Total platinum concentration and platinum oxidation states in body fluids, tissue, and explants from women exposed to silicone and saline breast implants by IC-ICPMS

Ion chromatography-inductively coupled plasma-mass spectrometry was used to determine the total platinum concentration and platinum oxidation states in samples from women exposed to silicone and saline breast implants. Samples included the following: whole blood, urine, hair, nails, sweat, brain tissue, breast milk, and explants. Mean Pt concentration in samples from women exposed to silicone breast implants were as follows: whole blood, 568.1 +/- 74.77 pmol/L (n = 9); urine, 1.77 +/- 0.847 mug/g of creatinine (n = 10); hair, 2.13 +/- 2.984 ng/g (n = 9); nails, 0.88 +/- 0.335 ng/g (n = 9); sweat, 1.90 +/- 1.691 ng/g (n = 9); breast milk, 1.09 +/- 0.316 mug/L (n = 6). Pt in explanted silicone breast implant gel (n = 9) occurred mainly in the +2, +4, and +6 oxidation states. Pt in whole blood (n = 7) and breast milk samples (n = 6) from women exposed to silicone breast implants occurred mainly in the +2 and +4 oxidation states. Saline breast implant fluid (n = 2) did not contain detectable levels of Pt. This is the most comprehensive report, to date, to show that women exposed to silicone breast implants have Pt levels that exceed that of the general population, and the first report, to date, to document the various Pt oxidation states present in samples from women exposed to silicone breast implants.     

Determination of 25-hydroxyvitamin D in human plasma using high-performance liquid chromatography--tandem mass spectrometry

We report here the development of a precise and sensitive method to determine 25-hydroxyvitamin D (25-OH-D(2)/ -D(3)) in human plasma using high-performance liquid chromatography-tandem mass-mass spectrometry with atmospheric pressure chemical ionization (LC-APCI-MS/MS). The method involves the use of deuterated 25-OH-D(3) as an internal standard compound for 25-OH-D(2)/-D(3), which was synthesized in our laboratory, and the selection of a precursor and product ion with a MS/MS multiple reaction monitoring method. The average intraassay and interassay variation values (relative standard deviation) were 5.7 and 2.5%, respectively, for 25-OH-D(3) and 4.5 and 5.1%, respectively, for 25-OH-D(2). The average spiked recoveries from authentic compounds added to normal human plasma samples for 25-OH-D(3) and 25-OH-D(2) were 103.8 and 98.8%, respectively. Mean plasma concentrations of 25-OH-D(3) and 25-OH-D(2) in healthy subjects were 20.5 and 0.4 ng/mL, respectively. We conclude that this novel LC-APCI-MS/MS method would be useful for the evaluation of the vitamin D status in postmenopausal women and elderly subjects and provide useful information in the diagnosis of vitamin D insufficiency/deficiency, as well as for the treatment and prevention of osteoporosis with vitamin D.     

Prognostic significance of 25‐hydroxivitamin D entirely explained by a higher comorbidity burden: Experience from a South‐Eastern European Dialysis Cohort

Vitamin D deficiency is still a common problem particularly in the elderly and in individuals with various degrees of renal impairment. The present study aimed to evaluate the association between plasma concentrations of 25(OH)D and death in a large cohort of prevalent patients on hemodialysis (HD) from south‐east Romania, a typical Balkan region. This is an observational prospective study that included a total of 570 patients on maintenance HD. Study patients were classified into three groups by baseline 25(OH)D levels: (1) sufficient 25(OH)D—i.e., >30 ng/mL; (2) insufficient 25(OH)D—i.e., between 10 and 29 ng/mL; and (3) deficient 25(OH)D—i.e., <10 ng/mL. During the follow‐up period of 14 months, 68 patients (11.9%) died, the Kaplan–Meier analysis showing significant differences in all‐cause mortality for chronic kidney disease patients in different 25(OH)D groups (P = 0.002). Unadjusted Cox regression analysis also showed significant differences in survival. The multivariate Cox regression model showed no significant differences in survival according to vitamin D levels. Hazard ratio for death in the “<10 ng/mL” group was 1.619 (P = 0.190) and in the “10–30 ng/mL” group was 0.837 (P = 0.609). In our dialysis population with a high comorbidity burden, low 25(OH)D concentration was not associated with mortality in the adjusted Cox model, suggesting that vitamin D deficiency could represent only a non‐specific marker for a poor health status, with less impact on mortality.     

Methods for detecting silicones in biological matrixes.

Methods for analyzing for silicon and silicone in biological matrixes were developed. A silicone-specific technique involved microwave digestion of samples in acid solution to rapidly break down the biological matrix while hydrolyzing silicones to monomeric species. The resulting monomeric silanol species were then capped with trimethylsilyl groups, extracted into hexamethyldisiloxane, and analyzed by gas chromatography. In serum, positive identification of silicone species with detection limits below 0.5 microgram of Si/mL are possible with this technique. The technique is compared with a silicone-specific technique, 29Si NMR, and a non-silicone-specific technique, ICP-AES. 29Si NMR was far less sensitive, with a detection limit of only 64 micrograms of Si/mL in serum when analyzing for one compound with a single sharp resonance. Inductively coupled plasma-atomic emission spectroscopy (ICP-AES) has potentially lower detection limits, but the technique is not silicone-specific and suffers from species-dependent responses.     

Prevalence of 25(OH) vitamin D insufficiency and deficiency in chronic kidney disease stage 5 patients on hemodialysis

Little is known about the magnitude of vitamin D deficiency in patients with stage 5 chronic kidney disease (CKD-5) on hemodialysis (HD). In the present study, we examined the prevalence of vitamin D deficiency in patients with CKD-5 undergoing HD, evaluating the relationship between calcidiol levels with other parameters of mineral metabolism, nutrition/inflammation, functional capacity (FC), and sunlight exposure. Serum 25(OH) vitamin D levels were evaluated in 84 stable patients on chronic HD not receiving vitamin D supplements, with a mean age 58.9+/-16.6 years, during the month of September (end of winter in the southern hemisphere). 25(OH) vitamin D serum levels, intact PTH (iPTH), as well as serum albumin, calcium, phosphorus, and alkaline phosphatase were analyzed in fasting samples. Similarly, protein catabolic rate (PCR) and body mass index (BMI) were determined as nutritional parameters. Functional capacity according to the Karnofsky index, and sunlight exposure were also analyzed. In this study, we considered adequate vitamin D levels those above 30 ng/mL (U.S.A. National Kidney Foundation DOQI Guidelines), vitamin D insufficiency when levels were between 15 and 30 ng/mL, and vitamin D deficiency when levels were below 15 ng/mL. The mean 25(OH) D levels were significantly higher in men than in women (28.6 vs. 18.9 ng/mL; p=0.001). Vitamin D insufficiency was found in 53.5% of the patients (n=45) and vitamin D deficiency in 22.6% (n=19). In the univariate analysis, there were no correlations between 25(OH) D levels with age, iPTH, calcium, or phosphorus. There were positive correlations between serum 25(OH) D levels and degrees of sunlight exposure (R=0.55; p<0.0001), serum creatinine (r=0.38; p<0.001), serum albumin (r=0.22; p=0.04), and a negative correlation with BMI (r=-0.26; p=0.01). In the multiple regression analysis, only sunlight exposure (B=0.361), BMI (B=-0.23), and gender (B=-0.27) were significantly associated with 25(OH) D levels. Patients with FC 1 to FC 2 (n: 70%, 83.3%) had significantly higher 25(OH) D serum levels compared with FC 3 to FC 4 patients (n: 14%, 16.6%): 25.9 vs. 17.1 ng/mL (p=0.03). These results indicate that vitamin D insufficiency/deficiency is highly prevalent (76.1%) at the end of winter, in stage 5 CKD patients on HD, and lower values seem to be related to decreased sunlight exposure, female gender, increased BMI, and worse functional class.     

聚硅氧烷与丙烯酸酯弹性体的制备及性能

用含乙烯基的硅氧烷单体和八甲基环四硅氧烷与丙烯酸酯共聚,制备出不同硅含量的硅丙乳液,研究了有机硅含量对微乳液聚合过程和乳胶膜透明性、交联度、热性能和力学性能的影响。结果表明,随着硅含量的增加,综合性能均得到改善,当有机硅单体用量达20%时为最佳配比。     

Enhanced cell adhesion to silicone implant material through plasma surface modification

Silicone implant material is widely used in the field of plastic surgery. Despite its benefits the lack of biocompatibility this material still represents a major problem. Due to the surface characteristics of silicone, protein adsorption and cell adhesion on this polymeric material is rather low. The aim of this study was to create a stable collagen I surface coating on silicone implants via glow-discharge plasma treatment in order to enhance cell affinity and biocompatibility of the material. Non-plasma treated, collagen coated and conventional silicone samples (non-plasma treated, non-coated) served as controls. After plasma treatment the change of surface free energy was evaluated by drop-shape analysis. The quality of the collagen coating was analysed by electron microscopy and Time-Of-Flight Secondary Ion Mass Spectrometry. For biocompatibility tests mouse fibroblasts 3T3 were cultivated on the different silicone surfaces and stained with calcein-AM and propidium iodine to evaluate cell viability and adherence. Analysis of the different surfaces revealed a significant increase in surface free energy after plasma pre-treatment. As a consequence, collagen coating could only be achieved on the plasma activated silicone samples. The in vitro tests showed that the collagen coating led to a significant increase in cell adhesion and cell viability.     

t-PAIC单克隆抗体制备及磁微粒化学发光免疫检测

以组织型纤溶酶原激活剂-抑制剂复合物（t-PAIC）为免疫原制备和筛选了一对特异性单克隆抗体,并建立了一种检测人体血浆t-PAIC的磁微粒化学发光免疫检测方法。通过与参比方法比对,选定了反应速度更快的一步法作为反应模式,然后对t-PAIC检测方法的检测性能进行了评估。结果显示：该方法的空白限为0.43 ng/mL,检出限为0.91 ng/mL;线性范围为0.91～100ng/mL;重复性CV小于4%,精密度CV小于3%;样本回收率在100%～110%之间;常见干扰物对检测结果无明显影响。构建了t-PAIC检测方法的参考区间,健康成年男性参考范围为1.85～15.91 ng/mL,健康成年女性参考范围为1.90～9.43 ng/mL。t-PAIC检测方法反应快速,在血栓疾病诊断中有重要的应用价值。     

A histological and histomorphometrical evaluation of screw-type calciumphosphate (Ca-P) coated implants; an in vivo experiment in maxillary cancellous bone of goats

The bone response to different calcium phosphate (Ca-P) coated implants was evaluated in a goat animal model. Two types of plasma spray coatings were applied to a commercially pure titanium (cpTi) tapered, conical screw-design implant (BioComp^®); hydroxyapatite (HA-PS) and a dual coating, consisting of FA and HA (FA/HA-PS). In addition an amorphous RF magnetron sputter coating (Ca-P-a) and uncoated implants were investigated. Forty-eight implants were inserted in the maxilla of 12 adult female goats. After implantation periods of 3 and 6 months, the bone implant interface was evaluated histologically and histomorphometrically. After both implantation periods all plasma spray coated implants were maintained. On the other hand three Ca-P-a and two cpTi implants were lost. Histological examination revealed a better bone response to both plasma spray coated implants. Histomorphometrical evaluation confirmed this finding. At 3 and 6 months significantly higher percentages of bone contact (p<0.001, ANOVA) were measured for both plasma spray coated implants than for the cpTi and Ca-P-a implants, while no significant difference (p<0.05) existed between both implantation periods. Degradation of both plasma spray coatings was observed. Supported by the results, it is concluded that, although Ca-P coatings can improve the performance of dental implants, the presence of a Ca-P coating is not the only important factor for bone healing around implants placed in low density trabecular bone.     

Ultrasensitive determination of phencyclidine in body fluids by surface ionization organic mass spectrometry

Gas chromatography (GC)/surface ionization organic mass spectrometry (SIOMS) has been found to give much higher sensitivity for measurements of phencyclidine (PCP) than the conventional GC/electron impact (EI)-mass spectrometry (MS). Thus, we have established a detailed procedure for measurements of PCP in body fluids by both mass chromatography and selected-ion monitoring (SIM) of SIOMS using pethidine as an internal standard (IS). Good linearity was found in the range of 0.25-10 ng/mL of whole blood or urine, when measured by mass chromatography, and in the range of 0.025-1.0 ng/mL of whole blood by SIM. The recoveries of PCP and IS spiked to whole blood were 106 +/- 17% at 1 ng/mL and 113 +/- 11% at 5 ng/mL; that of IS was 97.8 +/- 10.4% at 5 ng/mL. The detection limits (signal-to-noise ratio = 3) were estimated to be 0.05 ng/mL of whole blood or urine by mass chromatography and 0.01 ng/mL of whole blood by SIM. The coefficients of intraday and interday variations were not greater than 10.3%. We could detect PCP from rat whole blood 2 h after subcutaneous injection of PCP (1 mg/kg) by mass chromatography. The mean PCP concentration in rat blood was 47.7 +/- 6.2 ng/mL (mean +/- SD, n = 4).     

Selected reaction monitoring LC-MS determination of idoxifene and its pyrrolidinone metabolite in human plasma using robotic high-throughput, sequential sample injection

The generation of large numbers of samples during early drug discovery has increased the demand for rapid and selective methods of analysis. Liquid chromatography-tandem mass spectrometry (LC-MS-MS), because of its sensitivity, selectivity, and robustness, has emerged as a powerful tool in the pharmaceutical industry for many analytical needs. This work presents a high-throughput selected reaction monitoring LC-MS bioanalytical method for the determination of idoxifene, a selective estrogen receptor modulator, and its pyrrolidinone metabolite in clinical human plasma samples. The described method uses short, small-bore columns, high flow rates, and elevated HPLC column temperatures to perform LC separations of idoxifene and its metabolite within 10 s/sample. Sequential injections were accomplished with a 215/889 multiple probe liquid handler (Gilson, Inc.), which aspirates eight samples simultaneously and performs its rinse cycle parallel to sample injection, resulting in minimum lag time between injections. This high-throughput method was applied to the determination of idoxifene and its metabolite in clinical human plasma samples. Sample preparation employed liquid/liquid extraction in the 96-well format. Method validation included determination of intra- and interassay accuracy and precision values, recovery studies, autosampler stability, and freeze-thaw stability. The LOQ obtained was 10 ng/mL for idoxifene and 30 ng/mL for the metabolite. Using idoxifene-d5 as an internal standard, idoxifene showed acceptable accuracy and precision values at QC level 1 (QC1, 15 ng/mL), level 2 (QC2, 100 ng/mL), and level 3 (QC3, 180 ng/mL) (85.0% accuracy +/- 12.0% precision, 95.1 +/- 4.9%, and 90.3 +/- 4.7%, respectively). The pyrrolidinone metabolite also showed acceptable accuracy and precision values (using no internal standard for quantitation) at QC1 (60 ng/mL), QC2 (100 ng/mL), and QC3 (180 ng/mL) (104.9 +/- 14.4%, 91.1 +/- 13.0%, and 90.8 +/- 12.2%, respectively). The validated method was applied to the analysis of 613 human clinical plasma samples. An average run time of 23 s/sample (approximately 37 min/ 96-well plate or over 3,700 sample/day) was achieved. The successful validation presented indicates that rapid methods of analysis can efficiently and reliably contribute to the fast sample turnaround required for high sample number generating processes.     

Multielemental determination of GEOTRACES key trace metals in seawater by ICPMS after preconcentration using an ethylenediaminetriacetic acid chelating resin

GEOTRACES is an international research project on marine biogeochemical cycles of trace elements and their isotopes. GEOTRACES key trace metals in seawater are Al (8-1000 ng/kg), Mn (4-300 ng/kg), Fe (1-100 ng/kg), Cu (30-300 ng/kg), Zn (3-600 ng/kg), and Cd (0.1-100 ng/kg), of which global oceanic distribution will be determined on a number of research cruises. This work introduces a novel method of solid-phase extraction to determine Al, Mn, Fe, Co, Ni, Cu, Zn, Cd, and Pb in seawater by adjusting the pH of the sample to 6 and carrying out a single preconcentration step. The trace metals were collected from approximately 120 mL of seawater using a column of a chelating resin containing the ethylenediaminetriacetic acid functional group and eluted with approximately 15 mL of 1 M HNO3. Mn and Fe in the eluate were measured by inductively coupled plasma mass spectrometry (ICPMS) using the dynamic reaction cell mode, and the other metals were measured using the standard mode. Using this procedure, the trace metals were collected quantitatively, while >99.9% of alkali and alkaline earth metals in seawater were removed. The procedural blank was <7% of the mean concentration in deep ocean waters, except 16% for Pb. The overall detection limit was <14% of the mean concentration in deep ocean waters. The RSD was <9%. Our values for the trace metals in the certified reference materials of seawater NASS-5 and nearshore seawater CASS-4 agreed with the certified values (except that there is no certified value for Al). This method was also successfully applied to the reference materials of open-ocean seawater produced by the SAFe program. Our Fe concentrations were 5.9 +/- 0.7 ng/kg for surface water (S1) and 50.4 +/- 2.9 ng/kg for deep water (D2), which are in agreement with the interlaboratory averages of 5.4 +/- 2.4 and 50.8 +/- 9.5 ng/L, respectively. The data for other metals were oceanographically consistent.     

Quantitation of endogenous analytes in biofluid without a true blank matrix

A method is presented that describes a reliable and practical procedure for quantitation of an analyte present at relatively high background levels in blank (untreated) biological matrixes. Using a "surrogate analyte" approach, an endogenous analyte was quantitated in a variety of biological matrixes containing both very low (<10 ng/mL) and high (>2000 ng/mL) background levels of the desired analyte. This quantitative "surrogate analyte" approach was applied during the development of an HPLC/MS method for alpha-ketoisocaproic acid (KIC), which was identified as a potential biomarker for branched chain amino acid transferase inhibitor activity. Using deuterium-labeled KIC (d(3)) as a surrogate analyte, not an internal standard, to generate the calibration curve, the concentration of KIC in biofluid could be back-calculated based on the regression equation and response factor of KIC to KIC-d(3). In particular, this approach made it possible to prepare standards in control biofluid such as plasma, which greatly facilitated the process of method development. For the validated method, a linear range of 10-5000 ng/mL for KIC-d(3) was observed. Intraday and interday experimental accuracy, calculated as percent error, were in the range of < or =10% for KIC-d(3). This method is simple, rapid, and reliable for the quantitation of KIC in plasma, brain homogenate, cerebrospinal fluid, and other biological samples from discovery and pharmacological studies.     

Development and validation of a liquid chromatography-tandem mass spectrometry assay for the quantification of docetaxel and paclitaxel in human plasma and oral fluid

A quantitative method for the simultaneous determination of docetaxel (Taxotere), paclitaxel (Taxol), 6alpha-hydroxypaclitaxel, and p-3'-hydroxypaclitaxel in human plasma and oral fluid is developed and validated. Oral fluid (this term is now preferred to saliva) was sampled with a Salivette collection device. The procedure used a simple liquid/liquid extraction with methyl tert-butyl ether followed by LC-ESI-MS/MS. Gradient elution was applied and provided increased robustness to ion suppression by the drug formulation vehicle (polysorbate 80 and Cremophor EL). Adduct ion formation with sodium and potassium was noticed and controlled by mobile-phase optimization. The protonated analytes generated in the positive ion mode were monitored through multiple reaction monitoring. Calibration was performed by internal standardization with cephalomannine, and regression curves were constructed ranging between 2 and 1000 ng/mL in plasma and 0.125 and 62.5 ng/mL in oral fluid, using a weighing factor of 1/x2. The regression curves were quadratic for paclitaxel and docetaxel and linear for the paclitaxel metabolites. Accuracy varied from 91.3 to 103.6%, and imprecision did not exceed 12.7% for all analytes in plasma and oral fluid. In conclusion, a sensitive and robust method was obtained, which fulfilled all validation criteria.     

Differentiation and identification of recombinant human erythropoietin and darbepoetin Alfa in equine plasma by LC-MS/MS for doping control

Recombinant human erythropoietin (rhEPO) and darbepoetin alfa (DPO) are protein-based drugs for the treatment of anemia in humans by stimulating erythrocyte production. However, these agents are abused in human and equine sports due to their potential to enhance performance. This paper describes the first method for differentiation and identification of rhEPO and DPO in equine plasma by liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS). The method comprised analyte extraction and enrichment by immunoaffinity separation with anti-rhEPO antibodies, dual digestion by trypsin and peptide-N-glycosidase F (PNGase F), and analysis by LC-MS/MS. Two unique deglycosylated tryptic peptides, (21)EAENITTGCAEHCSLNENITVPDTK (45) (T 5) from rhEPO and (77)GQALLVNSSQVNETLQLHVDK (97) (T 9) from DPO, were employed for differentiation and identification of rhEPO and DPO via LC retention times and major product ions. The limit of identification was 0.1 ng/mL for DPO and 0.2 ng/mL for rhEPO in equine plasma, and the limit of detection was 0.05 ng/mL for DPO and 0.1 ng/mL for rhEPO. Analyte carryover problem encountered was solved by adding 20% acetonitrile to the solvent of the sample digest to increase solubility of the peptides. This method was successfully applied to identification of DPO in plasma samples collected from a research horse following DPO administration and from racehorses out of competition in North America. Thus, it provides a powerful tool in the fight against blood doping with rhEPO and DPO in the horse racing industry.     

耐水解的硅烷偶联剂的制备及应用

用异丙醇部分取代γ-甲基丙烯酰氧基丙基三甲氧基硅烷(KH-570)的甲氧基,引入空间位阻较大的异丙氧基,使改性后的KH-570水解速率变慢。再用改性KH-570、八甲基环四硅氧烷(D4)与丙烯酸酯类单体乳液聚合,研究有机硅含量对聚合过程和乳胶膜透明性、力学性能等的影响。结果表明,引入异丙氧基后,有机硅耐水解性提高,反应结束仅少量凝胶,固含量在30%左右,转化率保持在80%以上;有机硅含量为21%时,乳液近似为牛顿流体,涂膜综合性能最好,吸水率最低为10%,断裂强度超过1MPa,断裂伸长率达475%。     

Determination of cyclic volatile methylsiloxanes in biota with a purge and trap method

The three cyclic volatile methylsiloxanes (cVMS), octamethylcyclotetrasiloxane (D4), decamethylcyclopentasiloxane (D5), and dodecamethylcyclohexasiloxane (D6), are recently identified environmental contaminants. Methods for the trace analysis of these chemicals in environmental matrices are required. A purge and trap method to prepare highly purified sample extracts with a low risk of sample contamination is presented. Without prior homogenization, the sample is heated in water, and the cVMS are purged from the slurry and trapped on an Isolute ENV+ cartridge. They are subsequently eluted with n-hexane and analyzed with GC/MS. The method was tested for eight different matrices including ragworms, muscle tissue from lean and lipid-rich fish, cod liver, and seal blubber. Analyte recoveries were consistent within and between matrices, averaging 79%, 68%, and 56% for D4, D5, and D6, respectively. Good control of blank levels resulted in limits of quantification of 1.5, 0.6, and 0.6 ng/g wet weight. The repeatability was 12% (D5) and 15% (D6) at concentrations 9 and 2 times above the LOQ. The method was applied to analyze cVMS in fish from Swedish lakes, demonstrating that contamination in fish as a result of long-range atmospheric transport is low as compared to contamination from local sources.     

Design and validation of a high-throughput matrix-assisted laser desorption ionization time-of-flight mass spectrometry method for quantification of hepcidin in human plasma

Disorders of iron metabolism affect over a billion people worldwide. The circulating peptide hormone hepcidin, the central regulator of iron distribution in mammals, holds great diagnostic potential for an array of iron-associated disorders, including iron loading (β-thalassemia), iron overload (hereditary hemochromatosis), and iron deficiency diseases. We describe a novel high-throughput matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry assay for quantification of hepcidin in human plasma. This assay involves enrichment using a functionalized MALDI chip, a novel solvent-detergent precipitation buffer, and quantification using a stable isotope labeled internal standard. The linear range of hepcidin in plasma was 1-120 nM, with a low limit of quantification (LOQ) (1 nM), high accuracy (<15% relative error (RE)), and high precision (intraday average 5.52-18.48% coefficient of variation (CV) and interday 9.32-14.83% CV). The assay showed strong correlation with an established hepcidin immunoassay (Spearman; R(2) = 0.839 n = 93 ethylenediaminetetraacetic acid (EDTA) plasma). A collection of normal healthy pediatric samples (range 3.8-32.5 ng/mL; mean 12.9 ng/mL; n = 119) showed significant differences from an adult collection (range 1.8-48.7 ng/mL; mean 16.1 ng/mL; n = 95; P = 0.0096). We discuss these preliminary reference ranges and correlations with additional parameters in light of the utility and limitations of hepcidin measurements as a stand-alone diagnostic and as a tool for therapeutic intervention.     

A validated stable isotope dilution liquid chromatography tandem mass spectrometry assay for the trace analysis of cocaine and its major metabolites in plasma.

A validated method has been developed for the simultaneous quantitation of cocaine and its major metabolites (ecgonine methyl ester, benzoylecgonine, and norcocaine) in rat plasma. The method is based upon the use of stable isotope dilution liquid chromatography/atmospheric pressure chemical ionization/tandem mass spectrometry. Previously reported methods do not have the sensitivity and specificity that can be attained with this method. Plasma samples required no cleanup apart from protein precipitation, and no derivatization was required. Selected reaction monitoring was performed on the transitions of m/z 200 to m/z 182 (ecgonine methyl ester), m/z 290 to m/z 168 (benzoylecgonine), m/z 304 to m/z 182 (cocaine), and m/z 290 to m/z 168 (norcocaine). The standard curves were linear over the range from 2 ng/mL (benzoylecgonine, cocaine, and norcocaine) or 5 ng/mL (ecgonine methyl ester) to 1000 ng/mL in rat plasma. The lower limit of quantitation (LLQ) for benzoylecgonine, cocaine, and norcocaine was 2 ng/mL, and for ecgonine methyl ester, the LLQ was 5 ng/mL for plasma. This simple, rapid, reliable, and sensitive method of quantitation had excellent accuracy and precision for the four analytes. The method was sensitive enough to permit a detailed study of the pharmacokinetics of cocaine and its metabolites after administration of a bolus intravenous dose to rats.     

Anti‐inflammatory effects of linagliptin in hemodialysis patients with diabetes

Inflammation and glycemic control are important prognosis‐related factors for hemodialysis (HD) patients; moreover, inflammation affects insulin secretion. Here, we evaluated the anti‐inflammatory effects of monotherapy with linagliptin—a dipeptidase‐4 inhibitor—in HD patients with type 2 diabetes. We examined 21 diabetic HD patients who were not receiving oral diabetes drugs or insulin therapy and with poor glycemic control (glycated albumin [GA] level, >20%). Linagliptin (5 mg) was administered to the patients daily. The levels of prostaglandin E2 (PGE2), interleukin‐6 (IL‐6), high‐sensitivity C‐reactive protein, GA, blood glucose, and active glucagon‐like peptide‐1 were determined before and 6 months after treatment. Body weight and serum levels of albumin, hemoglobin, total cholesterol, and low‐density lipoprotein cholesterol were also recorded before and after treatment. The levels of PGE2 and GA were significantly decreased 1 month after starting linagliptin therapy, whereas the IL‐6 levels were significantly decreased 6 months after starting linagliptin therapy. After 6 months of treatment, the PGE2 levels decreased from 188 ± 50 ng/mL to 26 ± 5 ng/mL; IL‐6 levels, from 1.5 ± 0.4 pg/mL to 0.6 ± 0.1 pg/mL; and GA levels, from 21.3% ± 0.6% to 18.0% ± 0.6%. Glucagon‐like peptide‐1 levels increased 2.5‐fold during the treatment. Over the 6‐month treatment period, body weight and levels of high‐sensitivity C‐reactive protein, blood glucose, albumin, hemoglobin, and cholesterol did not change; none of the patients exhibited hypoglycemia. The anti‐inflammatory effects of linagliptin monotherapy indicate that it may serve as a useful glucose control strategy for HD patients with diabetes.