Detection of sympathetic denervation defects in Fabry disease by hybrid [11C]meta-hydroxyephedrine positron emission tomography and cardiac magnetic resonance.

BACKGROUND: Myocardial glycosphingolipid accumulation in patients with Fabry disease (FD) causes biochemical and structural changes. This study aimed to investigate sympathetic innervation in FD using hybrid cardiac positron emission tomography (PET)/magnetic resonance imaging (MRI). METHODS AND RESULTS: Patients with different stages of Fabry disease were prospectively enrolled to undergo routine CMR at 1.5T, followed by 3T hybrid cardiac PET/MRI with [11C]meta-hydroxyephedrine ([11C]mHED). Fourteen patients with either no evidence of cardiac involvement (n = 5), evidence of left ventricular hypertrophy (LVH) (n = 3), or evidence of LVH and fibrosis via late gadolinium enhancement (LGE) (n = 6) were analyzed. Compared to patients without LVH, patients with LVH or LVH and LGE had lower median T1 relaxation times (ms) at 1.5 T (1007 vs. 889 vs. 941 ms, p = 0.003) and 3T (1290 vs. 1172 vs. 1184 p = .014). Myocardial denervation ([11C]mHED retention < 7%·min) was prevalent only in patients with fibrosis, where a total of 16 denervated segments was found in two patients. The respective area of denervation exceeded the area of LGE in both patients (24% vs. 36% and 4% vs. 32%). However, sympathetic innervation defects ([11C]mHED retention ≤ 9%·min) occurred in all study groups. Furthermore, a reduced sympathetic innervation correlated with an increased left ventricular mass (p = .034, rs = - 0.57) and a reduced global longitudinal strain (GLS) (p = 0.023, rs = - 0.6). CONCLUSION: Hybrid cardiac PET/MR with [11C]mHED revealed sympathetic innervation defects, accompanied by impaired GLS, in early stages of Fabry disease. However, denervation is only present in patients with advanced stages of FD showing fibrosis on CMR.

Evaluating the behavior and principle of deep eutectic solvent on ephedrine-type alkaloid extraction from Ephedrae Herba.

In this study, deep eutectic solvent (DES), as a new green solvent, was used to extract bioactive alkaloids from Ephedrae Herba using supersonic extraction. In a variety of tested hydrophilic and hydrophobic DESs, DES composed of choline chloride and xylitol was proved to be the most efficient solvent. Factors affecting extraction efficiency, including the mole ratio of hydrogen bond acceptor/hydrogen bond donor, water contention, and solid/liquid ratio, were optimized individually. Under optimal conditions, the yield of ephedrine (EP) and pseudoephedrine obtained using this new method was 14.24 and 4.32 mg/g, respectively, which was higher than that using the traditional solvent (acidified water and methanol). Furthermore, the extraction mechanism of DES and EP was investigated using molecular dynamics simulation study. Structural properties such as radial distribution functions and average number of hydrogen bonds were then computed. The results showed that hydrogen bonds and van der Waals forces are important driving forces of extraction; in addition, the hydrogen bonds between the Cl atom of choline chloride and N atom of EP played a dominant part in the extraction process. Based on the extraction principle, the extraction method using choline chloride as extraction solvent was also discussed.

Does quantification of [11C]meta-hydroxyephedrine and [13N]ammonia kinetics improve risk stratification in ischemic cardiomyopathy.

BACKGROUND: In ischemic cardiomyopathy patients, cardiac sympathetic nervous system dysfunction is a predictor of sudden cardiac arrest (SCA). This study compared abnormal innervation and perfusion measured by [11C]meta-hydroxyephedrine (HED) vs [13N]ammonia (NH3), conventional uptake vs parametric tracer analysis, and their SCA risk discrimination. METHODS: This is a sub-study analysis of the prospective PAREPET trial, which followed ischemic cardiomyopathy patients with reduced left ventricular ejection fraction (LVEF ≤ 35%) for events of SCA. Using n = 174 paired dynamic HED and NH3 positron emission tomography (PET) scans, regional defect scores (%LV extent × severity) were calculated using HED and NH3 uptake, as well as HED distribution volume and NH3 myocardial blood flow by kinetic modeling. RESULTS: During 4.1 years follow-up, there were 27 SCA events. HED defects were larger than NH3, especially in the lowest tertile of perfusion abnormality (P < .001). Parametric defects were larger than their respective tracer uptake defects (P < .001). SCA risk discrimination was not significantly improved with parametric or uptake mismatch (AUC = 0.73 or 0.70) compared to HED uptake defect scores (AUC = 0.67). CONCLUSION: Quantification of HED distribution volume and NH3 myocardial blood flow produced larger defects than their respective measures of tracer uptake, but did not lead to improved SCA risk stratification vs HED uptake alone.

Combination of Ephedra sinica stems and Terminalia chebula fruits produces new ephedrine derivatives in vivo that diminish the permeability to BBB while retaining airway dilation and hepatoprotective effects.

ETHNOPHARMACOLOGICAL RELEVANCE: The stems of Ephedra sinica and the fruits of Terminalia chebula are combined using in traditional Mongolian medicine formula "Gurigumu-7" for liver diseases. E. sinica stems contains ephedrine with broncho-dilatory activity. However, ephedrine can pass through the blood-brain barrier (BBB) and excite the central nervous system (CNS) to cause insomnia and restlessness. AIM OF THE STUDY: The present study was to investigate the structures and bioactivities of new compounds formed in vivo after co-administration of E. sinica stems and T. chebula fruits. MATERIALS AND METHODS: Pharmacokinetic investigation was carried out in rats. A parallel artificial membrane permeability measurement system was used to determine BBB permeability. Ex vivo experiments using tracheal rings of guinea pig was performed to examine the tracheal relaxation effect. In vivo hepatoprotective tests were carried out in Tg (fabp10a: dsRed) liver transgenic zebrafish. The fluorescent probe, 2,7-dichlorodihydrofluorescein diacetate, was used to measure reactive oxygen species, and UHPLC-MS was used to determine glutathione concentrations after derivatization with N-ethylmaleimide. RESULTS: New ephedrine derivatives (1 and 2) formed in vivo and reached their maximum serum concentrations at 0.5 h after administration of the two herbal drugs. Compounds 1 and 2 showed lower BBB permeability than ephedrine, suggesting that they have less adverse effects on the CNS. Compounds 1 and 2 relaxed the tracheal rings and had strong hepatoprotective effect on transgenic zebrafish with liver specific expression of RFP. Compounds 1 and 2 significantly reduced the level of reactive oxygen species while increasing that of glutathione in thioacetamide-treated zebrafish, which might be the hepatoprotective mechanism. CONCLUSION: These results provided evidences that the chemical constituents in various herbal drugs in a medicinal formula can interact to generate new compounds with fewer side effects and increased or additive bioactivity.

A Rapid and Feasible 1H-NMR Quantification Method of Ephedrine Alkaloids in Ephedra Herbal Preparations.

A highly specific and sensitive proton nuclear magnetic resonance (1H-NMR) method has been developed for the quantification of ephedrine alkaloid derivatives in Ephedra herbal commercial prescriptions. At the region of δ 4.0 to 5.0 ppm in the 1H NMR spectrum, the characteristic signals are separated well from each other, and six analogues in total, methylephedrine (ME), ephedrine (EP), norephedrine (NE), norpseudoephedrine (NP), pseudoephedrine (PE), and methylpseudoephedrine (MP) could be identified. The quantities of these compounds are calculated by the relative ratio of the integral values of the target peak for each compound to the known concentrations of the internal standard anthracene. The present method allows for a rapid and simple quantification of ephedrine alkaloid derivatives in Ephedra-related commercial prescriptions without any preliminary purification steps and standard compounds, and accordingly it can be a powerful tool to verify different Ephedra species. In comparison to conventional chromatographic methods, the advantages of this method include the fact that no standard compounds are required, the quantification can be directly performed on the crude extracts, a better selectivity for various ephedrine alkaloid derivatives, and the fact that a very significant time-gain may be achieved.

Nine prohibited stimulants found in sports and weight loss supplements: deterenol, phenpromethamine (Vonedrine), oxilofrine, octodrine, beta-methylphenylethylamine (BMPEA), 1,3-dimethylamylamine (1,3-DMAA), 1,4-dimethylamylamine (1,4-DMAA), 1,3-dimethylbutylamine (1,3-DMBA) and higenamine.

BACKGROUND: Weight loss and sports supplements containing deterenol have been associated with serious adverse events including cardiac arrest. OBJECTIVE: To determine the presence and quantity of experimental stimulants in dietary supplements labeled as containing deterenol sold in the United States. METHODS: Dietary supplements available for sale in the US and labeled as containing deterenol or one of its synonyms (e.g., isopropylnorsynephrine and isopropyloctopamine) were purchased online. For each brand, one container or subsample was analyzed by NSF International (Ann Arbor, MI) and one container or subsample by the Netherland's National Institute for Public Health and the Environment (RIVM, Bilthoven, The Netherlands). When differences existed between the two containers or subsamples of the same brand, both products were reanalyzed by Sciensano (Brussels, Belgium). NSF International carried out qualitative and quantitative analyses using ultra-high-performance liquid chromatography (UHPLC) quadrupole-Orbitrap mass spectrometry. RIVM performed qualitative and quantitative analysis using UHPLC quadrupole time-of-flight mass spectrometry. Sciensano carried out qualitative analysis using UHPLC quadrupole-Orbitrap mass spectrometry. RESULTS: Seventeen brands of supplements were analyzed. Many brands included more than one prohibited stimulant in the same product: 4 brands (24%, 4/17) included 2 stimulants, 2 (12%, 2/17) combined 3 stimulants, and 2 (12%, 2/17) combined 4 stimulants. The range of quantities per recommended serving size of the 9 stimulants detected were 2.7 mg to 17 mg of deterenol; 1.3 mg to 20 mg of phenpromethamine (Vonedrine); 5.7 mg to 92 mg of beta-methylphenylethylamine (BMPEA); 18 mg to 73 mg of octodrine; 18 mg to 55 mg of oxilofrine; 48 mg of higenamine; 17 mg of 1,3-dimethylamylamine (1,3-DMAA); 1.8 mg to 6.6 mg of 1,3-dimethylbutylamine (1,3-DMBA); and 5.3 mg of 1,4-dimethylamylamine (1,4-DMAA). CONCLUSION: Weight loss and sports supplements listing deterenol as an ingredient contained 9 prohibited stimulants and 8 different mixtures of stimulants, with as many as 4 experimental stimulants per product. These cocktails of stimulants have never been tested in humans and their safety is unknown.

Screening and evaluation of anti-SARS-CoV-2 components from Ephedra sinica by ACE2/CMC-HPLC-IT-TOF-MS approach.

Traditional Chinese medicines played an important role in the treatment of COVID-19 in 2020. Ephedra sinica, one of the major constituent herbs of multi-component herbal formula, has been widely used to treat COVID-19 in China. However, its active components are still unclear. The objectives of this study are to screen and evaluate active components from the traditional Chinese medicine Ephedra sinica for the treatment of COVID-19. In our study, we established an ACE2/CMC bioaffinity chromatography model, and then developed an ACE2/CMC-HPLC-IT-TOF-MS system for the active compounds screening and identification from Ephedra sinica extract. We performed molecular docking and surface plasmon resonance (SPR) assays to assess the binding characteristics (binding mode and KD value). We used CCK-8 staining to assess the toxicity of screened compounds, and also used SARS-CoV-2 pseudovirus to observe the viropexis effect of screened compounds in ACE2h cells. In this current work, one fraction was fished out, separated and identified as ephedrine (EP), pseudoephedrine (PEP), and methylephedrine (MEP). Binding assays showed that the three compounds could bind with ACE2 in a special way to some amino acid residues, similar to the way SARS-CoV-2 bound with ACE2. Additionally, the three compounds, especially EP, can inhibit the entrance of SARS-CoV-2 spike pseudovirus into ACE2h cells because they can reduce the entrance ratio of pseudovirus in the pseudovirus model. Overall, the ACE2/CMC-HPLC-IT-TOF-MS system was established and verified to be suitable for ACE2-targeted bioactive compound screening. EP, PEP, and MEP with ACE2-binding features were screened out from Ephedra sinica, and acted as blockers inhibiting SARS-CoV-2 spike pseudovirus entering ACE2h cells.

Localization of Major Ephedra Alkaloids in Whole Aerial Parts of Ephedrae Herba Using Direct Analysis in Real Time-Time of Flight-Mass Spectrometry.

Mass spectrometry-based molecular imaging has been utilized to map the spatial distribution of target metabolites in various matrixes. Among the diverse mass spectrometry techniques, matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) is the most popular for molecular imaging due to its powerful spatial resolution. This unparalleled high resolution, however, can paradoxically act as a bottleneck when the bio-imaging of large areas, such as a whole plant, is required. To address this issue and provide a more versatile tool for large scale bio-imaging, direct analysis in real-time-time of flight-mass spectrometry (DART-TOF-MS), an ambient ionization MS, was applied to whole plant bio-imaging of a medicinal plant, Ephedrae Herba. The whole aerial part of the plant was cut into 10-20 cm long pieces, and each part was further cut longitudinally to compare the contents of major ephedra alkaloids between the outer surface and inner part of the stem. Using optimized DART-TOF-MS conditions, molecular imaging of major ephedra alkaloids of the whole aerial part of a single plant was successfully achieved. The concentration of alkaloids analyzed in this study was found to be higher on the inner section than the outer surface of stems. Moreover, side branches, which are used in traditional medicine, represented a far higher concentration of alkaloids than the main stem. In terms of the spatial metabolic distribution, the contents of alkaloids gradually decreased towards the end of branch tips. In this study, a fast and simple macro-scale MS imaging of the whole plant was successfully developed using DART-TOF-MS. This application on the localization of secondary metabolites in whole plants can provide an area of new research using ambient ionization mass spectroscopy and an unprecedented macro-scale view of the biosynthesis and distribution of active components in medicinal plants.

[11C]meta-hydroxyephedrine PET evaluation in experimental pulmonary arterial hypertension: Effects of carvedilol of right ventricular sympathetic function.

BACKGROUND: Little is known about the sequelae of chronic sympathetic nervous system (SNS) activation in patients with pulmonary arterial hypertension (PAH) and right heart failure (RHF). We aimed to, (1) validate the use of [11C]-meta-hydroxyephedrine (HED) for assessing right ventricular (RV) SNS integrity, and (2) determine the effects of ß-receptor blockade on ventricular function and myocardial SNS activity in a PAH rat model. METHODS: PAH was induced in male Sprague-Dawley rats (N = 36) using the Sugen+chronic hypoxia model. At week 5 post-injection, PAH rats were randomized to carvedilol (15 mg·kg-1·day-1 oral; N = 16) or vehicle (N = 16) for 4 weeks. Myocardial SNS function was assessed with HED positron emission tomography(PET). RESULTS: With increasing PAH disease severity, immunohistochemistry confirmed selective sympathetic denervation within the RV and sparing of parasympathetic nerves. These findings were confirmed on PET with a significant negative relationship between HED volume of distribution(DV) and right ventricular systolic pressure (RVSP) in the RV (r = -0.90, p = 0.0003). Carvedilol did not reduce hemodynamic severity compared to vehicle. RV ejection fraction (EF) was lower in both PAH groups compared to control (p < 0.05), and was not further reduced by carvedilol. Carvedilol improved SNS function in the LV with significant increases in the HED DV, and decreased tracer washout in the LV (p < 0.05) but not RV. CONCLUSIONS: PAH disease severity correlated with a reduction in HED DV in the RV. This was associated with selective sympathetic denervation. Late carvedilol treatment did not lead to recovery of RV function. These results support the role of HED imaging in assessing SNS innervation in a failing right ventricle.

Reproducible Quantification of Regional Sympathetic Denervation with [11C]meta-Hydroxyephedrine PET Imaging.

BACKGROUND: Regional cardiac sympathetic denervation is predictive of sudden cardiac arrest in patients with ischemic cardiomyopathy. The reproducibility of denervation scores between automated software programs has not been evaluated. This study seeks to (1) compare the inter-rater reliability of regional denervation measurements using two analysis programs: FlowQuant® and Corridor4DM®; (2) evaluate test-retest repeatability of regional denervation scores. METHODS: N = 190 dynamic [11C]meta-hydroxyephedrine (HED) PET scans were reviewed from the PAREPET trial in ischemic cardiomyopathy patients with reduced left ventricular ejection fraction(LVEF ≤ 35%). N = 12 scans were excluded due to non-diagnostic quality. N = 178 scans were analyzed using FlowQuant and Corridor4DM software, each by two observers. Test-retest scans from N = 20 patients with stable heart failure were utilized for test-retest analysis. Denervation scores were defined as extent × severity of relative uptake defects in LV regions with < 75% of maximal uptake. Results were evaluated using intraclass correlation coefficient (ICC) and Bland-Altman coefficient of repeatability (RPC). RESULTS: Inter-observer, inter-software, and test-retest ICC values were excellent (ICC = 94% to 99%) and measurement variability was small (RPC < 11%). Mean differences between observers ranged .2% to 1.1% for Corridor4DM (P = .28), FlowQuant (P < .001), and between software programs (P < .001). Kaplan-Meier analysis demonstrated HED scores from both programs were predictive of SCA. CONCLUSION: Inter-rater reliability for both analysis programs was excellent and test-retest repeatability was consistent. The minimal difference in scores between FlowQuant and Corridor4DM supports their use in future trials.

Application of a chiral high-performance liquid chromatography-tandem mass spectrometry method for the determination of 13 related amphetamine-type stimulants to forensic samples: Interpretative hypotheses.

Interpretation of amphetamine-type stimulant (ATS) findings in urine samples can be challenging without chiral information. We present a sensitive enantioselective high-performance liquid chromatography-tandem mass spectrometry method for the quantification of (R)-amphetamine, (S)-amphetamine, (R)-methamphetamine, (S)-methamphetamine, (1R,2R)-pseudoephedrine, (1S,2S)-pseudoephedrine, (1R,2S)-ephedrine, (1S,2R)-ephedrine, (1R,2S)-norephedrine, (1S,2R)-norephedrine, (R)-cathinone, (S)-cathinone, and (1S,2S)-norpseudoephedrine (cathine) in urine. The method was successfully applied to more than 100 authentic urine samples from forensic casework. In addition, samples from a controlled self-administration of (1S,2S)-pseudoephedrine (Rinoral, 1200 mg within 6 days) were analyzed. The results strengthen the hypothesis that (1R,2S)-norephedrine is a minor metabolite of amphetamine and methamphetamine. We suggest cathine and (1S,2R)-norephedrine as minor metabolites of amphetamine racemate in humans. Small methamphetamine concentrations detected in samples with high concentrations of amphetamine could result from a metabolic formation by methylation of amphetamine although in samples with an (R)/(S) ratio for methamphetamine < 1 an additional (previous) (S)-methamphetamine consumption seems likely. Our data suggest that even amphetamine concentrations exceeding methamphetamine concentrations in urine can be caused by the biotransformation of methamphetamine to amphetamine as long as no (R)-amphetamine is detected. However, without chiral information, such findings might be (falsely) assumed as a co-consumption of both substances. Cathinone enantiomers detected in urine samples with high amphetamine concentrations can be interpreted as metabolites of amphetamine. In addition, the results of the self-administration study revealed that both cathinone enantiomers are minor metabolites of (1S,2S)-pseudoephedrine, which is the active ingredient of various medicines used for cold. The enantioselective analysis is a powerful tool to avoid the misinterpretation of ATS findings in urine samples.

Correlation study between the pharmacokinetics of seven main active ingredients of Mahuang decoction and its pharmacodynamics in asthmatic rats.

The aim of this study was to investigate the pharmacokinetics and pharmacodynamics of seven main active components of Mahuang decoction (MHD) and its time-concentration-effect relationship. The asthmatic rat model was established by the method of ovalbumin (OVA) sensttization. The plasma concentrations of ephedrine, pseudoephedrine, methylephedrine, amygdalin, liquiritin, cinnamic acid, glycyrrhizic acid in asthmatic model rat were investigated by a selective and rapid HPLC/MS-MS method. Simultaneously, the asthma-involved cytokines including leukotrienes B4 (LTB4), thromboxane B2 (TXB2), 6-Keto-Prostaglandin F1α (6-K-PGF1α) and histamine (HIS) levels in rat plasma were determined by using ELISA. A mathematics method was applied to assess the trend of percentage rate of change among different time intervals of the seven components. The sigmoid E max function was used to establish the PK-PD modeling of MHD. The results indicated that MHD could control or ameliorate asthma. There was a hysteresis between the peaked drug concentration and maximum therapeutic effect of MHD. The PK-PD curves of MHD showed clockwise or counter-clockwise hysteresis loop. In addition, amygdalin might exert a more significant influence on regulating cytokines levels in asthmatic rats among the seven components of MHD.

Identification and characterization of chemically masked derivatives of pseudoephedrine, ephedrine, methamphetamine, and MDMA.

The emergence of chemically masked illicit drugs represents a challenge to global initiatives that are working to prevent their manufacture and distribution. Targeted analytical techniques currently used by law enforcement to identify unknown materials rely on spectroscopic and spectrophotometric databases that do not currently include some of these compounds, making their identification challenging. This study aimed to update compound spectral libraries to aid in the rapid detection and identification of these masked drugs, as well as to provide insight into their synthetic procedures. Five commonly employed protecting groups, acetyl, p-tosyl, methoxycarbonyl, Fmoc, and t-Boc, were appended to pseudoephedrine, ephedrine, methamphetamine, and MDMA. Characterization was carried out using NMR, GC-MS, FTIR, high-resolution LC-MS/MS, and common screening color tests. Some of the methoxycarbonyl and t-Boc derivatives and all of the Fmoc derivatives showed partial or full thermal degradation or rearrangement during GC-MS analysis, while LC-MS/MS analysis did not always show characteristic fragmentation that would allow unambiguous assignment of the structure. Restricted rotation in some of the derivatives meant that NMR assignments could only be made using NMR spectra acquired at elevated temperature. Therefore, GC-MS and LC-MS/MS analyses serve complementary roles for these derivatives, with NMR providing confirmation of structure for the pure materials if necessary.

Reliable quantification of myocardial sympathetic innervation and regional denervation using [11C]meta-hydroxyephedrine PET.

PURPOSE: Cardiac sympathetic nervous system (SNS) dysfunction is associated with poor prognosis in chronic heart failure patients. This study characterized the reproducibility and repeatability of [11C]meta-hydroxyephedrine (HED) positron emission tomography (PET) quantification of cardiac SNS innervation, regional denervation, and myocardial blood flow (MBF). METHODS: Dynamic HED PET-CT scans were performed 47 ± 22 days apart in 20 patients with stable heart failure and reduced ejection fraction. Three observers, blinded to clinical data, used FlowQuant® to evaluate the test-retest repeatability and inter- and intra-observer reproducibility of HED tracer uptake and clearance rates to measure global (LV-mean) retention index (RI), volume of distribution (VT), and MBF. Values were also compared with and without regional partial-volume correction. Regional denervation was quantified as %LV defect size of values < 75% of the LV-maximum. Test-retest repeatability and observer reproducibility were evaluated using intra-class-correlation (ICC) and Bland-Altman coefficient of repeatability (NPC). RESULTS: Intra- and inter-observer correlations of both VT and RI were excellent (ICC = 0.93-0.99). Observer reproducibility (NPC = 3-13%) was lower than test-retest repeatability (NPC = 12-61%). Both regional (%LV defect size) and global (LV-mean) measures of sympathetic innervation were more repeatable using the simple RI model compared to VT (NPC = 12% vs. 19% and 30% vs. 54%). Using either model, quantification of regional denervation (defect size) was consistently more reliable than the global LV-mean values of RI or VT. Regional partial-volume correction degraded repeatability of both the global and regional VT measures by 2-12%. Test-retest repeatability of MBF estimation was relatively poor (NPC = 30-61%) compared with the RI. CONCLUSIONS: Quantitative measures of global and regional SNS innervation were most repeatable using the simple RI method of analysis compared with the more complex VT. Observer variability was significantly lower than the test-retest repeatability using a highly automated analysis program. These results support the use of the simple RI method for reliable analysis of HED PET images in clinical research studies for future evaluation of new therapies and for risk stratification in patients with heart failure.

Quantification of myocardial blood flow with 11C-hydroxyephedrine dynamic PET: comparison with 15O-H2O PET.

BACKGROUND: 11C-hydroxyephedrine (HED) PET has been used to evaluate the myocardial sympathetic nervous system (SNS). Here we sought to establish a simultaneous approach for quantifying both myocardial blood flow (MBF) and the SNS from a single HED PET scan. METHODS: Ten controls and 13 patients with suspected cardiac disease were enrolled. The inflow rate of 11C-HED (K1) was obtained using a one-tissue-compartment model. We compared this rate with the MBF derived from 15O-H2O PET. In the controls, the relationship between K1 from 11C-HED PET and the MBF from 15O-H2O PET was linked by the Renkin-Crone model. RESULTS: The relationship between K1 from 11C-HED PET and the MBF from 15O-H2O PET from the controls' data was approximated as follows: K1  =  (1 - 0.891 * exp(- 0.146/MBF)) * MBF. In the validation set, the correlation coefficient demonstrated a significantly high relationship for both the whole left ventricle (r = 0.95, P < 0.001) and three coronary territories (left anterior descending artery: r = 0.96, left circumflex artery: r = 0.81, right coronary artery: r =  0.86; P < 0.001, respectively). CONCLUSION: 11C-HED can simultaneously estimate MBF and sympathetic nervous function without requiring an additional MBF scan for assessing mismatch areas between MBF and SNS.

Nuclear Imaging of the Cardiac Sympathetic Nervous System: A Disease-Specific Interpretation in Heart Failure.

Abnormalities in the cardiac sympathetic nervous system have been documented in various heart diseases and have been directly implicated in their pathogenesis and disease progression. Noninvasive techniques using single-photon-emitting radiotracers for planar scintigraphy and single-photon emission computed tomography, and positron-emitting tracers for positron emissions tomography, have been used to characterize the cardiac sympathetic nervous system with norepinephrine analogs [123I]meta-iodobenzylguanidine for planar and single-photon emission computed tomography imaging and [11C]meta-hydroxyephedrine for positron emissions tomography. Their usefulness in prognostication and risk stratification for cardiac events has been demonstrated. This review bridges basic and clinical research and focuses on applying an understanding of tracer kinetics and neuronal biology, to aid in the interpretation of nuclear imaging of cardiac sympathetic innervation.

Enantioselective determination of cathinones in urine by high pressure in-line SPE-CE.

This work presents a strategy based on the in-line coupling of SPE and CE for the chiral determination of cathinones (R,S-mephedrone, R,S-4-methylephedrine, and R,S- methylenedioxypyrovalerone) in urine samples, using a sample pretreatment based on liquid-liquid extraction. The chiral separation of the compounds is achieved by adding a mixture of 8 mM 2-hydroxypropil ß-CD and 5 mM ß-CD to the BGE, which consists of 70 mM of monosodium phosphate aqueous solution at pH 2.5. Oasis HLB was the selected sorbent for the in-line SPE device, and to reduce analysis time and LODs, several parameters affecting the in-line SPE system were evaluated, such as pressure and time of sample injection and dimensions of the SPE device. The highest preconcentration factors were achieved by using 3 bar of injection pressure for 20 min with an in-line SPE device of 2 mm length and 150 µm of i.d. The developed method was applied to determine the presence of the compounds in spiked urine samples. The LODs obtained were between 3 and 8 ng/mL, and these levels were below the usual concentrations at which these drugs are present in urine from cathinone abusers. Thus, the optimized method has the potential to be applied for toxicological and forensic purposes.

New Approaches in the Management of Sudden Cardiac Death in Patients with Heart Failure-Targeting the Sympathetic Nervous System.

Cardiovascular diseases (CVDs) have been considered the most predominant cause of death and one of the most critical public health issues worldwide. In the past two decades, cardiovascular (CV) mortality has declined in high-income countries owing to preventive measures that resulted in the reduced burden of coronary artery disease (CAD) and heart failure (HF). In spite of these promising results, CVDs are responsible for ~17 million deaths per year globally with ~25% of these attributable to sudden cardiac death (SCD). Pre-clinical data demonstrated that renal denervation (RDN) decreases sympathetic activation as evaluated by decreased renal catecholamine concentrations. RDN is successful in reducing ventricular arrhythmias (VAs) triggering and its outcome was not found inferior to metoprolol in rat myocardial infarction model. Registry clinical data also suggest an advantageous effect of RDN to prevent VAs in HF patients and electrical storm. An in-depth investigation of how RDN, a minimally invasive and safe method, reduces the burden of HF is urgently needed. Myocardial systolic dysfunction is correlated to neuro-hormonal overactivity as a compensatory mechanism to keep cardiac output in the face of declining cardiac function. Sympathetic nervous system (SNS) overactivity is supported by a rise in plasma noradrenaline (NA) and adrenaline levels, raised central sympathetic outflow, and increased organ-specific spillover of NA into plasma. Cardiac NA spillover in untreated HF individuals can reach ~50-fold higher levels compared to those of healthy individuals under maximal exercise conditions. Increased sympathetic outflow to the renal vascular bed can contribute to the anomalies of renal function commonly associated with HF and feed into a vicious cycle of elevated BP, the progression of renal disease and worsening HF. Increased sympathetic activity, amongst other factors, contribute to the progress of cardiac arrhythmias, which can lead to SCD due to sustained ventricular tachycardia. Targeted therapies to avoid these detrimental consequences comprise antiarrhythmic drugs, surgical resection, endocardial catheter ablation and use of the implantable electronic cardiac devices. Analogous NA agents have been reported for single photon-emission-computed-tomography (SPECT) scans usage, specially the 123I-metaiodobenzylguanidine (123I-MIBG). Currently, HF prognosis assessment has been improved by this tool. Nevertheless, this radiotracer is costly, which makes the use of this diagnostic method limited. Comparatively, positron-emission-tomography (PET) overshadows SPECT imaging, because of its increased spatial definition and broader reckonable methodologies. Numerous ANS radiotracers have been created for cardiac PET imaging. However, so far, [11C]-meta-hydroxyephedrine (HED) has been the most significant PET radiotracer used in the clinical scenario. Growing data has shown the usefulness of [11C]-HED in important clinical situations, such as predicting lethal arrhythmias, SCD, and all-cause of mortality in reduced ejection fraction HF patients. In this article, we discussed the role and relevance of novel tools targeting the SNS, such as the [11C]-HED PET cardiac imaging and RDN to manage patients under of SCD risk.

Multivariate approaches for the development of quality control in-situ fiber optics dissolution methods for fixed-dose combination tablets.

The purpose of this research was to develop a fiber optic (FO) dissolution method for quantification of multiple actives in combination pharmaceutical tablets. FO dissolution allows direct API quantification in the vessel, obviating the need for error-prone facets of traditional dissolution methods. However, FO dissolution is potentially challenged by overlapping UV spectra, matrix effects, UV-active excipients, API interactions with excipients and media, and undissolved components attenuating the UV signal. These obstacles might render FO dissolution method development more complex than LC-end dissolution. The case study in this manuscript has the added complexity of a triple combination product (Midol), where acetaminophen, caffeine, and pyrilamine maleate exhibit similar release kinetics, share largely overlapping UV spectra and span an order of magnitude difference in concentration. Single-wavelength quantification required unique features for the actives of interest, which were not available for the formulation of interest without preprocessing. The methods employed for the quantification of actives were a partial least squares multivariate calibration and a peak area calibration, both using prepared mixtures as reference data. The selected combination tablet demonstrated collinear API release; therefore, individual quantification required a design of experiments for mixture design. The advantages of FO dissolution will be discussed in the context of the formulation under investigation. Additionally, some general guidelines will be suggested for the development of other FO methods.

Early therapeutic effects of adaptive servo-ventilation on cardiac sympathetic nervous function in patients with heart failure evaluated using a combination of 11C-HED PET and 123I-MIBG SPECT.

RATIONALE: Adaptive servo-ventilation (ASV), a novel respiratory support therapy for sleep disorders, may improve cardiac function in heart failure (HF). However, the reasons that ASV improves cardiac function have not been fully studied especially in sympathetic nervous function (SNF). The purpose of the present study was to investigate the effects of ASV therapy on cardiac SNF in patients with HF. METHODS: We evaluated ASV therapeutic effects before and 6 months after ASV therapy in 9 HF patients [57.3 ± 17.3 years old, left ventricular ejection fraction (LVEF) 36.1 ± 16.7%]. We performed echocardiography, polysomnography, biomarkers, 11C-hydroxyephedrine (HED) PET as a presynaptic function marker and planar 123I-metaiodobenzylguanidine (MIBG) to evaluate washout rate. RESULTS: ASV therapy reduced apnea-hypopnea index (AHI) and improved plasma brain natriuretic peptide (BNP) concentration. In 123I-MIBG imaging, the early heart/mediastinum (H/M) ratio increased after ASV therapy (2.19 ± 0.58 to 2.40 ± 0.67; P = 0.045). Washout rate did not change (23.8 ± 7.3% to 23.8 ± 8.8%; P = 0.122). Global 11C-HED retention index (RI) improved from 0.068 ± 0.033/s to 0.075 ± 0.034/s (P = 0.029). CONCLUSIONS: ASV reduced AHI and improved BNP. ASV might initially improve presynaptic cardiac sympathetic nervous function in HF patients after 6 months of treatment.