after adjustment for age, BMI, and RRT. In conclusion, glucose >200 mg/dL before ECMO and minimal glucose level <70 mg/dL during hospitalization were risk factors for in-hospital mortality among COVID-19 patients who underwent ECMO.

Case Report: Fulminant Myocarditis Successfully Treated With Extracorporeal Membrane Oxygenation in Ikeda Strain Orientia tsutsugamushi Infection

Scrub typhus is an acute zoonotic febrile illness caused by Orientia tsutsugamushi having a specific geographic endemic area. This infection could be complicated with multi-organ involvement including myocarditis with variable severity. Here, we report a rare case of scrub typhus with biopsy-proven acute fulminant myocarditis which progressed very rapidly to cardiac arrest and was treated successfully with extracorporeal cardiopulmonary resuscitation. Clinicians should be alert to possible rapid progression of scrub typhus myocarditis to fulminant form and be prepared for close monitoring and temporary mechanical support if indicated.

The Outcome of Post-cardiotomy Extracorporeal Membrane Oxygenation in Neonates and Pediatric Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

Post-cardiotomy extracorporeal membrane oxygenation (PC-ECMO) is a known rescue therapy for neonates and pediatric patients who failed to wean from cardiopulmonary bypass (CPB) or who deteriorate in intensive care unit (ICU) due to various reasons such as low cardiac output syndrome (LCOS), cardiac arrest and respiratory failure. We conducted a systematic review and meta-analysis to assess the survival in neonates and pediatric patients who require PC-ECMO and sought the difference in survivals by each indication for PC-ECMO.

DESIGN

Systematic review and meta-analysis.

SETTING

Multi-institutional analysis.

PARTICIPANTS

Neonates and pediatric patients who requires PC- ECMO.

INTERVENTIONS

ECMO after open-heart surgery.

RESULTS

Twenty-six studies were included in the analysis with a total of 186,648 patients and the proportion of the population who underwent PC-ECMO was 2.5% (2,683 patients). The overall pooled proportion of survival in this population was 43.3% [95% Confidence interval (CI): 41.3-45.3%; I ²: 1%]. The survival by indications of PC-ECMO were 44.6% (95% CI: 42.6-46.6; I ²: 0%) for CPB weaning failure, 47.3% (95% CI: 39.9-54.7%; I ²: 5%) for LCOS, 37.6% (95% CI: 31.0-44.3%; I ²: 32%) for cardiac arrest and 47.7% (95% CI: 32.5-63.1%; I ²: 0%) for respiratory failure. Survival from PC-ECMO for single ventricle or biventricular physiology, was reported by 12 studies. The risk ratio (RR) was 0.74 for survival in patients with single ventricle physiology (95% CI: 0.63-0.86; I ²: 40%, P < 0.001). Eight studies reported on the survival after PC-ECMO for genetic conditions. The RR was 0.93 for survival in patients with genetic condition (95% CI: 0.52-1.65; I ²: 65%, P = 0.812).

CONCLUSIONS

PC-ECMO is an effective modality to support neonates and pediatric patients in case of failed CPB weaning and deterioration in ICU. Even though ECMO seems to improve survival, mortality and morbidity remain high, especially in neonates and pediatric patients with single ventricle physiology. Most genetic conditions alone should not be considered a contraindication to ECMO support, further studies are needed to determine which genetic abnormalities are associated with favorable outcome.

Case Report: Acute Fulminant Myocarditis and Cardiogenic Shock After Messenger RNA Coronavirus Disease 2019 Vaccination Requiring Extracorporeal Cardiopulmonary Resuscitation

Recently, myocarditis following messenger RNA (mRNA) coronavirus disease 2019 (COVID-19) vaccination has become an important social issue worldwide. According to the reports so far, myocarditis related to mRNA COVID-19 vaccination is rare and usually associated with a benign clinical course without intensive care or any sequelae of fulminant myocarditis. Here, we report a case of acute fulminant myocarditis and cardiogenic shock after the mRNA COVID-19 vaccination, requiring extracorporeal cardiopulmonary resuscitation. Clinicians should keep in mind the possibility of progression to fulminant myocarditis in patients who presented with suggestive symptoms or signs of myocarditis after the COVID-19 vaccination.

Acute Immune Response in Venoarterial and Venovenous Extracorporeal Membrane Oxygenation Models of Rats

Although experimental extracorporeal membrane oxygenation (ECMO) animal models have been reported, there are few studies on the immune response to ECMO. We developed the venoarterial (VA) and venovenous (VV) model in rats and serially investigated the changes in the distribution of immune cells. Forty rats underwent both VA and VV modes of ECMO, and blood samples were collected at 1 day before ECMO (D-1), at the end of ECMO run (D+0), and 3 days after the ECMO (D+3). Flow cytometry was used to characterize surface marker expression (CD3, CD4, CD8, CD43, CD45, CD45R, CD161, and His48) on immune cells. Granulocytes were initially activated in both ECMO types and were further reduced but not normalized until 3 days of decannulation. Monocyte and natural killer cells were decreased initially in VA mode. B lymphocytes, helper T lymphocytes, and cytotoxic T lymphocytes also significantly decreased in VA modes after ECMO, but this phenomenon was not prominent in the VV modes. Overall immune cells proportion changed after ECMO run in both modes, and the immunologic balance altered significantly in the VA than in VV mode. Our ECMO model is feasible for the hemodynamic and immunologic research, and further long-term evaluation is needed.

Application of low-strength ultrasonication to the continuous anaerobic digestion processes: UASBr and dry digester

In this study, the positive effects of low-strength ultrasonication (LS-ultrasonication) on the anaerobic digestion (AD) performance were investigated by continuously operating an upflow anaerobic sludge blanket reactor (UASBr) and a dry digester. In the ultrasonicated UASBr system (1 s per min, 0.05 W/mL), ultrasonication enhanced the CH₄ production by 38% and 19% in an ambient and a mesophilic condition, respectively. In addition, a different sludge yield and a changed electron flow were observed after ultrasonication. In the ultrasonicated dry digestion system (2 s per 30 s, 0.0025 W/mL), a 40% increase in the production of CH₄ was observed after lowering the total solid content of the reactor from 12% to 10%, implying that a high solid content diminished the ultrasonic stimulation effect. Moreover, the ultrasonication strength itself appeared to be a more crucial factor than the ultrasonication density during the application of LS-ultrasonication in the AD system.

Low strength ultrasonication positively affects the methanogenic granules toward higher AD performance. Part I: physico-chemical characteristics

To elucidate the correlation between enhanced biogas production and changed physico-chemical properties of methanogenic granules after low strength ultrasonication, in this study, the effects of low strength ultrasonication on the settling velocity, permeability, porosity, and fluid collection efficiency of the methanogenic granules were investigated. In addition, their morphological changes were visualized using a scanning electron microscopic technique. The experimental results indicate that low strength ultrasonication increased both the permeability (37%) and specific surface area (230%) of the granules through the generation of greater craters and cracks on the granular surface compared to the control granules. The penetration of nutrients and substrate into the granules was thereby enhanced, and more favorable conditions for achieving higher anaerobic performance were provided to the ultrasonicated granules. The microbial community shift caused by the changed physico-chemical properties of the methanogenic granules will be further analyzed in part II of this study.

Observation of reactor electron antineutrinos disappearance in the RENO experiment

The RENO experiment has observed the disappearance of reactor electron antineutrinos, consistent with neutrino oscillations, with a significance of 4.9 standard deviations. Antineutrinos from six 2.8  GW(th) reactors at the Yonggwang Nuclear Power Plant in Korea, are detected by two identical detectors located at 294 and 1383 m, respectively, from the reactor array center. In the 229 d data-taking period between 11 August 2011 and 26 March 2012, the far (near) detector observed 17102 (154088) electron antineutrino candidate events with a background fraction of 5.5% (2.7%). The ratio of observed to expected numbers of antineutrinos in the far detector is 0.920±0.009(stat)±0.014(syst). From this deficit, we determine sin(2)2θ(13)=0.113±0.013(stat)±0.019(syst) based on a rate-only analysis.

Pilomatrix Carcinoma in the Chest Wall Around an Eloesser Open Window - A case report -

Pilomatrix carcinoma originates in the matrix cell and is marked by exophytic growing and common local recurrence. There is no established treatment for wide local invasion and metastasis of the pilomatrix besides wide surgical resection. We report a case of rapidly progressive pilomatrix carcinoma, which arose around an Eloesser open window with direct invasion to the adjacent tissue.

Mid- to Long-term Results of Surgical Treatment of ASD in Patients over 60 Years Old

BACKGROUND

There is controversy about the benefit of surgical correction of an atrial septal defect (ASD) in patients over 60 years old. The purpose of this study was to determine whether surgical treatment is beneficial in those 60 years of age or older.

MATERIALS AND METHODS

We reviewed the clinical course of 57 patients (mean age: 63.54±5.59 years) diagnosed with an isolated secundum ASD after the age of 60. The 24 patients (group A) who underwent surgical repair were compared with the 33 patients (group B) who were treated non-surgically. The mean follow-up period was 6.8±4.5 years.

RESULTS

One operative death, 5 late deaths (20.8%) in group A, and 9 deaths (27.3%) in group B occurred in the study period. Symptomatic improvement was noted in 18 patients (75%) of group A after surgery. However 13 patients (39.4%) of group B showed symptomatic improvement during the follow-up period (p=0.012). The incidence of new atrial arrhythmia of the two groups was significantly different (16.7% vs 36.7%, p=0.038). The actuarial 10 year survival rate was 79% in group A and 73% in group B.

CONCLUSION

Although surgical correction of ASD did not increase survival in patients over 60 years old, the surgical outcomes of ASD showed low operative mortality and resulted in symptomatic improvement in the majority of these patients. This study has shown the benefits of surgical closure of ASD even in advanced age in comparison to medical treatment.

Electronic and structural characteristics of Zr-incorporated Gd2O3 films on strained SiGe substrates

Zr-incorporated Gd(2)O(3) films were grown on various substrates as a function of Zr content. The extent of interfacial reactions was found to be critically dependent on both the incorporated Zr content and the substrate type. Specifically, the silicide layer was suppressed and the Gd(2)O(3) phase was changed to ZrO(2) on a Si substrate with increasing Zr content. Crystalline Gd(2)Ge(2)O(7) was grown on a Ge substrate, as the result of interfacial reactions between Gd-oxide and the Ge substrate. However, interfacial reactions were not affected by the amount of Zr incorporated. On the SiGe/Si substrate, reactions between Gd-oxide and Si could be controlled effectively by the incorporation of Zr, while the extent of reactions with Ge was significantly enhanced as the Zr content increased. The formation of an interfacial layer between the film and the SiGe substrate resulted in a textured crystalline growth.

Improved search for nu(mu) --> nu(e) oscillation in a long-baseline accelerator experiment

We performed an improved search for nu(mu) --> nu(e) oscillation with the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment, using the full data sample of 9.2 x 10(19) protons on target. No evidence for a nu(e) appearance signal was found, and we set bounds on the nu(mu) --> nu(e) oscillation parameters. At Deltam(2)=2.8 x 10(-3) eV(2), the best-fit value of the K2Knu(mu) disappearance analysis, we set an upper limit of sin(2)2theta(mue) < 0.13 at a 90% confidence level.

Search for coherent charged pion production in neutrino-carbon interactions

We report the result from a search for charged-current coherent pion production induced by muon neutrinos with a mean energy of 1.3 GeV. The data are collected with a fully active scintillator detector in the K2K long-baseline neutrino oscillation experiment. No evidence for coherent pion production is observed, and an upper limit of is set on the cross section ratio of coherent pion production to the total charged-current interaction at 90% confidence level. This is the first experimental limit for coherent charged pion production in the energy region of a few GeV.

Evidence for muon neutrino oscillation in an accelerator-based experiment

We present results for nu(mu) oscillation in the KEK to Kamioka (K2K) long-baseline neutrino oscillation experiment. K2K uses an accelerator-produced nu(mu) beam with a mean energy of 1.3 GeV directed at the Super-Kamiokande detector. We observed the energy-dependent disappearance of nu(mu), which we presume have oscillated to nu(tau). The probability that we would observe these results if there is no neutrino oscillation is 0.0050% (4.0 sigma).

Induction of nitric oxide synthase by Oldenlandia diffusa in mouse peritoneal macrophages

Oldenlandia diffusa (OD) has been used to treat malignant tumors. In this study using mouse peritoneal macrophages, we have examined the mechanism by which OD regulates nitric oxide (NO) production. When OD (1 mg/ml) was used in combination with 10 U/ml of recombinant interferon-gamma (rIFN-gamma), there was a marked cooperative induction of NO production (36.13+/-7.12 microM) by the Griess method (nitrite). Treatment of macrophages with rIFN-gamma plus OD (1 mg/ml) caused a significant increase in tumor necrosis factor-alpha (TNF-alpha) production (4.49+/-1.43 ng/ml) by enzyme-linked immunosorbent assay. The increased production of NO and TNF-alpha from rIFN-gamma-plus OD-stimulated cells was almost completely inhibited by pretreatment with 100 microM of pyrrolidine dithiocarbamate (PDTC), an inhibitor of nuclear factor kappa B (NF-kappaB). PDTC also inhibited phosphorylation of IkappaB in rIFN-gamma-plus OD-stimulated cells. These findings demonstrate that OD increases the production of NO and TNF-alpha by rIFN-gamma-primed macrophages and suggest that NF-kappaB plays a critical role in mediating these effects of OD.