Biomedical subjects

S Mou

Publications and source records attributed to S Mou.

24 records · Page 2Linked to original sources

PubMed1997

[Study on ion chromatography (IC) for the low-molecular weight amines].

In this paper the retention behaviors of low-molecular weight amines (methylamine, dimethylamine, trimethylamine, ethylamine, propylamine sec-butylamine, n-butylamine, ethanolamine, diethanolamine, triethanolamine) on Ionpac CS12 column were for the first time studied with modern ion chromatograph. The column is usually used for routine analysis of inorganic cations and it strongly retains these organic amines. So they are difficult to be eluted by dilute aqueous HCl alone. The addition of acetonitrile (ACN) as a modifier can improve the peak shape and resolution. Influences of concentrations (ACN & HCl) on separation and detection were investigated separately and the chromatographic conditions were optimized. Aqueous solution of 20 mmol/L HCl containing 1% or 5% ACN (5% for higher molecular weight amines) was used as the eluant with a flow rate of 1.0 mL/min to optimize the column efficiency. In addition to methylamine, ethanolamine and diethanolamine, all other amines can well be separated from each other. According to the structure they may be divided into three classes: (a) methylamine, dimethylamine and trimethylamine; (b) diethanolamine and triethanolamine; (c) ethylamine, propylamine, sec-butylamine and n-butylamine. The three classes of mixtures were separately injected into the IC system and resolutions being obtained by the developed method were: (a) 1.25 and 1.52; (b) 1.20; (c) 2.45, 2.05 and 2.10 respectively. The new method is characterized by rapidity, convenience, sensitivity and simultaneous determination of some inorganic cations. It was separately used for determination of diethanolamine, triethanolamine, NH4+ in explosive samples and of Na+, K+, MgZ+, Ca2+ in water supply with satisfactory results. The retention mechanism of amines on CS12 column and effect of organic modifier were also preliminarily explored.

Biogenic Amines↗

PubMed1997

[Determination of organic acids and inorganic anions by gradient ion chromatography].

The chromatographic conditions for separation and detection of organic acids and inorganic anions by gradient ion chromatography with suppressed conductivity detection were studied. The optimized gradient programs were established. Ion chromatography were performed with a DX-100 chromatograph (DIONEX). The separation column is IonPac-AS11. Compared with NaHCO3/Na2CO3 and Na2B4O7, NaOH was the optimal eluent. The effect of organic modifier was also studied. Among methanol, 2-propanol and acetonitrile, methanol can make ion pairs such as malate and succinate, malonate and tartrate gaining baseline resolution. By using ion exchange separation, Cl-, NO3-, malate, succinate, malonate, tartrate, SO4(2-), oxalate were eluted between 5 mmol/L NaOH-16% CH3OH and 10 mmol/L NaOH-16% CH3OH in 25 min. A mobile phase composed of 30 mmol/L NaOH, 50% CH3OH and D.I. water was chosen to elute two groups of organic acids and inorganic anions: (1) quinate, formate, Cl-, malate, malonate, oxalate, citrate, isocitrate, aconitate; (2) lactate, Cl-, SO4(2-), tartrate, PO4(3-), citrate, isocitrate, aconitate. The detection limits (S/N = 3) were 0.1625 (quinate), 0.0691 (formate), 0.0115 (Cl-), 0.0886 (malate), 0.0591 (malonate), 0.0263 (oxalate), 0.1147 (citrate), 0.2017 (isocitrate), 0.3656 (cis-aconitate), 0.1045 (trans-aconitate), 0.1950 (lactate), 0.0729 (tartrate), 0.0224 (SO4(2-)) and 0.0692 (PO4(3-)) mg/L. The relative standard deviations were lower than 11.9% (n = 7) and the correlation coefficients ranged from 0.9212 for Cl- to 0.9999 for formate. The method was applied to determine the organic acids and inorganic anions of beverages and citric acids fermenting-medium. The results were satisfactory.

Anions↗

PubMed1996

JAK2 is associated with the c-kit proto-oncogene product and is phosphorylated in response to stem cell factor.

Stem cell factor (SCF) is a hematopoietic growth factor that interacts with the receptor tyrosine kinase, c-kit. We have found that SCF-stimulates rapid and transient tyrosine phosphorylation of JAK2 in human and murine cell lines, as well as in normal human progenitor cells. JAK2 and c-kit were associated in unstimulated cells with further recruitment of JAK2 to the c-kit receptor complex after SCF stimulation. Treatment of cells with JAK2 antisense oligonucleotides resulted in a 46% decrease in SCF-induced proliferation. These data demonstrate that SCF induces tyrosine phosphorylation of JAK2 and suggest that JAK2 is a component of the SCF signal transduction pathway.

Animals↗

PubMed1996

JAK2 is constitutively associated with c-Kit and is phosphorylated in response to stem cell factor.

Stem cell factor (SCF) interacts with the receptor tyrosine kinase c-Kit and has potent effects on hematopoiesis. We have examined the role of JAK2 in the SCF signal transduction pathway. JAK2 and c-Kit were constitutively associated, and treatment with SCF resulted in rapid and transient tyrosine phosphorylation of JAK2. Incubation of cells with JAK2 antisense oligonucleotides resulted in significant decreases in SCF-induced proliferation. These data suggest that JAK2 plays a role in SCF-induced proliferation.

Animals↗

PubMed1991

Effects of albumin on ionized calcium in vitro.

Human serum albumin is used to treat hypoproteinemia in neonates or used as a volume expander. We tested the hypothesis that the addition of human serum albumin to neonatal serum decreases the serum ionized calcium (iCa) concentration. Concentrated human serum albumin was added to 12 placental and cord serum samples to reach seven incremental concentrations from 0 to 20.0 g/L. Serum iCa concentration decreased significantly with the addition of serum albumin. From multiple regression analysis, the effect of albumin addition on serum iCa concentration had more marked effects at high baseline albumin or low baseline Ca concentrations. From this in vitro study, we speculate that fast infusion of albumin in human neonates has the potential for acutely lowering serum iCa concentration.

Blood Proteins↗

PubMedDate not supplied

Effects of methadone use during pregnancy on human placental opioid receptors.

Human placenta was used to investigate the effects of chronic methadone use during pregnancy on villus tissue opioid receptors. Patients included in this investigation received 35-60 mg methadone per day. Methadone-exposed placenta villus tissue had no detectable opioid receptor binding sites measured by tritiated opioid agonists. In vitro release of acetylcholine and hCG from trophoblast tissue of methadone-exposed placentas was not modulated by opioids. Absence of opioid receptor binding sites and their two mediated responses in trophoblast tissue of placentas obtained from patients with documented chronic methadone use during pregnancy indicate that the receptors were down regulated or desensitized.

Acetylcholine↗