The effects of albumin bound fatty acids on the platelet inhibitory function of human endothelial cells

Abstract. This study was carried out to evaluate the effects of albumin-bound fatty acids on the anti-platelet effects of endothelial cells. Primary cultures of human endothelial cells (ECM), grown in confluent monolayers, were incubated with plasma or growth medium enriched with albumin-bound fatty acids (FA) for 2–20 h. The effects of ECM on ADP-induced platelet aggregation (PA) and collagen-induced PA and prostaglandin synthesis in platelet-rich plasma were tested.
ECM released an inhibitor of platelet reactions which resembled the activity of PGI₂ (prostacyclin). The inhibitory activity was increased by preincubation of ECM with arachidonic acid (AA). A moderate decrease of the activity was obtained by incubation with longchain saturated, monoenoic and dienoic unsaturated fatty acids. A pronounced decrease of the inhibitor was obtained by incubation with di-homo-γ-linolenic acid (DHLA).
Paired combinations of AA with the other fatty acids in the incubation medium partially restored the inhibitor activity obtained by the separate FA.
The stimulation of the inhibitor by AA was dose dependent and high concentrations of AA reduced this activity.
The present study indicates that the quantity and quality of the plasma free fatty acids can affect the endothelial cells' ability to act as a non-thrombogenic surface.     

Unconjugated serum bile acids as a marker of small intestinal bacterial overgrowth

Non-invasive methods to detect small intestinal bacterial overgrowth often lack specificity in patients who have undergone an ileal resection or have an accelerated intestinal transit. Since elevated serum unconjugated bile acid levels have been found in patients with clinical signs of bacterial overgrowth, we studied the clinical value of unconjugated serum bile acids as a marker of small intestinal bacterial overgrowth. Patients with culture-proven bacterial overgrowth had significantly elevated fasting unconjugated serum bile acid levels (median and range: 4.5; 1.4-21.5 mumol l-1) as compared to healthy subjects (0.9; 0.3-1.7 mumol l-1, P less than 0.005), to persons with an accelerated intestinal transit (1.0; 0.3-1.9 mumol l-1, P less than 0.005) and to persons who have undergone an ileal resection (2.1; 0.7-3.6 mumol l-1, P less than 0.005). The same was true 30 and 60 min after ingestion of a Lundh meal. Serum unconjugated bile acid levels above 4 mumol l-1 were found in eight of 10 patients with culture-proven small intestinal bacterial overgrowth whereas serum levels above 4 mumol l-1 were found in none of the patients from the three control groups. These results suggest that determination of unconjugated serum bile acids is of clinical value in the evaluation of patients suspected of small intestine bacterial overgrowth.     

Characterization of plasma acylcarnitines in patients under valproate monotherapy using ESI-MS/MS

Objectives: The effect of administration of the antiepileptic drug valproate (VPA), on the composition of the plasma acylcarnitine profile (including free carnitine) was investigated.

Design and methods: Plasma samples were obtained from 18 individuals (13♂:5♀; 15–65y) on long-term treatment with VPA (resulting in plasma levels of 14.6–135.0 mg/L; therapeutic conc.: 40–100 mg/L). Acylcarnitines (AC) in plasma were quantified by electrospray tandem mass spectrometry (ESI-MS/MS).

Results: VPA was found to increase the levels (mean ± SD, μM) of 3-hydroxy-isovalerylcarnitine (0.10 ± 0.04; controls: 0.02–0.06), C14:2 acylcarnitine (0.11 ± 0.05; controls: 0.02–0.08), propylglutarylcarnitine (0.06 ± 0.05; controls: 0.00–0.04), and C18-0H-acylcarnitine (0.09 ± 0.05; controls: 0.00−0.04). The free carnitine (C) (42.2 ± 9.0; controls: 22.3–54.9) and the total carnitine (52.3 ± 10.1; controls: 26.5–73.6) were not significantly altered by VPA. Other AC (C2-C18, monounsaturated and hydroxylated) were all within the control range and especially no increase of C8 (valproyl) carnitine was observed. A positive correlation was found between the ratios [AC] / [C] (p < 0.05) or [long-chain AC (C10-C18)] / [C] (p < 0.09) with the plasma VPA concentration.

Conclusions: The unequivocal increase in 3-hydroxy-isovalerylcarnitine is consistent with the increase of 3-hydroxy-isovaleric acid observed in urine of VPA treated patients. This finding suggests an interaction mechanism of VPA with specific enzymes, namely involved in leucine metabolism. Adult patients under VPA monotherapy do not suffer from carnitine deficiency; the effect of the accumulating acylcarnitines is ill-defined.     

Incorporation of 5-fluorouracil into rat liver tumor and normal tissues and the liver nucleotide profile after administration by the hepatic artery during portal venous branch ligation

A therapeutic dose of labelled 5-fluorouracil (5-FU) was infused via the hepatic artery during 30 min with or without ligation of the left portal venous branch in Wistar rats with a secondary liver cancer in the left lateral lobe. After another 60 min, the incorporation of 5-FU into the acid soluble fraction (ASF), ribonucleic acid (RNA) and deoxyribonucleic acid (DNA), was determined in tumor, ligated and unligated liver lobes, small intestine, kidney, and bone marrow. The liver nucleotide profile was examined with isotachophoresis. Portal venous branch ligation (PVBL) caused the following changes, compared with the unligated control group: in the tumor, the incorporation of 5-FU into RNA and DNA decreased and the ratio RNA/acid-soluble fraction labelling decreased. The incorporation increased in intestinal and bone marrow RNA. It was unchanged in liver and kidney. The ratio of tumor to peripheral normal-tissue (small intestine, bone marrow, and kidney) labelling of RNA and DNA decreased. Liver nucleotides (F) UTP, (F)UDP-glucuronic acid, (F)UDP-N-acetylhexosamine, and NAD were lower in the ligated than in the unligated liver lobe. ATP and energy charge did not decrease significantly. In conclusion, PVBL in conjunction with hepatic arterial administration of 5-FU increased systemic drug exposure and possibly decreased hepatic tumor anabolism. It has not been examined how this interferes with the therapeutic effect.     

平衡型氨基酸透析液血液透析治疗临床应用观察

目的设计平衡型氨基酸透析液，应用于维持性血液透析患者常规血液透析治疗，观察临床应用效果。方法选用解放军总医院第一附属医院长期维持性血液透析患者29例，透析2～3次／w，实验采用自身交叉对照设计，使用碳酸氢盐透析液1月后，再应用平衡型氨基酸透析液1月，分别观察血液生化指标、血浆蛋白、肾功能以及炎症指标的变化。结果血浆氨基酸谱显示绝大部分游离氨基酸及总游离氨基酸含量均恢复到与健康人相仿的水平；平衡型氨基酸透析液治疗后尿素氮、肌酐、尿酸等。肾功能指标有不同程度的升高，但电解质及钙、磷没有明显的变化；血浆总蛋白（TP）、白蛋白（ALB）、前白蛋白（PreA）、转铁蛋白（Trf）等较前无明显变化，但β2微球蛋白（β2-MG）和超敏C反应蛋白（SCRP）则较应用前有明显的降低（P〈0．01和P〈0．05）。结论平衡型氨基酸透析液能减少维持性血液透析患者的氨基酸丢失，部分改善其体内的氨基酸代谢紊乱，同时有可能减轻体内的微炎症反应。     

A biochemical perspective on the use of tandem mass spectrometry for newborn screening and clinical testing

The first newborn screen was a clinical test to detect a disorder of the biochemistry of the amino acid, phenylalanine. This disorder, known as phenylketonuria, produces profound mental retardation if not detected and treated early in life. Early screening programs relied on inexpensive population screening techniques that have all but been replaced by more accurate analytical methods such as tandem mass spectrometry (MS/MS). MS/MS enables a multianalyte approach for detecting biochemical disorders such that a metabolic profile is obtained rather than a single analyte measurement. The metabolic profile has clearly shown improvements in the detection of diseases such as phenylketonuria and several new disorders arising from errors in fatty acid oxidation and organic acid metabolism. MS/MS is a powerful tool for accessing the metabolic status of a newborn and can detect both inborn metabolic errors as well as examine the effect of acquired diseases or pharmacologic intervention on intermediary metabolism.     

Are fatty acids and fatty acid binding proteins novel biomarkers for cryoablation efficiency?

PurposeCryoablation is a recommended, modern and well-tolerated method of treating atrial fibrillation (AF). The study evaluates plasma biomarkers related to AF and the effectiveness of its treatment – cryoablation. Heart- and adipocyte-type fatty acid binding proteins (H-FABP and A-FABP, respectively) as well as fatty acids (FAs) were assessed in patients that underwent cryoballoon ablation (CBA) for AF.Patients and methodsConcentrations of plasma FABPs and FAs were measured in 33 AF patients on admission and 24 ?h after CBA (enzyme-linked immunoassay and gas liquid chromatography, respectively). The control group consisted of 20 volunteers.ResultsWe showed that plasma H-FABP and A-FABP concentrations were significantly higher in the patients with AF than in the control group (1135 ?pg/mL vs 836 ?pg/mL, and 34.29 ?ng/mL vs 15.14 ?ng/mL, respectively; p ?< ?0.05). After CBA, H-FABP plasma concentration increased even further (1574 ?pg/mL vs 1135 ?pg/mL; p ?< ?0.05) and FAs levels decreased concomitantly. AF recurred in 8 patients (24.25%) after 3 months and in 13 patients (39.4%) after 6 months. Initially higher concentration of oleic acid (680.24 ?± ?189.768 vs 567.04 ?± ?70.002; p ?< ?0.05) correlated substantially with lower AF relapse rate in 6 months follow-up.ConclusionsThe patients with AF showed increased concentration of H-FABP, whereas CBA triggered further elevation of H-FABP with a simultaneous decline in the total plasma FAs concentration. H-FABP and A-FABP could not be confirmed as new biomarkers of cryoablation efficiency, but this requires further investigation due to the limitations of the study.     

Insulin and HOMA in Spanish prepubertal children: relationship with lipid profile

OBJECTIVE: The effects of insulin or insulin resistance on the lipid profile seem to change with age. The aim of this study was to analyze insulin levels and an insulin resistance index and to investigate the relationship between these and the lipid profile in a population-based sample of Spanish prepubertal children. METHODS: 1048 (524 boys and 524 girls) randomly selected prepubertal children were studied. Children were 6 to 8 years old with a mean age of 6.7. Plasma lipid, FFA and insulin levels were measured. The homeostatic model assessment (HOMA) was calculated as an indicator of insulin resistance. RESULTS: When analyzing percentile values of insulin, HOMA and FFA by sex, we observed that girls had significantly higher insulin concentrations than boys (except at the 10th percentile) and significantly higher FFA (except at the 90th percentile) with no significant differences between sexes for HOMA. Multivariate regression analyses showed that insulin was positively associated with glucose, triglycerides and apoB in boys but not in girls, and negatively associated with FFA in both genders. CONCLUSIONS: We report here data about the distribution of insulin in the Spanish prepubertal population. The higher levels of insulin in prepubertal girls could indicate that girls start to be more insulin resistant than boys at this age, although other manifestations of insulin resistance are not yet detectable.     

毛细管电泳-激光诱导荧光法分离四种神经递质类氨基酸的条件优化

目的探讨毛细管电泳分离神经递质类氨基酸的影响因素。方法采用毛细管电泳法分离4种神经递质类氨基酸的荧光素异硫氰酸酯(FITC-AAs)衍生物,分析电泳缓冲液、表面活性剂以及衍生条件对分离的影响。结果电泳缓冲液的组成、浓度、pH值、表面活性剂以及衍生条件对4种FITC-AA衍生物分离有很大影响,在以75 mm ol/L,pH 9.42硼酸盐含100 mm ol/LSDS为电泳缓冲液,50 mmol/LpH 9.8硼酸盐为衍生缓冲液,4种FITC-AA衍生物20 min内得到很好分离。结论通过条件优化,毛细管电泳-激光诱导荧光技术分离神经递质类氨基酸的分离效果能得到很大提高。