TG Parameters Research Articles

Capsicum annuum extracts/β-cyclodextrin complexes

In this study, thermal analyses and Karl Fischer titration correlations on the new varieties of Capsicum annuum L. extracts/β-cyclodextrin complexes were performed. Two of seven studied Capsicum varieties containing the highest concentration of capsaicin (0.7 and 1.1 mg g−1 of dry sample) were used for obtaining Capsicum extracts/β-cyclodextrin complexes by co-crystallization method. Thermogravimetric analysis (TG) indicates mass losses with 5–5.7 % lower for the complexes in comparison with β-cyclodextrin, while differential scanning calorimetry analysis (DSC) shows a temperature peak shift to lower values, from 378.2 K (105 °C) for β-cyclodextrin to 355.2–361.2 K (82–88 °C) for complexes. On the other hand, Karl Fischer water titration (KFT) indicates a water concentration of 10.9–11.8 %, with 3.1–4.1 % lower than for β-cyclodextrin (14.9 %). The antioxidant activity of Capsicum extracts/β-cyclodextrin complexes has values comparable with standard antioxidant compound solutions, being significant longer time than the starting extracts. Statistically significant correlations between TG, DSC, and KFT main parameters [TG mass loss up to 423.2 K (150 °C), DSC peak temperature corresponding to water dissociation and KFT water content, and water reaction rate for “strongly-retained” water molecules partially replaced from the cyclodextrin cavity in the complexation process] were obtained, proving the formation of guest/host (Capsicum bioactive compounds/β-cyclodextrin) supramolecular systems.

Determining the impact of instrument variation and automated software algorithms on the TGT in hemophilia and normalized plasma

Despite increasing recognition as a more precise test of in vivo hemostatic conditions, standardization of the thrombin generation test (TGT) continues to hinder its development as routine clinical practice. Prior efforts largely focused on comparing the effects of experimental conditions and different reagents. Commercialized kits, instruments and software have been introduced to calculate the TG curve and its parameters. However, modified versions of the TGT continue to be used worldwide on a variety of microplate reader instruments and processed using individualized algorithms. No prior study has compared the effect of instrument choice and its inherent noise profile on the processing of the TG curve and its common endpoint parameters. Hemophilia A plasma supplemented with buffer or Factor VIII, mimicking hemophilic or normalized samples respectively, was monitored for thrombin generation after activation with TF on six different fluorescent microplate readers. Each instrument was optimized for TGT signal recording prior to testing. An automated software package containing various mathematical algorithms was utilized to compute the TG curves and parameters, and compare different TG processing approaches. Instruments produced unique noise profiles and end-point parameters that were incomparable in absolute signal terms. Similar relative hemophilic responses were obtained across various instruments when the normalized plasma sample was used as an internal standard. Smoothing algorithms corrected destructive instrument noise. Instrument-induced errors from numerical differentiation during TG curve processing cannot be eliminated by external calibrators, and require careful qualification of the instrument and implementation of noise-reducing software algorithms.

Body weight reduction and metformin: Roles in polycystic ovary syndrome

Background and objectives: Polycystic ovary syndrome (PCOS) is a common problem in women at fertile age. A prospective study was conducted to clarify the pathophysiological responses during an application of insulin sensitizer, metformin and weight reduction therapy at the Gynecology Center in Ohud hospital, in AL-Madinah AL-Munawarah, Kingdom of Saudi Arabia. Methodology: Twenty healthy women served as controls and 180 PCOS women divided into three groups participated in the study. First group was treated with Clomid citrate 100mg/day from the 2nd day of menses to the 6th day plus gonadotrophin from day three to the 13th. Group II was treated as group I plus 850mg metformin twice a day and group III was treated as group I plus weight reduction. Clinical symptoms, menstrual pattern, hirsutism, blood glucose, body mass index, waist-to-hip ratio, insulin, hormonal, and lipid profiles were assessed pre- and post treatment. Insulin resistance was calculated. Results: PCOS women had significantly higher values than the healthy women in most of the measurements. Metformin and weight reduction therapy resulted in a significant decrease in the fasting insulin, glucose/insulin ratio and HOMA-IR. Metformin and weight reduction therapy resulted in a significant decrease in the lipid parameters, testosterone, LH/FSH ratio, SHBG, and prolactin levels. HOMA-IR was significantly higher in women with PCOS. HOMA-IR was positively correlated with testosterone, estradiol, TG, total cholesterol and LDL-cholesterol parameters, and negatively correlated with HDL-cholesterol and FSH levels. Conclusion: Metformin therapy and weight reduction had favorable influences on the basic metabolic and hormonal profiles in women with PCOS and that metformin and lifestyle modification (weight reduction via diet restriction or exercise) resulted in a significantly greater weight loss than hormonal therapy alone. Metformin and weight reduction therapy decreased also hyperandrogenism and insulin resistance.

Toward Prediction of Thrombosis in Adolescent Girls On Estrogen Containing Contraceptives: Global Coagulation Profiles and Estrogen Gene Polymorphisms.

AbstractAbstract 2254 Background:Adolescent girls on oral contraceptive pills (OCPs) are at a higher risk for venous thromboembolism. OCP induced changes on coagulation and fibrinolytic pathways are complex with high inter-individual variability and factor assays are often non- informative. Global coagulation assays better delineate OCP induced coagulation changes and variability in such changes may be the result of differences in estrogen metabolism. Aims and Methods:Our study aims to: 1) Determine the prevalence of a hypercoagulable state after initiation of OCPs as measured by global coagulation assays and 2) Determine the contribution of variation in estrogen metabolism to this hypercoagulable state. In this ongoing prospective study, 36 healthy non-pregnant adolescent girls starting OCPs were enrolled after institutional review board approval. Samples were obtained prior to and after 3 months of initiating OCPs and were analyzed for tests such as prothrombin time (PT), activated partial thromboplastin time (APTT), clotting and anticoagulant factor assays, tissue factor initiated thromboelastography (TF-TEG), with t-PA (tissue plasminogen activator) modification for detecting fibrinolysis (tpa-TEG), thrombin generation +/−thrombomodulin (TM)(TG+/− TM) and estrone levels. All participants were genotyped for FV Leiden, F2 G20210, plasminogen activator inhibitor-1 (PAI-1) promoter polymorphism and 3 single nucleotide polymorphisms (SNPs) related to estrogen metabolism (estrogen receptor a (ESRa), UGT1A1, CYP3A5). SNP genotypes were compared based on coagulation tests, TG and TEG parameters and differences pre and on OCPs were examined.Results: Baseline:Median age of participants was 17 years (range 13–20). All were African American. Pre-OCP, the median FVIII activity was 160% (range 97–327) with normal values for other parameters. On OCPs:Routine tests:There were no significant differences in blood counts, von Willebrand factor (vWF) antigen, FVIII, vWF, protein C, S, Anti-thrombin, or PAI-1 activity on OCPs. The PT was shorter (10.5 ± 0.4 sec vs. 11 ± 0.4 sec, p= <0.001) on OCPs, and there were no differences in APTT.Thromboelastography:TF-TEG demonstrated higher maximum amplitude (67 ± 5.4 mm vs. 72 ± 7 mm, p= 0.024)) and G(10 ± 2.4 vs. 13± 4.3 dynes/cm, p=0.021) on OCPs. There were no differences in time to clot initiation or the rate of clot formation. Tpa-TEG did not reveal any differences in clot lysis at 30 and 60 minutes on OCPs (p= 0.8 and 0.4 respectively).Thrombin generation:TG using calibrated automated thrombography in corn trypsin inhibitor treated plasma demonstrated a shorter lag time [without TM: 2.3 min ± 0.4 vs. 1.8 ± 0.3min, p= 0.001, with TM: 2 ± 0.33min vs.1.7 ± 0.32 min, p=0.005], higher endogenous thrombin potential [without TM: 921± 289 nM.min vs. 1145 ± 350 nM.min, p=0.08, with TM: 659 ± 222 nM.min vs. 945 ± 368 nM.min, p=0.029], higher peak [without TM: 228 ± 53 nm vs. 291± 68 nm, p=0.012, with TM: 202 ± 58 nm vs. 268 ± 70 nm, p=0.023) and shorter time to peak(without TM: 4.7 ± 0.7 min vs. 3.7 ± 0.5 min, p= 0.001, with TM: 3.9 ± 0.4 min vs. 3.4 ± 0.4 min, p= 0.007)after being on OCPs for 3 months. Non-group O blood type and elevated FVIII at baseline did not correlate with ETP with or without TM after being on OCPs. Estrone levels did not correlate with peak thrombin generation pre-OCPs (R= 0.1, p=0.8).SNP genotyping:The ESRa (c.454–397T>C) polymorphism was present in the heterozygous state in 51% and homozygous state in 15% of the participants respectively. CT and CC genotype was associated with shorter lag time with TG-TM (2.7 ± 0.25 min vs. 1.7 ±0.14 min, p=0.026) but not with TF-TEG. The ESRa, UGT1A1 and CYP3A5 polymorphisms did not correlate with estrone levels or other coagulation parameters. As anticipated, FVL was absent in all and F2 G20210 (heterozygous) was present in one participant. Conclusions:In vitro thrombin generation and clot kinetics measured by global coagulation assays reveal a state of hypercoagulability in adolescent girls on OCPs not detected by routine coagulation testing. These differences appear to be likely caused by acquired activated protein C resistance as the addition of TM had less effect in patients on OCPs despite similar factor VIII activity. The presence of CT and CC genotype of the 454–397T>C polymorphism in the estrogen receptor-a, independent of estrone levels, correlated with hypercoagulability based on TG parameters but not TF-TEG. Disclosures:No relevant conflicts of interest to declare.

Thermogravimetric analysis of single-walled carbon nanotubes synthesized by induction thermal plasma

Abstract A standard procedure for thermogravimetric analysis (TG) of carbonaceous materials including single-walled carbon nanotubes was developed based on a statistical design to precisely study the effect of three main TG parameters: temperature ramp (TR, °C), initial mass (IM) of the sample (mg), and the rate of flowing gas (sccm) on the TG results. In addition, the effect of sampling including sample morphology and moisture content on TG were studied. The results of statistical design clearly showed that TG was affected by these three parameters and particularly by IM and TR. Interestingly, it was observed that the TG results are affected insufficiently by the sample morphology and low moisture content. This study also confirmed the potential of TG combined with high-resolution scanning electron microscopy to be a simple and straightforward method for purity evaluation of SWCNT-containing samples with a complex TG behavior such as those of induction thermal plasma grown. A complementary study on nano-...

Synthesis, spectroscopic characterization, pH-metric and thermal behavior on Co(II) complexes formed with 4-(2-pyridyl)-3-thiosemicarbazide derivatives

Four new cobalt (II) complexes of some thiosemicarbazides have been synthesized and spectrochemically characterized. The thiosemicarbazides are prepared by the addition of 4-(2-pyridyl)-3-thiosemicarbazide to phenyl isothiocyanate (H 2PPS), benzoyl isothiocyanate (H 2PBO), phenyl isocyanate (H 2APO) and 2-pyridyl isothiocyanate (H 2PPY). The complexes are characterized by elemental analysis, spectral (IR, 1H NMR and UV–Vis), thermal and magnetic measurements. The studies revealed that structures of complexes are of two types octahedral and tetrahedral. The octahedral complexes are of H 2PPS, which acts as di-anionic tetradentate SSNN and H 2APO acts as mono-anionic tridentate NON. The tetrahedral complexes are of H 2PBO, which acts as di-anionic tridentate NSO and H 2PPY acts as mono-anionic bidentate NS. From the modelling studies, the bond length, bond angle, HOMO, LUMO and dipole moment had been calculated to confirm the geometry of the ligands and their investigated complexes. From TG and DTA studies kinetic parameters are determined using Coats–Redfern and Horowitz–Metzger methods. From pH metric studies at 298, 303 and 308 K and μ (0.1, 0.15 and 0.2) in 50% dioxane–water mixture the protonation constants of the ligands, the stepwise stability constants of the complexes and their thermodynamic parameters are calculated.

Combustion Characteristics of Biomass and its Cellulose

The combustion characteristics of some biomass samples, such as rice straw and its cellulose, were investigated. Non-isothermal thermogravimetry, where the sample was heated in air and the temperature of which increased at a linear rate of 10°C/min, 20°C/min, 30°C/min, was used to investigate the combustion characteristics of the biomass samples. The differences in the TG-DTG-DSC curves of the samples were determined and discussed in detail. Conventional TG parameters, ignition index of samples were estimated which provided elaborate information on their basic combustion features. Results showed that cellulose with higher combustion characteristics.

Estudo de fatores pró-trombóticos e pró-inflamatórios na cardiomiopatia chagásica

The relationship between inflammatory and prothrombotic activity in chagas cardiomyopathy and in other etiologies is unclear. To study the profile of pro-thrombotic and pro-inflammatory markers in patients with Chagas' heart failure and compare them with patients of non-chagas etiology. Cross-sectional cohort. left ventricle ejection fraction (LVEF) < 45% and onset time to symptoms > one month. The patients were divided into two groups: group 1 (G1) - seropositive for Chagas - and group 2 (G2) - seronegative for Chagas. Pro-inflammatory factor: Ultra-sensitive CRP. Pro-thrombotic factors: thrombin-antithrombin factor, fibrinogen, von Willebrand factor antigen, plasma P-selectin and thromboelastography. Sample calculated for 80% power, assuming a standard deviation difference of 1/3; significant p if it is < 0.05. Fisher's exact test for categorical variables; unpaired Student's t-test for parametric continuous variables and Mann-Whitney test for nonparametric continuous variables. Between January and June 2008, 150 patients were included, 80 in G1 and 70 in G2. Both groups maintained the averages of high sensitivity CRP above baseline values, however, there was no significant difference (p = 0.328). The fibrinogen levels were higher in G2 than in G1 (p = 0.015). Among the thromboelastography variables, the parameters MA (p=0.0013), G (p=0.0012) and TG (p =0.0005) were greater in G2 than in G1. There is no evidence of greater pro-thrombotic status among patients with Chagas disease. The levels of fibrinogen and the MA, G and TG parameters of the thromboelastography point to pro-thrombotic status among non-chagas patients. Both groups had increased inflammatory activity.

Curing Reaction Kinetics of Epoxy/Anhydride/Silica Systems

Advances in the electricity industry have led to increasing demands for epoxy/anhydride/silica insulation systems. In this present study, the curing reaction kinetics of two epoxy systems are investigated using non-isothermal differential scanning calorimetry (DSC). Their mixtures were isothermally cured under vacuum at 130 °C for differing lengths of time, and their glass transition temperatures, Tg, activation energies, E A , and other parameters were determined by DSC. Interest in such systems centres on their industrial applications, for which reason it was decided to study high silica loadings, cured at 130° C; a curing temperature that was shown to be the most appropriate for these systems in all cases, as it prevented cracks and structural defects in the moulding production processes.

Increased Thrombin Generation Capacity in Septic Patients with DIC.

Variety clinical conditions may cause systemic activation of coagulation, ranging from insignificant laboratory changes to severe disseminated intravascular coagulation (DIC). DIC consists of widespread systemic activation of coagulation, resulting in diffuse fibrin deposition in small and midsize vessels. However, little is known about thrombin generation capacity in patients with DIC. To investigate the thrombin generation capacity, we measured thrombin generation in septic patients with DIC (n=20) and acute promyelocytic leukemia (APL)-induced DIC (n=5). Thrombin generation was determined by the Throbogram-Thrombinoscope assay (Thermo Electron Corporation, Netherlands). The analyzed TG parameters ware the peak of thrombin activity (Peak) and endogenous thrombin potential (ETP).The thrombin antithrombin complexes (TAT) levels were higher in both DIC patients as reported by others. In the septic patients with DIC, we found significant elevations in peak of thrombin activity and ETP as compared with normal controls (determined in 17 healthy males and 14 healthy female). However, the peak of thrombin activity and ETP levels were severely decreased by 60% n the APL patients with DIC. There was slightly correlation between the ETP and TAT levels in septic patients with DIC. Also, there was correlation between the ETP and bleeding tendency in APL patients with DIC.These results suggest that assess of thrombin generation capacity may be helpful in the making the diagnosis in septic patients with DIC. It appears that assess of ETP may contribute to evaluate bleeding tendency in APL patients with DIC.Sepsis with DICAPL with DICControls (n=31)Peak (nM)325.3 ± 55.5*88.2 ± 47.2*281.2 ± 40.9ETP (nM.min)1 ± 326.1*652.1 ± 274.5*1469.2 ± 227.3TAT (μg/ml)28.4 ± 17.5*22.5 ± 15.3*<3*(P<0.05) significantly different controls

In Vitro Effect of Danaparoid Sodium (Orgaran®) on Thrombin Generation after Minimal Tissue Factor Pathway Activation.

Introduction: Orgaran® (Org 10172) is a low molecular weight heparinoid which consists of natural sulphated glycosaminoglycans (heparan, dermatan, chondroitin sulphate). It has a mean molecular weight of approximately 6 kDa (4–10 kDa), an excellent bioavailability following subcutaneous administration and an anti-Xa/anti-IIa activity ratio superior to 22. It is the anticoagulant of choice in patients developping Heparin-Induced Thrombocytopenia (HIT), whereas its' use is also proposed for surgical thromboprophylaxis. Orgaran® has no effect on routine coagulation tests (aPTT, PT, TT). Thrombin generation test(TG) is a global clotting assay proven to be sensitive to the anticoagulant effect of LMWHs and specific FXa inhibitors (i.e. fondaparinux and BAY-597939). In this in vitro study, we determined the tissue factor (TF)-induced TG inhibition potency of Orgaran® using the Thrombogram-Thrombinoscope® assay.Materials and Methods: TG was assessed after TF pathway activation in Platelet Rich Plasma (PRP) (1.5x105 platelets/μl) using diluted thromboplastin (Dade Innovin®, 1:1000 final dilution). The clotting process is provoked by a physiologically relevant TF concentration. Orgaran® was added to control plasma from 8 healthy volunteers at five different final concentrations (0.2, 0.4, 0.6, 0.8 and 1IU anti-Xa/ml). TG was initiated by adding the triggering solution containing CaCl2 and the fluorogenic substrate. The analyzed TG parameters are the lag time, the maximal concentration of thrombin (Cmax), the time to reach Cmax (Tmax), the TG velocity and the endogenous thrombin potential (ETP).Results: Orgaran® prolonged significantly the lag time and the Tmax at a concentration over 0.40 IU anti-Xa/ml (p<0.05). At the lowest studied concentration (0.20 IU anti-Xa/ml), lag time and Tmax were only prolonged by 12%, whereas their maximal prolongation (around 50%) was observed at 1IU anti-Xa/ml. Furthermore, Orgaran® inhibited ETP, Cmax and TG velocity in an almost linear dose dependent manner. A significant inhibition of ETP, Cmax and TG velocity was obtained at concentrations superior to 0.20 IU anti-Xa/ml. (p<0.05). At the highest studied concentration (1IU anti-Xa/ml) Orgaran® suppressed all TG parameters by about 80% (Table 1).Conclusion: Orgaran® exhibited a significant inhibitory activity of in vitro TG. At concentrations achieved in clinical practice (prophylactic or therapeutic dose), Orgaran® modified in vitro TG profile while it has no effect on routine coagulation tests. Thus, TG assay is a sensitive method for monitoring Orgaran® and this test requires a clinical prospective evaluation.Table 1Determination of IC20 and IC50 anti-Xa inhibitory concentrations of Orgaran® on TG parametersLag TimeTmaxETPCmaxVelocityIC20(IU/ml)0.300.300.180.180.15IC50(IU/ml)0.83>10.300.500.351IU anti-Xa/ml53%47%68%76%84%IC: Inhibitory Concentration * or Concentration increasing 20% and 50% the lag time and the Tmax respectively

A successful dietary treatment fails to normalize plasma triglyceride postprandial response in type IV patients

The role of plasma triglycerides as a risk factor for cardiovascular disease is still under scrutiny. While recent studies have shown that postprandial triglyceridemia is an independent risk factor, normalization of fasting plasma triglycerides through modification of nutritional habits remains the primary approach in the treatment of hypertriglyceridemia. To address the issue of whether a satisfactory dietary regimen results in the control of postprandial lipemia, 53 type IV hypertriglyceridemic patients underwent an hypolipidemic diet for 3 months. All patients had a reduction of fasting lipid parameters (average TG: from 516±208 to 229±99 mg/dl; total cholesterol (Chol): from 261±42 to 213±40 mg/dl and HDL Chol: from 33±9 to 38±8 mg/dl). Taking plasma TG≤200 mg/dl as the target for dietary intervention 26 patients were classified as ‘responders’ while the remaining 27 were ‘non responders’. Even if fasting total TG, total Chol, HDL and LDL Chol were normal, both responders and non responders ( P<0.0001) showed an exaggerated postprandial response to an oral fat load as compared to controls (20 normolipidemic subjects). Also when 10 responders and 10 controls, all male, were matched for plasma TG (129±43 versus 121±41 mg/dl) and other lipid parameters, a statistically significant difference between the two groups was observed at the time of each of the postprandial tests ( P<0.0001) and for the area under the curve. The fact that the post prandial response is poorly modified by a dietary regimen, that effectively reduces plasma fasting TG, suggests that commonly used dietary regimens fail to restore a normal postprandial metabolism. Whether the cardiovascular risk for these patients is reduced after diet remains, therefore, to be addressed.

Quantitative TG/IR

The relationship of concentration-dependent integrated absorbances of evolved gases and specific chromatogram areas to TG and spectral parameters is examined in an attempt to quantify the spectral information provided by a TG/IR interface. The results suggest that, at present, this technique yields semi-quantitative information which complements the emerging role of this interface as a tool for qualitative evolved gas analysis. The effects of low spectral resolution and changing concentration profiles are factors that must be addressed before accurate spectral quantitation is possible.