Plasma Levels of Neopterin and Biopterin in the Umbilical Vessels and the Maternal Vein

Pteridines ◽  
2003 ◽  
Vol 14 (1) ◽  
pp. 1-4
Author(s):  
Naoko Iwanaga ◽  
Seiichi Yamamasu ◽  
Daisuke Tachibana ◽  
Junko Nishio ◽  
Yuichiro Nakai ◽  
...  
Keyword(s):  
Nitric Oxide ◽  
High Performance ◽  
Umbilical Artery ◽  
Umbilical Vein ◽  
Aromatic Amino Acids ◽  
Maternal Plasma ◽  
Chromatography Method ◽  
Fetal Plasma ◽  
Significant Difference ◽  
Liquid Chromatography Method

Abstract Tetrahydrobiopterin (BH4) is a highly bioactive pterin required for nitric oxide synthase and monooxygenases of aromatic amino acids, and is involved in the synthesis of nitric oxide, catecholamines and Serotonin. Although these functions imply that pterin metabolism plays critical roles in human development, the intrauterine metabolism is unclear. To elucidate the pterin metabolism in the human feto-placental unit, blood was obtained from the umbilical artery and vein, and the maternal vein, and plasma biopterin and neopterin concentrations were analyzed by the high-performance liquid chromatography method. To clarify the effect of labor, data was also compared between the transvaginal delivery (TV) and the caesarean delivery (CS). The levels of biopterin and the neopterin, and neopterin/biopterin ratio were higher in the fetal plasma than in the maternal plasma. Biopterin levels in the umbilical artery were higher than those in the umbilical vein. There were significant correlations in either biopterin or neopterin between the fetal plasma and the maternal plasma. There was no significant difference in the fetal pterin levels between TV and CS. The results suggest the stimulated BH4 synthesis in the fetoplacental unit, the independent homeostasis of the fetal pterin metabolism, and the possibility of dynamic movements of pterins among the fetus, the placenta and the mother.

scholarly journals Stability and Beyond-Use Date of a Compounded Thioguanine Suspension

2020 ◽  
pp. 875512252095243
Author(s):  
Sagar S. Gilda ◽  
William M. Kolling ◽  
Marcelo Nieto ◽  
Timothy McPherson
Keyword(s):  
United States ◽  
High Performance ◽  
Room Temperature ◽  
Physical Stability ◽  
The United States ◽  
Chromatography Method ◽  
Priority List ◽  
Significant Difference ◽  
Stability Data ◽  
Liquid Chromatography Method

Background: Thioguanine (TG) is available only in the form of 40 mg tablets in the United States, and the patient population in which TG is used comprises mostly children. Recognizing its importance as a therapeutic agent and limited stability data for its compounded preparation, the United States Pharmacopoeia has listed TG in its priority list of compounded preparations monographs. Objective: The goal of the present study was to generate stability data and establish a beyond-use date for compounded TG suspension. Methods: Suspensions were compounded using TG tablets and ORA-Plus and ORA-Sweet as vehicles. A robust high-performance liquid chromatography method was developed and validated. TG and guanine (G) in suspensions were quantified immediately after compounding and at regular intervals for 90 days. Physical stability of suspensions was evaluated by observation of organoleptic properties. Results: Results from the study indicate that average TG levels in suspensions remained above 90% of the starting concentration and G formation was less than 2.5% for 90 days. There was no statistically significant difference in the amount of TG degraded over 90 days between suspensions stored at room temperature and in refrigerated conditions. There was also no statistically significant difference in G concentration of suspensions between day 0 and day 90. Conclusion: TG suspensions are stable for 90 days when stored at room temperature or refrigerated conditions and the beyond-use date can be set to 90 days.

Increase in the concentration of immunoreactive endothelin in human pregnancy

1991 ◽  
Vol 129 (2) ◽  
pp. 301-307 ◽  
Author(s):  
I. Iwata ◽  
T. Takagi ◽  
K. Yamaji ◽  
O. Tanizawa
Keyword(s):  
Detection Limit ◽  
Amniotic Fluid ◽  
Vaginal Delivery ◽  
Umbilical Artery ◽  
Umbilical Vein ◽  
Plasma Concentrations ◽  
Late Pregnancy ◽  
Maternal Plasma ◽  
Fetal Plasma ◽  
The Mean

ABSTRACT Maternal plasma concentrations of immunoreactive endothelin (ir-ET) during pregnancy, labour and after birth were measured by radioimmunoassay. Concentrations of ir-ET in the umbilical artery, umbilical vein, amniotic fluid and neonatal urine were also examined. The mean (± s.e.m.) plasma ir-ET concentration in early pregnancy (4–7 weeks) was 13·7±0·5 pmol/l, which was significantly higher than that in non-pregnant women (5·9±0·3 pmol/l). During pregnancy, plasma ir-ET concentrations gradually decreased to a minimum of 11·5±0·4 pmol/l in weeks 20–23, and then increased again towards term (12·5±0·4 pmol/l after 36 weeks of pregnancy). In women undergoing vaginal delivery, the mean plasma ir-ET concentration (17·1±0·7 pmol/l) increased significantly, compared with that in late pregnancy. After delivery, the plasma ir-ET concentration decreased abruptly to 4·0±0·2 pmol/l on the first day. Plasma ir-ET concentrations in umbilical vessels were significantly higher than those in maternal plasma. In addition, concentrations in the umbilical artery were significantly higher than those in the umbilical vein in cases of vaginal delivery. Concentrations of ir-ET in amniotic fluid were much higher than those in maternal or fetal plasma. ir-ET concentrations in neonatal urine on day 1 after birth were below the detection limit (< 0·1 pmol/l) by radioimmunoassay in 70% of the cases examined but on day 5 after birth ir-ET was present at measurable concentrations in all cases. It is suggested that endothelin may act as a circulating hormone during pregnancy and labour in both maternal and fetal circulations. Journal of Endocrinology (1991) 129, 301–307

scholarly journals HPLC Quantification of Cytotoxic Compounds fromAspergillus niger

2017 ◽  
Vol 2017 ◽  
pp. 1-7
Author(s):  
Paula Karina S. Uchoa ◽  
Leandro Bezerra de Lima ◽  
Antonia T. A. Pimenta ◽  
Maria da Conceição F. de Oliveira ◽  
Jair Mafezoli ◽  
...  
Keyword(s):  
High Performance Liquid Chromatography ◽  
Liquid Chromatography ◽  
Standard Deviation ◽  
High Performance ◽  
Chromatography Method ◽  
Relative Standard ◽  
Validation Parameters ◽  
Cytotoxic Compounds ◽  
Liquid Chromatography Method ◽  
Marine Strain

A high-performance liquid chromatography method was developed and validated for the quantification of the cytotoxic compounds produced by a marine strain ofAspergillus niger. The fungus was grown in malt peptone dextrose (MPD), potato dextrose yeast (PDY), and mannitol peptone yeast (MnPY) media during 7, 14, 21, and 28 days, and the natural products were identified by standard compounds. The validation parameters obtained were selectivity, linearity (coefficient of correlation > 0.99), precision (relative standard deviation below 5%), and accuracy (recovery > 96).

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