Discrepancy between arterial oxygen saturation and pulse oximetry measurement in a Chinese pediatric patient cohort.

Background: Increasing evidence suggest a racial bias in pulse oximetry measurement, but this was under investigated in Asian pediatric populations. Methods: Via the Pediatric Intensive Care database, this retrospective study included pediatric patient records of arterial oxygen saturation (SaO2) and oxygen saturation on pulse oximetry (SpO2) measured within 10 min. Discrepancy was examined, and potential predictors of occult hypoxemia (defined as SaO2 <88% with the paired SpO2 ≥92%) as well as its association with outcomes were explored by logistic regression. Results: A total of 390 patients were included with 454 pairs of SaO2-SpO2 readings. The study population consisted of Han Chinese (99.0%) and 43.6% were female. Occult hypoxemia was observed in 20.0% of the patients, with a mean SaO2 of 71.4 ± 15.8%. Potential predictors of occult hypoxemia included female, being first admitted to cardiac ICU, congenital heart disease, increased heart rate, while patients with prior surgery records were less likely to experience occult hypoxemia. Patients with occult hypoxemia had numerically higher in-ICU mortality (16.7% versus 10.9%) and in-hospital mortality (17.9% versus 10.9%), but the associations were not statistically significant. Conclusions: There was a substantial proportion of hypoxemia that was not detected by pulse oximetry in the Chinese pediatric patients, which might be predicted by several characteristics and seemed to associate with mortality.

Assessment of degradability and endothelialization of modified poly L-lactic acid (PLLA) atrial septal defect (ASD) occluders over time in vivo.

OBJECTIVE: To evaluate the fiber-degradation and endothelialization of a modified poly L-lactic acid (PLLA) atrial septal defect (ASD) occluder for a long time in vivo. METHODS: A total of 57 New Zealand rabbits were selected to establish the vasculature implantation model, which would be used to characterize the mechanical properties and pathological reaction of PLLA filaments (a raw polymer of ASD occluder). In total, 27 Experimental piglets were used to create the ASD model for the catheter implantation of PLLA ASD occluders. Then, X-ray imaging, transthoracic echocardiography, histopathology, and scanning electron microscope (SEM) were performed in the experimental animals at 3, 6, 12, and 24 months after implantation. RESULTS: In the rabbit models, the fibrocystic grade was 0 and the inflammatory response was grade 2 at 6 months after vasculature implantation of the PLLA filaments. The mass loss of PLLA filaments increased appreciably with the increasing duration of implantation, but their mechanical strength was decreased without broken. In the porcine models, the cardiac gross anatomy showed that all PLLA ASD occluders were stable in the interatrial septum without any vegetation or thrombus formation. At 24 months, the occluders had been embedded into endogenous host tissue nearly. Pathological observations suggested that the occluders degraded gradually without complications at different periods. SEM showed that the occluders were endothelialized completely and essentially became an integral part of the body over time. CONCLUSION: In the animal model, the modified PLLA ASD occluders exhibited good degradability and endothelialization in this long-term follow-up study.

The role and mechanism of histone lactylation in health and diseases.

Whether under anaerobic or aerobic conditions, glycolysis results in production of lactate. Increasing evidence suggests that lactate serves as a multifunctional signaling molecule that develops non-metabolic activities in addition to serving as a key metabolite to link glycolysis and oxidative phosphorylation. Histone posttranslational modification patterns (HPTMs) are essential epigenetic processes controlling a variety of biological activities. Proteomics based on mass spectrometry (MS) has been used to progressively reveal new HPTMs. Recent discoveries of histone lactylation modification mediated by lactate and subsequent research demonstrating its involvement in cancer, inflammation, lung fibrosis, and other conditions suggest that it plays a significant role in immune regulation and homeostasis maintenance. This review provides a brief overview of the complicated control of histone lactylation modification in both pathological and physiological conditions.

Function and mechanism of histone ß-hydroxybutyrylation in health and disease.

Histone post-translational modifications (HPTMs) are essential epigenetic mechanisms that affect chromatin-associated nuclear processes without altering the DNA sequence. With the application of mass spectrometry-based proteomics, novel histone lysine acylation, such as propionylation, butyrylation, crotonylation, malonylation, succinylation, glutarylation, and lactoylation have been successively discovered. The emerging diversity of the lysine acylation landscape prompted us to investigate the function and mechanism of these novel HPTMs in health and disease. Recently, it has been reported that ß-hydroxybutyrate (BHB), the main component of the ketone body, has various protective roles beyond alternative fuel provision during starvation. Histone lysine ß-hydroxybutyrylation (Kbhb) is a novel HPTMs identified by mass spectrometry, which regulates gene transcription in response to carbohydrate restriction or elevated BHB levels in vivo and vitro. Recent studies have shown that histone Kbhb is strongly associated with the pathogenesis of metabolic cardiovascular diseases, kidney diseases, tumors, neuropsychiatric disorders, and metabolic diseases suggesting it has different functions from histone acetylation and methylation. This review focuses on the writers, erasers, sites, and underlying functions of histone Kbhb, providing a glimpse into their complex regulation mechanism.

Initial status and 3-month results relating to the use of biodegradable nitride iron stents in children and the evaluation of right ventricular function.

Background: Pulmonary artery stenosis is often associated with congenital heart disease. The aim of the study was to evaluate the efficacy and safety of stenting for branch pulmonary artery stenosis using a biodegradable nitride iron stent (IBS® Angel™) and right ventricular systolic and diastolic function. Methods: From July 2021 to February 2022, a total of 11 cases (ages ranged from 36 to 86 months old) were included in this pre and post-intervention, prospective, cohort and preclinical study. All cases underwent transthoracic echocardiographic (TTE), chest radiography, along with computed tomography (256-slice scanner, multiple-detector) and right heart catheterization. Different types of biodegradable nitride iron stents were implanted. TTE was performed serially 1 day, 1 month and 3 months after the procedure to evaluate the rate of restenosis and right ventricular function. Results: Stenting was successful in 11 patients. There were no major adverse cardiovascular events related to the device or to the procedure. Blood perfusion in the branch pulmonary artery was improved immediately. At follow-up, there was no significant restenosis that required re-intervention. None of the patients suffered from in-stent thrombosis, vascular embolism, stent displacement or heart failure. Compared with normal values, there were statistical with regards to FAC, E/A and E'/A'. Furthermore, we found that TAPSE correlated significantly with pulsed Doppler S wave (p = 0.008) and left ventricular ejection fraction (p < 0.01). The early trans-tricuspid inflow velocities E/E' (tissue doppler at the lateral tricuspid annulus) correlated significantly with E'/A' (p = 0.009). FAC and E'/A' were statistically different from those prior to stenting (p = 0.041 and p = 0.035) when tested one month postoperatively. At three months postoperatively, only E/A showed a statistical difference (p = 0.015). Conclusion: Our analysis suggests that biodegradable nitride iron stents are feasible, safe, and effective in children. Some small improvements were observed in right ventricular systolic and diastolic function after successful transcatheter intervention, although change was not statistically significant due to the small sample number. (A clinical Trial to Evaluate the Safety and Efficacy of IBS Angel in Patients With Pulmonary Artery Stenosis (IRIS); NCT04973540).

Cardiovascular Abnormalities and Gene Mutations in Children With Noonan Syndrome.

Background: Common cardiac abnormalities in Noonan syndrome (NS) include congenital heart diseases (CHD), pulmonary valve stenosis and hypertrophic cardiomyopathy (HCM). Molecular diagnoses are enabling earlier and more precise diagnosis of patients who have a subtle or atypical presentation. The aims of this study were to investigate genotype-phenotype associations with respect to Noonan syndrome (NS)-associated cardiac abnormalities and catheter or surgery-based interventions conditions. Methods: From January 2019 to December 2021, 22 children with a confirmed molecular diagnosis of NS combined with cardiovascular abnormalities were consecutively enrolled into the current study. A comprehensive review was carried out of echocardiography and electrocardiogram results, second-generation whole-exome sequencing results and catheter or surgery-based interventions conditions. Results: The main manifestations of electrocardiogram abnormalities were QTc prolongation, abnormal Q wave in the precordial lead and limb lead, right ventricular hypertrophy and left or right deviation of the electrical axis. The most commonly detected abnormality was pulmonary valve dysplasia with stenosis, seen in 15 (68.2%) patients, followed by atrial septal defect in 11 (50%) patients. Seven genes (RAF1, RIT1, SOS1, PTPN11, BRAF, SOS2, and LZTR1) were found to contain disease-associated variants. The most commonly observed genetic mutations were PTPN11 (27%) and RAF1 (27%). Each genotype was associated with specific phenotypic findings. RIT1, SOS1, PTPN11, and SOS2 had common echocardiography features characterized by pulmonary valve stenosis, while RAF1 was characterized by HCM. Interestingly, patients with BRAF mutations were not only characterized by HCM, but also by pulmonary valve stenosis. In the cohort there was only one patient carrying a LZTR1 mutation characterized by left ventricle globose dilation. Ten cases underwent catheter or surgery-based interventions. All the operations had immediate results and high success rates. However, some of the cases had adverse outcomes during extended follow-up. Based on the genotype-phenotype associations observed during follow-up, BRAF and RAF1 genotypes seem to be poor prognostic factors, and multiple interventions may be required for NS patients with severe pulmonary stenosis or myectomy for HCM. Conclusions: The identification of causal genes in NS patients has enabled the evaluation of genotype-cardiac phenotype relationships and prognosis of the disease. This may be beneficial for the development of therapeutic approaches.

Predictors of operability in children with severe pulmonary hypertension associated with congenital heart disease.

BACKGROUND: Pulmonary artery hypertension associated with congenital heart disease (PAH-CHD) occurs predominantly among patients with uncorrected CHD. Treatment of severe pediatric PAH-CHD remains a major intractability. This study evaluated the predictors and prognoses of children with PAH-CHD who underwent surgical correction. METHODS: The data for 59 children with severe PAH-CHD who underwent surgical correction, with or without postoperative medication, between May 2011 and June 2015 at the Guangdong Provincial People's Hospital were analyzed retrospectively. A regression analysis, receiver-operating characteristic (ROC) curves, and Kaplan-Meier curves were used for survival analysis. RESULTS: Fifty-nine children with severe PAH-CHD underwent heart catheterization and correction, with or without specific anti-PAH drugs postoperatively, were included in this study. The pulmonary pressure, heart function, and ending events were observed and median observation period was 49 ±â€Š20 months. Twenty-eight patients (50%) received at least one additional anti-PAH drug after correction. The survival rate after 2 years was 91.5% (54/59); two patients were in a critical condition, and three were lost to follow-up. Twelve patients (29%) still received over one additional PAH-specific therapy at follow-up, whereas 42 (75%) had successfully stopped drug treatment. Two patients (3.5%) died and one underwent a second thoracotomy to remove the ventricular septal defect patch. Acute vasoreactivity test (AVT) criteria had limited efficacy in predicting pediatric PAH-CHD, whereas pulmonary vascular resistance (PVR) ≤ 6.65 Wood units (WU)/m or PVR/systemic vascular resistance (SVR) ≤ 0.39 during AVT indicated a good prognosis after surgical correction with an AUC of 98.3% (95% confidence interval [CI]: 96.0-100%), 98.4% (95% CI: 96.0-100%) sensitivity of 100%, 100% and specificity of 82.1%, 92.9%, respectively. CONCLUSIONS: Although the criteria for positive AVT currently used are unsuitable for pediatric patients with PAH-CHD, PVR and PVR/SVR during AVT are excellent predictors of outcome in pediatric PAH-CHD. Surgery aided by anti-PAH drugs is an effective strategy and should be recommended for severe pediatric PAH-CHD with PVR ≤ 6.65 WU/m and PVR/SVR ≤ 0.39 after iloprost aerosol inhalation.

Physical properties and antioxidant capacity of chitosan/epigallocatechin-3-gallate films reinforced with nano-bacterial cellulose.

Films with antioxidant activity were prepared by combining chitosan (CH) and epigallocatechin-3-gallate (EGCG) with nano-bacterial cellulose (BC) as a reinforcement agent. Results showed that BC addition improved the qualities of films jeopardized by EGCG. Fourier Transform Infrared (FTIR) spectroscopy analysis confirmed that there were intermolecular interactions among BC, CH and EGCG though hydrogen bonding. Consequently, BC addition increased the crystallinity and thermal stability of CH-BC5/10-EGCG15/30 films analyzed by X-ray diffraction (XRD) and thermogravimetric (TGA) analysis. BC addition also significantly decreased water solubility (WS), from 26.54% to 20.80%, increased tensile strength (TS), from 18.71 to 44.17MPa, and increased elongation at break (EAB), from 2.72% to 7.34%. Moreover, BC and EGCG had high affinity for each other, as BC addition lowered the release of EGCG from CH films with a higher ABTS radical scavenging ability. Therefore, BC can be used as a sustained release carrier of EGCG in antioxidant active films.

Shifts in oxidation states of cerium oxide nanoparticles detected inside intact hydrated cells and organelles.

Cerium oxide nanoparticles (CNPs) have been shown to induce diverse biological effects, ranging from toxic to beneficial. The beneficial effects have been attributed to the potential antioxidant activity of CNPs via certain redox reactions, depending on their oxidation state or Ce(3+)/Ce(4+) ratio. However, this ratio is strongly dependent on the environment and age of the nanoparticles and it is unclear whether and how the complex intracellular environment impacts this ratio and the possible redox reactions of CNPs. To identify any changes in the oxidation state of CNPs in the intracellular environment and better understand their intracellular reactions, we directly quantified the oxidation states of CNPs outside and inside intact hydrated cells and organelles using correlated scanning transmission x-ray and super resolution fluorescence microscopies. By analyzing hundreds of small CNP aggregates, we detected a shift to a higher Ce(3+)/Ce(4+) ratio in CNPs inside versus outside the cells, indicating a net reduction of CNPs in the intracellular environment. We further found a similar ratio in the cytoplasm and in the lysosomes, indicating that the net reduction occurs earlier in the internalization pathway. Together with oxidative stress and toxicity measurements, our observations identify a net reduction of CNPs in the intracellular environment, which is consistent with their involvement in potentially beneficial oxidation reactions, but also point to interactions that can negatively impact the health of the cells.

Toxicity of nickel ions and comprehensive analysis of nickel ion-associated gene expression profiles in THP-1 cells.

The aim of the present study was to explore the toxic effects and underlying mechanisms of nickel ions during therapeutic nickel­based alloy­treatment in congenital heart disease by investigating the metal­induced cytotoxicity to the human monocyte­derived macrophage cell line THP­1. THP­1 cells were treated with NiCl2·6H2O (25, 50, 100, 200, 400 and 800 µM) for 24, 48 and 72 h, respectively. MTT was applied to detect THP­1 cell proliferation following NiCl2 treatment. Apoptosis of THP­1 cells was quantified using flow cytometry. Illumina sequencing was used for screening the associated genes, whose mRNA expression levels were further confirmed by quantitative real­time polymerase chain reaction. High concentrations of nickel ions had a significant suppressive effect on cell proliferation at the three concentrations investigated (200, 400 and 800 µM). Treatment with nickel ions (25­400 µM) for 48 h reduced cell viability in a dose­dependent manner. The mRNA expression levels of RELB, FIGF, SPI­1, CXCL16 and CRLF2 were significantly increased following nickel treatment. The results of the present study suggested that nickel ions exert toxic effects on THP­1 cell growth, which may indicate toxicity of the nickel ion during treatment of congenital heart disease. The identification of genes modified by the toxic effects of nickel on THP­1 cells (EPOR, RELB, FIGF, SPI­1, TGF­ß1, CXCL16 and CRLF2) may aid in the development of interventional measures for the treatment/prevention of nickel ion­associated toxic effects during the treatment of congenital heart disease.

Intracellular accumulation dynamics and fate of zinc ions in alveolar epithelial cells exposed to airborne ZnO nanoparticles at the air-liquid interface.

Airborne nanoparticles (NPs) that enter the respiratory tract are likely to reach the alveolar region. Accumulating observations support a role for zinc oxide (ZnO) NP dissolution in toxicity, but the majority of in-vitro studies were conducted in cells exposed to NPs in growth media, where large doses of dissolved ions are shed into the exposure solution. To determine the precise intracellular accumulation dynamics and fate of zinc ions (Zn(2+)) shed by airborne NPs in the cellular environment, we exposed alveolar epithelial cells to aerosolized NPs at the air-liquid interface (ALI). Using a fluorescent indicator for Zn(2+), together with organelle-specific fluorescent proteins, we quantified Zn(2+) in single cells and organelles over time. We found that at the ALI, intracellular Zn(2+) values peaked 3 h post exposure and decayed to normal values by 12 h, while in submerged cultures, intracellular Zn(2+) values continued to increase over time. The lowest toxic NP dose at the ALI generated peak intracellular Zn(2+) values that were nearly three-folds lower than the peak values generated by the lowest toxic dose of NPs in submerged cultures, and eight-folds lower than the peak values generated by the lowest toxic dose of ZnSO4 or Zn(2+). At the ALI, the majority of intracellular Zn(2+) was found in endosomes and lysosomes as early as 1 h post exposure. In contrast, the majority of intracellular Zn(2+) following exposures to ZnSO4 was found in other larger vesicles, with less than 10% in endosomes and lysosomes. Together, our observations indicate that low but critical levels of intracellular Zn(2+) have to be reached, concentrated specifically in endosomes and lysosomes, for toxicity to occur, and point to the focal dissolution of the NPs in the cellular environment and the accumulation of the ions specifically in endosomes and lysosomes as the processes underlying the potent toxicity of airborne ZnO NPs.

Role of Nogo­A in the regulation of hepatocellular carcinoma SMMC­7721 cell apoptosis.

Nogo-A has been identified as an inhibitor of neurite outgrowth specific to the central nervous system. However, little is known about the role of Nogo-A in hepatocellular carcinoma (HCC), the most common primary malignant tumor with a high mortality rate. This study aimed to investigate the role of endogenous Nogo-A in human liver cancer cells. Reverse transcription polymerase chain reaction was used to detect the expression of Nogo-A in four liver cancer cell lines. A lentivirus vector was then constructed to mediate RNA interference (RNAi) targeting of Nogo­A (LV­Nogo-A­siRNA) and was confirmed to successfully suppress the expression of the Nogo-A gene in SMMC-7721 cells. Furthermore, Nogo-A was observed to be highly expressed in liver cancer cell lines. RNAi of Nogo-A using the LV­Nogo-A­siRNA construct significantly decreased Nogo-A protein expression and specifically inhibited the growth of SMMC-7721 cells. This growth inhibitory effect may be attributed to an increase in G2/M phase arrest and apoptosis in SMMC-7721 cells containing Nogo-A­siRNA. The results of this study demonstrate that Nogo-A may represent a novel therapeutic target for the treatment of liver cancer, in addition to its potent roles in neural systems.

Potential biomarkers predicting risk of pulmonary hypertension in congenital heart disease: the role of homocysteine and hydrogen sulfide.

BACKGROUND: Pulmonary hypertension (PH) is a common complication of congenital heart disease (CHD). Although risk stratification is vital for prognosis and therapeutic guidance, the need for understanding the role of novel biomarkers cannot be overlooked. The aim of the present study was to investigate the changes of homocysteine and hydrogen sulfide levels and find potential biomarkers for early detection and treatment. METHODS: Between September 2012 and April 2013, we prospectively collected data on 158 pediatric patients with left to right shunt CHD at our institution. Standard right heart catheterizations were performed in all cases. Seventy-seven cases were associated with PH. The levels of homocysteine and hydrogen sulfide were detected with fluorescence polarization immunoassay and a sensitive silver-sulphur electrode, respectively. Enzyme-linked immunosorbent assay was used to determine the expression of methylenetetrahydrofolate reductase (MTHFR), cystathionine ß-synthase (CBS), and cystathionine gamma-lyase (CSE). Radioimmunoassays were used to obtain folic acid and vitamin B12 levels. RESULTS: The difference in the levels of homocysteine, folic acid, vitamin B12, hydrogen sulfide, as well as the MTHFR and CSE expression between patients with PH and without PH were statistically significant (all P < 0.05). Homocysteine had the best sensitivity and specificity to predict PH (P < 0.001). Subgroup analysis showed that the levels of homocysteine and hydrogen sulfide, and the expression of CSE and MTHFR between patients with dynamic and obstructive PH were significantly different (all P < 0.05). Based on the ROC curve, homocysteine had the best sensitivity and specificity to predict obstructive PH (P = 0.032), while CSE had the most significant sensitivity and specificity to predict the dynamic PH (P = 0.008). CONCLUSIONS: Increased levels of homocysteine and decreased levels of hydrogen sulfide were significantly negatively correlated in PH associated with CHD. The underlying mechanism involved the decreased expression of MTHFR and CSE along with vitamin B12 deficiency. Homocysteine and hydrogen sulfide are potential biomarkers to predict PH.

[Peripheral blood CD4⁺;CXCR5⁺; follicular helper T cells are related to hyperglobulinemia of patients with chronic hepatitis B].

OBJECTIVE: To detect cell frequency and surface markers of peripheral blood CD4⁺;CXCR5⁺;follicular helper T cells (Tfh cells) and analyze the correlation between CD4⁺;CXCR5⁺;Tfh cells and hyperglobulinemia of patients with chronic hepatitis B. METHODS: We collected blood samples of 20 HBV infected patients with hyperglobulinemia, 10 chronic HBV infected patients and 10 health volunteers and isolated plasma and peripheral blood mononuclear cells (PBMCs). The percentage of CD4⁺;CXCR5⁺;Tfh cells and the expressions of PD-1, ICOS and CD40L on CD4⁺;CXCR5⁺;Tfh cells were detected by flow cytometry. The levels of CXCL13, IFN-γ and IL-21 in plasma were measured by ELISA. RESULTS: Compared with the percentage of CD4⁺;CXCR5⁺;Tfh cells in chronic HBV infected patients (11.9 ± 3.9) and health controls (6.8 ± 3.9), it was higher in HBV infected patients with hyperglobulinemia (22.6 ± 4.7, P<0.05). And in the hyperglobulinemia patients, the expressions of PD-1 and CD40L on CD4⁺;CXCR5⁺;Tfh cells and the levels of CXCL13 and IL-21 in plasma increased, whereas the level of IFN-γ significantly declined (P<0.05). CONCLUSION: The results suggest that CD4⁺;CXCR5⁺;Tfh cells may participate in the pathogenesis of hyperglobulinemia during HBV infection.

[Peg-IFNa-2a/RBV antiviral efficacy in cirrhotic hepatitis C patients after splenectomy or partial splenic embolization].

To investigate the antiviral efficacy of combination therapy with pegylated-interferon alpha (peg-IFNa)-2a and ribavirin (RBV) in hepatitis C patients with liver cirrhosis after splenectomy or partial splenic embolization. Forty-nine hepatitis C patients with liver cirrhosis who were unable to use antiviral therapy because of hypersplenism were recruited for study and treated with splenectomy or partial splenic embolization. Three months later, a regimen of antiviral combination therapy was initiated with peg-IFNa-2a (once-weekly subcutaneous injection: 135 µg or 180 µg) and RBV (daily oral: 800 to 1200 mg), and was maintained for 48 weeks. The patients were followed up at treatment weeks 1, 2, 4, 6, 8, and 12. Thereafter, follow-up was conducted every four weeks. The patients were observed until 24 weeks after treatment discontinuation. Follow-up testing included liver function, blood chemistry, renal function, and HCV RNA level. Any adverse reactions were recorded. Liver cirrhosis patients complicated by hypersplenism can be treated effectively with peg-IFNa-2a/RBV combination antiviral therapy after splenectomy or partial splenic embolization. The antiviral-induced sustained viral response rates was 65.00% in cirrhotic/hypersplenic hepatitis C patients receiving splenectomy and 58.62% in those receiving partial splenic embolization. Hypersplenism patients with hepatitis C-related cirrhosis achieved a good antiviral therapeutic effect with peg-IFNa-2a/RBV combination therapy following splenectomy or partial splenic embolization. This sequence of treatment may help to decrease incidences of chronic hepatitis C-induced liver failure and liver cancer in these patients.

Synthesis and characterization of a multi-arm poly(acrylic acid) star polymer for application in sustained delivery of cisplatin and a nitric oxide prodrug.

Functionalized polymeric nanocarriers have been recognized as drug delivery platforms for delivering therapeutic concentrations of chemotherapies. Of this category, star-shaped multiarm polymers are emerging candidates for targeted delivery of anti-cancer drugs, due to their compact structure, narrow size distribution, large surface area and high water solubility. In this study, we synthesized a multi-arm poly(acrylic acid) star polymer via MADIX/RAFT polymerization and characterized it using NMR and size exclusion chromatography. The poly(acrylic acid) star polymer demonstrated excellent water solubility and extremely low viscosity, making it highly suited for targeted drug delivery. Subsequently, we selected a hydrophilic drug, cisplatin, and a hydrophobic nitric oxide-donating prodrug, O2-(2,4-dinitrophenyl) 1-[4-(2-hydroxy)ethyl]-3-methylpiperazin-1-yl]diazen-1-ium-1,2-diolate, as two model compounds to evaluate the feasibility of using poly(acrylic acid) star polymers for delivery of chemotherapeutics. After synthesizing and characterizing two poly(acrylic acid) star polymer-based nanoconjugates, poly(acrylic acid)-cisplatin (acid-Pt) and poly(acrylic acid)-nitric oxide prodrug (acid-NO), the in vitro drug release kinetics of both acid-Pt and acid-NO were determined at physiological conditions. In summary, we have designed and evaluated a polymeric nanocarrier for sustained-delivery of chemotherapies, either as a single treatment or a combination therapy regimen.

A sensitive near-infrared fluorescent probe for caspase-mediated apoptosis: Synthesis and application in cell imaging.

Near-infrared (NIR) absorbing dyes represent an intriguing avenue for extracting biological information from living subjects since they can be monitored with noninvasive optical imaging techniques. We designed and synthesized an imaging agent which contains a NIR fluorochrome (IR780) and peptidyl fluoromethyl ketone (FMK) for caspase-9 imaging of cells undergoing apoptosis. The IR780-FMK fluorescent probe had a Strokes shift of 79 nm and quantum yield 0.75. Prostate cancer DU145 cells undergoing apoptosis were successfully imaged using as little as 0.1 µM of IR780-FMK.

Pulmonary delivery of cisplatin-hyaluronan conjugates via endotracheal instillation for the treatment of lung cancer.

Cisplatin (CDDP) intravenous treatments suffer several dose-limiting toxicity issues. Hyaluronan (HA), a naturally occurring biopolymer in the interstitium, is primarily cleared by the lymphatic system. An alteration in input rate and administration route through pulmonary delivery of hyaluronan-cisplatin (HA-Pt) conjugate may increase local lung CDDP concentrations and decrease systemic toxicity. Sprague-Dawley rats were split into four groups: i.v. CDDP (3.5 mg/kg), i.v. HA-Pt conjugate (3.5 mg/kg equivalent CDDP), lung instillation CDDP and lung instillation HA-Pt conjugate. Total platinum level in the lungs of the HA-Pt lung instillation group was 5.7-fold and 1.2-fold higher than the CDDP intravenous group at 24 and 96 h, respectively. A 1.1-fold increase of Pt accumulation in lung draining nodes for the HA-Pt lung instillation group was achieved at 24h relative to the CDDP i.v. group. In the brain and kidneys, the CDDP i.v. group had higher tissue/plasma ratios compared to the HA-Pt lung instillation group. Augmented tissue distribution from CDDP i.v. could translate into enhanced tissue toxicity compared to the altered input rate and distribution of the intrapulmonary nanoformulation. In conclusion, a local pulmonary CDDP delivery system was developed with increased platinum concentration in the lungs and draining nodes compared to i.v. therapy.

Alkyne- and 1,6-elimination- succinimidyl carbonate - terminated heterobifunctional poly(ethylene glycol) for reversible "Click" PEGylation.

A new heterobifunctional (succinimidyl carbonate, SC)-activated poly(ethylene glycol) (PEG) with a reversible 1,6-elimination linker and a terminal alkyne for "click" chemistry was synthesized with high efficiency and low polydispersity. The α-alkyne-ω-hydroxyl PEG was first prepared using trimethylsilyl-2-propargyl alcohol as an initiator for ring-opening polymerization of ethylene oxide followed by mild deprotection with tetrabutylammonium fluoride. The hydroxy end was then modified with diglycolic anhydride to generate α-alkyne-ω-carboxylic acid PEG. The reversible 1, 6-elimination linker was introduced by conjugation of a hydroxymethyl phenol followed by activation with N,N'-disuccinimidyl carbonate to generate the heterobifunctional α-alkyne-ω-SC PEG. The terminal alkyne is available for "click" conjugation to azido ligands via 1,3-dipolar cycloaddition, and the succinimidyl carbonate will form a reversible conjugate to amines (e.g. in proteins) that can release the unaltered amine after base or enzyme catalyzed cleavage of the 1,6-linker.