Determination Of Serum Cholesterol Research Articles

High-sensitive detection of H2O2 in biological systems by persistent luminescent nanoprobes

Autofluorescence interference in the conventional fluorescence detection of hydrogen peroxide (H2O2) in biological systems represents a long-lasting problem in the field of biosensing. Here, we report a Cr3+, Y3+ co-doped ZnGaSnO4 (ZGSCY) nanoprobes which show long persistent luminescence (PL) that can be specifically enhanced by H2O2 without background fluorescence interference. The mesoporous organosilica are coated on the surface of ZGSCY to enhance the biocompatibility of the nanoprobes. Importantly, PL intensity of the nanoprobes can be further improved, because of the specific response of tetrasulfide bond in organosilica to H2O2. ZGSCY@MON show high-sensitive detection of H2O2 in living cells and human serum with the advantages of high specificity, low detection limit (91 nM), and wide linear range (0.5–60 μM, 60–400 μM). Furthermore, the extraordinary detection capability of H2O2 enables that the successful differentiate normal breast cells from breast cancer cells and the highly sensitive determination of serum glucose and cholesterol. We also clarified that the endogenous response originates from the UV-induced the interfacial electron transfer on ZGSCY regulated by H2O2 and exogenous response stems from the elimination of the adsorption of PL from the organosilica by H2O2. These findings open up a new effective way for autofluorescence-free detection of H2O2 in biological systems.

Importance in the determination of serum uric acid, cholesterol and triglyceride levels in pregnant women

The fundamental importance of the analytes lies in their role as primary biomarkers to identify possible conditions that may arise during the gestation process. Objective: To analytes the importance of determining uric acid, cholesterol and triglycerides in pregnant women. Methodology: The article was a literature review that focused on the synthesis and analysis of scientific articles related to the topic in question. The PRISMA method was used to search for information, which consisted of an exhaustive and systematic search for relevant data using appropriate search terms and strategies. Results: Thirteen articles were screened and selected for analysis, of which six were excluded because they focused on pregnant women, but with different analytes. From the standards, 7 articles were identified that met the methodology and were included in the article development analysis. Conclusions: The research evidenced that the evaluation of uric acid, cholesterol and triglyceride levels are a first source in preclinical diagnosis, however, among the most common pathologies such as preeclampsia there are approximately 66 predictive parameters being this an important part of prenatal care to promote a healthy pregnancy

An integrated microfluidic-based biosensor using a magnetically controlled MNPs-enzyme microreactor to determine cholesterol in serum with fluorometric detection

This work provides a microfluidic-based biosensor to determine total cholesterol in serum based on integrating the reaction/detection zone of a microfluidic chip of a magnetically retained enzyme microreactor (MREµR) coupled with the remote fluorometric detection through a bifurcated fiber-optic bundle (BFOB) connected with a conventional spectrofluorometer. The method is based on developing the enzymatic hydrolysis and oxidation of cholesterol at microscale size using both enzymes (cholesterol esterase (ChE) and cholesterol oxidase (ChOx)) immobilized on magnetic nanoparticles (MNPs). The biocatalyst reactions were followed by monitoring the fluorescence decreasing by the naphtofluorescein (NF) oxidation in the presence of the previous H2O2 formed. This microfluidic biosensor supposes the physical integration of a minimal MREµR as a bioactive enzyme area and the focused BFOB connected with the spectrofluorometer detector. The MREµR was formed by a 1 mm length of magnetic retained 2:1 ChE-MNP/ChOx-MNP mixture. The dynamic range of the calibration graph was 0.005–10 mmol L−1, expressed as total cholesterol concentration with a detection limit of 1.1 µmol L−1 (r2 = 0.9999, sy/x = 0.03, n = 10, r = 3). The precision expressed as the relative standard deviation (RSD%) was between 1.3 and 2.1%. The microfluidic-based biosensors showed a sampling frequency estimated at 30 h−1. The method was applied to determine cholesterol in serum samples with recovery values between 94.8 and 102%. The results of the cholesterol determination in serum were also tested by correlation with those obtained using the other two previous methods.Graphical abstract

Colorimetric determination of cholesterol based on the peroxidase-like activity of Cu-Salt-Fe nanozyme with multiple active sites.

Astrategy to enhance the peroxidase-like activity of the hemin compositeis presented. The Cu-Salt-Fe with enhanced activity was synthesized by one-step heat treatment and applied to the colorimetric determination of free cholesterol in human serum. Phosphate can act in complexing Cu2+ to form a carrier Cu-Floc with a large specific surface area. The coordination effect of Cu-Floc with hemin was used to disperse and load hemin to form Cu-Floc-Heminfrom whichCu-Salt-Fe was prepared. The Cu-Salt-Feexhibitsasynergistic catalytic effect of Cu-Salt, Fe2+, Fe3+, or Fe-Nx active sites in amplification of H2O2 oxidation. As expected, Cu-Salt-Fe triggered H2O2-mediated oxidation of 3,3',5,5'-tetramethylbenzidine (TMB), resulting in H2O2-dependent absorbance changes at 652nm. A cholesterol oxidase (ChOx)/Cu-Salt-Fe-TMB colorimetric sensing system exhibited excellent cholesterol determination performance in the range 5-1200μM with a detection limit of 2.73μM. Cholesterol recoveries from the three-level spiked serum ranged from 92.2 to 98.9% (RSD ≤ 5.4). This colorimetric sensing system not only provided a strategy for the determination of endogenous substances with H2O2 as an intermediate, but also provided a new design idea (carrier selection, activity enhancement method) for the development of other artificial enzymes with the same catalytic core.

Disruption of SMC-related genes promotes recombinant cholesterol esterase production in Burkholderia stabilis.

Burkholderia stabilis strain FERMP-21014 secretes cholesterol esterase (BsChe), which is used in clinical settings to determine serum cholesterol levels. Previously, we constructed an expression plasmid with an endogenous constitutive promoter to enable the production of recombinant BsChe. In this study, we obtained one mutant strain with 13.1-fold higher BsChe activity than the wild type, using N-methyl-N'-nitro-N-nitrosoguanidine as a mutagen. DNA-sequencing analysis revealed that the strain had lost chromosome 3 (∆Chr3), suggesting that the genes hindering BsChe production may be encoded on Chr3. We also identified common mutations in the functionally unknown BSFP_068720/30 genes in the top 10 active strains generated during transposon mutagenesis. As BSFP_068720/30/40 comprised an operon on Chr3, we created the BSFP_068720/30/40 disruption mutant and confirmed that each disruption mutant containing the expression plasmid exhibited ~ 16.1-fold higher BsChe activity than the wild type. Quantitative PCR showed that each disruption mutant and ΔChr3 had a ~ 9.4-fold higher plasmid copy number than the wild type. Structural prediction models indicate that BSFP_068730/40 is structurally homologous to the structural maintenance of chromosomes (SMC) protein MukBE, which is responsible for chromosome segregation during cell division. Conversely, BSFP_068720/30/40 disruption did not lead to a Chr3 drop-out. These results imply that BSFP_068720/30/40 is not a SMC protein but is involved in destabilizing foreign plasmids to prevent the influx of genetic information from the environment. In conclusion, the disruption of BSFP_068720/30/40 improved plasmid stability and copy number, resulting in exceptionally high BsChe production. KEY POINTS: • Disruption of BSFP_068720/30/40 enabled mass production of Burkholderia Che/Lip. • BSFP_068730/40 is an SMC protein homolog not involved in chromosome retention. • BSFP_068720/30/40 is likely responsible for the exclusion of exogenous plasmids.

Enzyme sensor for simultaneous determination of cholesterol, triglyceride and HDL cholesterol in serum.

A three-electrode lipid biosensor that simultaneously measures the total cholesterol (CHO), triglyceride (TG), and HDL cholesterol (HDL-C) in standard serum has been developed. The lipid biosensor is designed for clinical use where production cost, low sample requirement, portability, stability, and speed are high priorities. The device design filters out blood cells and lipoproteins from the serum, where the target molecules are catalyzed by enzymes encapsulated in carboxymethyl cellulose (CMC) to produce electron mediators, potassium ferrocyanide. These electron mediators were subsequently detected by amperometric determination. The sensor exhibit high selectivity towards the targets and can measure the target lipids in 4min with 10 µL of serum. Lastly, the device can be stored up to 18months with a minimal decrease in catalytic efficiency.

Expression and characterization of cholesterol oxidase with high thermal and pH stability from Janthinobacterium agaricidamnosum

Cholesterol oxidases (COXases) have a diverse array of applications including analysis of blood cholesterol levels, synthesis of steroids, and utilization as an insecticidal protein. The COXase gene from Janthinobacterium agaricidamnosum was cloned and expressed in Escherichia coli. The purified COXase showed an optimal temperature of 60 °C and maintained about 96 and 72% of its initial activity after 30 min at 60 and 70 °C, respectively. In addition, the purified COXase exhibited a pH optimum at 7.0 and high pH stability over the broad pH range of 3.0–12.0. The pH stability of the COXase at pH 12.0 was higher than that of highly stable COXase from Chromobacterium sp. DS-1. The COXase oxidized cholesterol and β-cholestanol at higher rates than other 3β-hydroxysteroids. The Km, Vmax, and kcat values for cholesterol were 156 μM, 13.7 μmol/min/mg protein, and 14.4 s−1, respectively. These results showed that this enzyme could be very useful in the clinical determination of cholesterol in serum and the production of steroidal compounds. This is the first report to characterize a COXase from the genus Janthinobacterium.

Screening of serum oxysterol biomarkers for colon cancer by liquid chromatography-tandem mass spectrometry

结肠癌(CC)是全球常见恶性肿瘤之一,发病率呈逐年上升趋势,目前没有有效的标志物用于疾病早期诊断和干预跟踪。胆固醇及其氧化衍生物氧固醇在众多恶性肿瘤发生发展中发挥关键作用。该研究采用液相色谱-串联质谱(LC-MS/MS)技术,对CC临床血清样本中胆固醇及相关10种氧固醇代谢物进行了定性定量分析,并采用偏最小二乘判别分析(PLS-DA)和正交偏最小二乘判别分析(OPLS-DA)进行多元统计分析,发现上述目标代谢物能够较好地区分CC组与健康对照组。为防止数据过拟合,该研究在PLS-DA模型各代谢物变量投影重要性(VIP)基础上,结合最优组分数及K-均值聚类结果,筛选得到3种代谢标志物。通过受试者操作特征曲线(ROC)的曲线下面积(AUC)分析,发现筛选得到的3种潜在标志物联合预测CC达到0.998,说明模型性能优良。GO(基因本体论)富集分析显示3种潜在标志物主要分布在内质网和包被囊泡上,参与胆固醇代谢、运输、低密度脂蛋白重塑等生物进程,发挥胆固醇运输活性和低密度脂蛋白颗粒受体结合的分子功能。KEGG(京都基因与基因组百科全书)通路分析显示3种潜在标志物富集于类固醇生物合成、PPAR(过氧化物酶体增殖物激活受体)信号通路及ABC(ATP结合盒)转运等通路上。该研究为寻找CC标志物及进一步阐明胆固醇及氧固醇在CC发病过程中的作用奠定了一定的基础。

Sensitive electrochemical detection of cholesterol using a portable paper sensor based on the synergistic effect of cholesterol oxidase and nanoporous gold

As a crucial biomarker for some diseases, the determination of cholesterol in human serum is of great significance for the diagnosis and prevention of these diseases. Hence, a portable cholesterol detection method is necessary for clinical and domestic applications. Here, a portable paper sensor was designed for cholesterol detection by modifying screen-printed electrode (SPE) with nanoporous gold (NPG). To achieve the reliable cholesterol detection, a synergistic strategy was proposed based on the oxidation of cholesterol by cholesterol oxidase (ChOx) and the reduction of oxidation product (H2O2) by NPG. Compared to existing electrochemical sensors, the resulting paper sensor exhibited a wider linear response in a range from 50 μM to 6 mM as well as a higher sensitivity of 32.68 μA mM−1 cm−2 with a lower detection limit of 8.36 μM. Moreover, the portable paper sensor presented strong anti-interference capability and stability in the detection of cholesterol in human serum, and the data detected by the portable paper sensor were consistent with that obtained by an automatic biochemical analyzer. These unique performances confirmed that the proposed paper sensor was a sensitive, reliable, and portable cholesterol detection method, making it a good choice for cholesterol detection.

Colorimetric Detection of Cholesterol Based on the Peroxidase‐Like Activity of Metal‐Organic Framework MIL‐101(Cr)

AbstractEfficient quantitative determination of cholesterol has important application value in drug testing and clinical diagnosis of cardiovascular diseases. In this work, a metal‐organic framework MIL‐101(Cr) (MIL=Materials of Institute Lavoisier) was synthesized and developed as a peroxidase mimic for colorimetric detection of cholesterol. Kinetic analysis indicated that the MIL‐101(Cr) nanoparticles showed a higher Vmax (2.27*10−7 MS−1) and a lower Km (0.07 mM) than the natural horseradish peroxidase (HRP). An effective colorimetric sensor has been proven to detect cholesterol. Based on the outstanding catalytic activity, the colorimetric sensor displayed a linear response for cholesterol in the concentration range from 1.1 μM to 22.9 μM and the detection limit as low as 0.86 μM. Furthermore, the proposed method based on MIL‐101(Cr) nanoparticles showed a favorable reproducibility and recovery. The sensor had been successfully applied to determine serum cholesterol level in mice and human, respectively.

ANTI-DIABETIC EFFECTS OF ETHANOL LEAF EXTRACT OF ONIONS (Allium cepa) ON ALLOXAN-INDUCED DIABETIC WISTAR ALBINO RATS

ANTI-DIABETIC EFFECTS OF ETHANOL LEAF EXTRACT OF ONIONS (Allium cepa) ON ALLOXAN-INDUCED DIABETIC WISTAR ALBINO RATS

An amperometric cholesterol biosensor based on immobilization of cholesterol oxidase onto titanium dioxide nanoparticles

Cholesterol is an important amphipathic molecule and essential structural constituent of all animal cells. It is made up of a hydrocarbon chain, four hydrocarbon ring structure and a hydroxyl group. It is also used in Vitamin D biosynthesis. Cholesterol is of two types: LDL (low-density lipoproteins, bad cholesterol) and HDL (high-density lipoproteins, good cholesterol. High cholesterol increase risk of coronary heart disease. Proposed work describes a unique approach of immobilizing cholesterol oxidase onto TiO2NPs, modified Pencil Graphite electrode and its application in construction of an amperometric biosensor for determination of serum cholesterol.

Magnetic Nanoparticle-Based Ligand Replacement Strategy for Chemical Luminescence Determination of Cholesterol.

Determination of serum cholesterol (Chol) is important for disease diagnosis, and has attracted great attention during the last few decades. Herein, a new magnetic nanoparticle-based ligand replacement strategy has been presented for chemical luminescence detection of Chol. The detection depends on ligand replacement from ferrocene (Fc) to Chol through a β-cyclodextrin (β-CD)–based host–guest interaction, which releases Fc–Hemin as a catalyst for the luminol/hydrogen peroxide chemical luminescence system. More importantly, the luminescence signal can be captured by the camera of a smartphone, thus realizing Chol detection with less instrument dependency. The limit of detection of this method is calculated to be 0.18 μM, which is comparable to some of the developed methods. Moreover, this method has been used successfully to quantify Chol from serum samples with a simple extraction process.

Usefulness of magnetically-controlled MNPs-enzymes microreactors for the fluorimetric determination of total cholesterol in serum

A new dynamic method containing a magnetically retained enzyme reactor (MRER) located in the reaction/detection zone of a flow injection (FI) system, has been used for the determination of total cholesterol in serum samples. The MRER was formed by a mixture ratio of 2/1 of immobilized enzymes cholesterol esterase (ChE) and cholesterol oxidase (COx) on magnetic nanoparticles (MNPs). The analytical signal is based on the fluorescence decreasing of the fluorophore naphtofluorescein (NF) due to its oxidation by the H2O2 formed in the enzymatic reactions. The dynamic range of the calibration graph was 1.55–100 mmol L−1 expressed as total cholesterol concentration (r2 = 0.9995, n = 5, r = 3), and the detection limit was 0.65 mmol L−1. The precision expressed as relative standard deviation (RSD %) was in the range of 4.7 and 0.6%. The method showed a sampling frequency of 10 h−1 and this method was applied to the determination of cholesterol in serum samples. The results were compared with those obtained using a previous automated clinical analyzer (ILab 600 analyzer). Also, recovery values ranging between 88.5 and 101.5% were achieved.

Nitrogen, Cobalt Co-doped Fluorescent Magnetic Carbon Dots as Ratiometric Fluorescent Probes for Cholesterol and Uric Acid in Human Blood Serum.

Detection of cholesterol and uric acid biomarkers is of great importance for clinical diagnosis of several serious diseases correlated with their variations in human blood serum. In this study, a new kind of well selective and highly sensitive ratiometric fluorescent probe for cholesterol and uric acid determination in human blood serum was innovatively developed on the basis of the inner filter effect (IFE) process of nitrogen, cobalt co-doped carbon dots (N,Co-CDs) with 2,3-diaminophenazine (DAP). DAP was the oxidative product during the oxidation reaction between o-phenylenediamine and H2O2. Fluorescent magnetic N,Co-CDs possessing blue emission and magnetic property were prepared through a facile one-pot hydrothermal strategy by using citric acid, diethylenetriamine, and cobalt(II) chloride hexahydrate as precursors. N,Co-CDs exhibited good ferromagnetic property and excellent optical properties even in extremely harsh environmental conditions, implying the huge potential applications of such N,Co-CDs in biological areas. On the basis of the IFE process between N,Co-CDs and DAP, N,Co-CDs were applied to establish ratiometric fluorescent probes for the indirect detection of cholesterol and uric acid that participated in enzyme-catalyzed H2O2-generation reactions. The established IFE-based fluorescent probes exhibited relatively low detection limits of 3.6 nM for cholesterol and 3.4 nM for uric acid, respectively. The fluorescent probe was successfully utilized for the determination of cholesterol and uric acid in human blood serum with satisfying results, which provided an informed perspective on the applications of such doped CDs to explore the specific and sensitive nanoprobe in disease diagnoses and clinical therapy.

Tetrahydropalmatine Prevents High-Fat Diet-Induced Hyperlipidemia in Golden Hamsters (Mesocricetus Auratus).

BackgroundHyperlipidemia is a major cause of atherosclerotic cardiovascular disease. Tetrahydropalmatine (THP) can exhibit hepatoprotective, anti-arrhythmic, and anti-inflammatory activities. The mechanism of THP on the hyperlipidemia remains unknown; therefore, the present study explored the role of THP in hyperlipidemia.Material/MethodsWe established an animal model of hyperlipidemia by high-fat diet (HFD) feeding. Blood samples were obtained for determination of serum cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL-c), pro-inflammatory cytokines, and CYP7A1 expression. Histology was performed and inflammation was detected in the liver using hematoxylin-eosin (HE) staining and enzyme-linked immunosorbent assay (ELISA), respectively. The mRNA and protein levels of TLR4 and TRAF-6 were determined by quantitative real-time PCR (qPCR) and Western blot, respectively.ResultsTHP suppressed hepatic lipid accumulation and reduced serum levels of TC, TG, LDL-c, and HDL-c in HFD-fed golden hamsters. THP increased cholesterol 7 α-hydroxylase (CYP7A1) expression and prevented inflammation by the limited reduction in interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) expressions in serum and liver. THP slightly increased the ratio of the body/liver weight. THP inhibited the mRNA and protein levels of Toll-like receptor 4 (TLR4) and TNF-receptor associated factor-6 (TRAF-6).ConclusionsThese results suggest that THP attenuates hyperlipidemia by multiple effects, including hepatoprotective and anti-inflammatory effects. Moreover, THP also suppressed the expressions of TLR4 and TRAF-6 in golden hamsters.

Efficacy of compound Dendrobium on PI3K/AKT/eNOS signaling pathway in hypertensive rats induced by "dietary disorders"

To observe the efficacy of compound Dendrobium on Sprague Dawley rats (SD) hypertension model induced by "dietary disorders" and its relevant mechanism, totally 50 SD rats were fed with high-sugar, high-fat diet and alcohol for four weeks. According to the blood pressure after modeling, the rats were divided into model group, valsartan group (8 mg·kg⁻¹), low, medium and high-dose Dendrobium candidum compound groups (1.65, 3.30, 5.00 g·kg⁻¹), with 10 rats in each group, and the other 10 SD rats were also taken as the normal group. After four weeks of treatment, blood pressure was measured. Orbital blood was collected for the determination of serum cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-c), high-density lipoprotein cholesterol (HDL), calculation of atherosclerosis index (AI). Nitric acid reductase method was used to detect serum nitric oxide (NO); the levels of serum endothelin-1 (ET-1) and intercellular adhesion molecule-1 (ICAM-1) were measured by ELISA. The rats were put to death after the last administration, and the protein expressions of PI3K/AKT/eNOS in thoracic aorta of rats in each group were detected by Western blot. The aorta was separated and stained with hematoxylin-eosin (HE) to observe the changes in the endothelium and blood vessels in the thoracic aorta. Masson staining was used to observe the formation of aortic collagen. The expressions of nitric oxide synthase (eNOS) and ICAM-1 in aortic endothelial cells were observed by immunohistochemistry. In contrast, the results show D. candidum compound can significantly reduce the blood pressure in hypertensive rats, increase HDL-c, and reduce AI, while increasing serum NO content, decreasing ET-1 and ICAM-1 levels and promoting PI3K/AKT/NOS protein expressions. The lesion degree of the D. candidum compound group was reduced, and the collagen deposition was significantly reduced. Meanwhile, D. candidum compound can significantly increase the expression of eNOS, and reduce the formation of ICAM-1.Therefore, D. candidum compound has an obvious antihypertensive effect on hypertensive rats, which may be related to the increase in PI3K/AKT/eNOS signaling pathways and NO generation, the inhibition of the secretion of ICAM-1 and ET-1, the protection of the vascular endothelium and the improvement of aortic disease.

Extracellular cholesterol oxidase production by Streptomyces aegyptia, in vitro anticancer activities against rhabdomyosarcoma, breast cancer cell-lines and in vivo apoptosis

In recent years, microbial cholesterol oxidases have gained great attention due to its widespread use in medical applications for serum cholesterol determination. Streptomyces aegyptia strain NEAE-102 exhibited high level of extracellular cholesterol oxidase production using a minimum medium containing cholesterol as the sole source of carbon. Fifteen variables were screened using Plackett–Burman design for the enhanced cholesterol oxidase production. The most significant variables affecting enzyme production were further optimized by using the face-centered central composite design. The statistical optimization resulted in an overall 4.97-fold increase (15.631 UmL−1) in cholesterol oxidase production in the optimized medium as compared with the unoptimized medium before applying Plackett Burman design (3.1 UmL−1). The purified cholesterol oxidase was evaluated for its in vitro anticancer activities against five human cancer cell lines. The selectivity index values on rhabdomyosarcoma and breast cancer cell lines were 3.26 and 2.56; respectively. The in vivo anticancer activity of cholesterol oxidase was evaluated against Ehrlich solid tumor model. Compared with control mice, tumors growth was significantly inhibited in the mice injected with cholesterol oxidase alone, doxorubicin alone and cholesterol oxidase/doxorubicin combination by 60.97%, 72.99% and 97.04%; respectively. These results demonstrated that cholesterol oxidase can be used as a promising natural anticancer drug.

The indices of metabolismin rats with periodontitis on the background of hyper- and hypothyroidism

Introduction. The multifaceted action of thyroid hormones on the rate of metabolic processes reflected on the tissues of periodontium has been known for a long time. In this case, the prevalence of periodontitis in the population, the complexity of the implementation of prevention and treatment of the disease, ambiguity in the interpretation of the main pathogenetic mechanisms makes this problem extremely relevant.The aim of the study – to learn the indices of metabolismin blood serum of rats with periodontitis without concomitant pathology and against the background of hyper- and hypothyroidism.Research Methods. The study was carried out on 48 white non-linear male rats. Determination of glucose, total protein, albumin, urea, creatinine, total cholesterol, α-cholesterol and β-cholesterol in serum was carried out on a semi-automatic biochemical analyzer Humalyzer 2000 (Human, Germany).Results and Discussion. Experimental periodontitis is accompanied by a decrease in the concentration of glucose in the blood serum, hypoalbuminemia, an increase in the concentration of urea, total cholesterol, β-cholesterol and a decrease in the concentration of α-cholesterol. The imbalance of thyroid hormones has a multifaceted effect on metabolism in experimental periodontitis. Thus, in rats with periodontitis in case of hyperthyroidism, the concentration of glucose and total protein increased, albumin concentration decreased, urea concentration increased, total cholesterol and α-cholesterol concentrations decreased, and no significant changes in β-cholesterol concentration were observed. In rats with periodontitis, combined with hypothyroidism, glucose concentration decreased, total protein concentration increased, albumin concentration decreased, urea concentration increased, total cholesterol and β-cholesterol concentrations increased, and the concentration of α-cholesterol decreased.Conclusions. Reasonable changes in all major spectra of metabolism – carbohydrate, protein and lipid in case of experimental periodontitis indicate that periodontitis is a local process that affects the general state of the organism. The imbalance of thyroid hormones has a pronounced effect on the overall metabolic processes, especially on proatherogenic changes in serum, which are more pronounced in case of an experimental periodontitis in the background of hypothyroidism.

CCQM K6.2 determination of total cholesterol in human serum

Cholesterol is one of the most frequently measured substances in human blood/serum to assist in assessing the health status of individuals. Because of its clinical significance, CCQM-K6 determination of cholesterol in serum was completed in 2000 as one of the first key comparison (KC) studies performed within the Organic Analysis Working Group (OAWG). The first subsequent KC for cholesterol, CCQM-K6.1, was completed in 2001. Measurements for this second subsequent, CCQM-K6.2, were completed in 2012. These subsequent comparisons were conducted to enable CCQM members that had not participated in earlier studies to demonstrate their capabilities to measure a nonpolar (pKow < −2), low molecular mass (100 g/mol to 500 g/mol) metabolite in human serum at relatively high concentrations (1 mg/g to 3 mg/g) found in normal populations. Successful participation in CCQM-K6.2 demonstrated capabilities in analysis of complex biological matrices including sample preparation (extraction, derivatization), LC or GC separation, and quantification using an isotope dilution mass spectrometry approach.Normally in a subsequent KC, no key comparison reference value (KCRV) would be established and assessment of performance would be via the deviation of participants' results to the anchor institute's results, adjusted to account for the anchor's performance in the original comparison versus its KCRV. Due to the very long-time period since the original key comparison, the OAWG decided that this did not represent the best approach to assess performance in what is a relatively complex measurement. Given the excellent agreement between the anchor institute's results and robust consensus summary of the participants' values, the reference value for this study was taken as the anchor institute's result and treated as a 'KCRV'. Seven of the nine participants demonstrated agreement with the reference value.Main textTo reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm.org/.The final report has been peer-reviewed and approved for publication by the CCQM, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).