Leucoxenols A and B,two new phenolics from Bornean medicinal plant Syzygium leucoxylon

The medicinal plant, Syzygium leucoxylon or commonly known as Obah found in North Borneo was considered as traditional medicine by local committee. Two new phenolics, leucoxenols A (1) and B (2) were isolated and identified as major secondary metabolites from the leaves of S. leucoxylon. Their chemical structures were elucidated based on spectroscopic data such as NMR and HRESIMS. Furthermore, these compounds were active against selected strains of fungi.     

Conversion from twice- to once-daily tacrolimus in pediatric kidney recipients: a pharmacokinetic and bioequivalence study

Background

The objectives of this study were to investigate pharmacokinetic and pharmacogenetic parameters during the conversion on a 1:1 (mg:mg) basis from a twice-daily (Prograf) to once-daily (Advagraf) tacrolimus formulation in pediatric kidney transplant recipients.

Methods

Twenty-four-hour pharmacokinetic profiles were analyzed before and after conversion in 19 stable renal transplant recipients (age 7–19 years). Tacrolimus pharmacokinetic parameters [area under the concentration-time curve (AUC_0–24), minimum whole-blood concentration (C_min), maximum whole-blood concentration (C_max), and time to achieve maximum whole-blood concentration (t_max)] were compared between Tac formulations and between CYP3A5 and MDR1 genotypes after dose normalization.

Results

Both AUC_0–24 and C_min decreased after conversion (223.3 to 197.5 ng.h/ml and 6.5 to 5.6 ng/ml; p?=?0.03 and 0.01, respectively). However, the ratio of the least square means (LSM) for AUC_0–24 was 90.8 %, with 90 % CI limits of 85.3 to 96.7 %, falling within bioequivalence limits. The CYP3A5 genotype influences the dose-normalized C_min with the twice-daily formulation only.

Conclusions

Both tacrolimus formulations are bioequivalent in pediatric renal recipients. However, we observed a decrease in AUC_0–24 and C_min after the conversion, requiring close pharmacokinetic monitoring during the conversion period.     

Molecular Absorbent Recirculating System therapy (MARS®) in pediatric acute liver failure: a single center experience

Background

Supportive care as a bridge to transplant or recovery remains challenging in children suffering from acute liver failure (ALF). We report our experience in children using the Molecular Absorbent Recirculating System (MARS®).

Methods

Retrospective data from children receiving therapy using MARS® from October 2009 to October 2012 were included in this single-center retrospective study. Patient characteristics, clinical presentation and complications of ALF, clinical and biological data before and after each MARS® session, technical modalities and adverse events were recorded.

Results

A total of six children underwent 17 MARS® sessions during the study period. Two adolescents were treated with the adult filter MARSFLUX® and four infants were treated with the MiniMARS® filter. The mean PEdiatric Logistic Dysfunction (PELOD) score at admission was 19 (range 11–33). All patients were mechanically ventilated, and four had acute kidney injury. The neurological course improved in one case, judged as stable in two cases and worsened in one case; data were unavailable in two cases. Mean serum ammonia levels decreased significantly following treatment with MARS® from an initial 89?±?29 to 58?±?35 mcmol/L (p?=?0.02). No other significant biological improvement was observed. Hemodynamic status improved/remained unchanged in the adolescent group, but in the infants four of the seven sessions were poorly tolerated and two sessions were aborted. Three patients died, two were successfully transplanted and one recovered without transplantation.

Conclusion

In our experience, treatment with MARS® is associated with encouraging results in adolescents, but it needs modification for very sick infants to improve tolerance.     

Sensitive quantification of mitochondrial mutation using new Taqman probes

The A3243G mitochondrial mutation is the major cause of mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes (MELAS). The severity of the disease is correlated with the heteroplasmy level of the mutation. Here we describe for the first time the validation of a real-time polymerase chain reaction (PCR) assay with Taqman locked nucleic acid (LNA) fluorescent (FAM for mutant, HEX for wild type) probes for quantification of heteroplasmy levels in a total of 18 family members from 5 Vietnamese MELAS patients carrying A3243G. Almost no background of FAM signals was detected in normal samples, indicating that the probes were allele-specific. Standard curves indicate sensitive detection at 0.1% mutants and high reliability with R² > 0.985. The correlation line between measured % mutant and expected % mutant was highly reliable, with a slope of 0.993 and R² of 0.998. All positive A3243G mutant samples pre-screened by PCR-restriction fragment length polymorphism (RFLP) were confirmed, and their heteroplasmy levels quantified to be from 3.68 to 80.85%. The heteroplasmy levels in patients were higher than in their family members and generally correlated well with the severity of their clinical symptoms. Overall, this work is the first demonstration of the application of LNA probes for sensitive and highly reliable quantification of heteroplasmy levels in human mitochondria.     

Enhanced power conversion efficiency of an n-Si/PEDOT:PSS hybrid solar cell using nanostructured silicon and gold nanoparticles

Herein, the effect of nanostructured silicon and gold nanoparticles (AuNPs) on the power conversion efficiency (PCE) of an n-type silicon/poly(3,4-ethylene dioxythiophene):poly(styrene sulfonate) (n-Si/PEDOT:PSS) hybrid solar cell was investigated. The Si surface modified with different nanostructures including Si nanopyramids (SiNPs), Si nanoholes (SiNHs) and Si nanowires (SiNWs) was utilized to improve light trapping and photo-carrier collection. The highest power conversion efficiency (PCE) of 8.15% was obtained with the hybrid solar cell employing SiNWs, which is about 8%, 20% and 40% higher compared to the devices using SiNHs, SiNPs and planar Si, respectively. The enhancement is attributed to the low reflectance of the SiNW structures and large PEDOT:PSS/Si interfacial area. In addition, the influence of AuNPs on the hybrid solar cell''s performance was examined. The PCE of the SiNW/PEDOT:PSS hybrid solar cell with 0.5 wt% AuNP is 8.89%, which is ca. 9% higher than that of the device without AuNPs (8.15%). This is attributed to the increase in the electrical conductivity and localized surface plasmon resonance of the AuNP-incorporated PEDOT:PSS coating layer.

n-Si/PEDOT:PSS hybrid solar cells using nanostructured silicon and AuNPs were prepared and investigated.