The “lamellated” skull in β-thalassaemia

The skull in homozygous -thalassaemia may present several abnormalities, such as osteopenia, widening of the diploic space, and a hairon-end appearance. In some cases it presents also a particular stratified appearance caused by a variable number of osseous lamellae, parallel with the inner table. This lamellated skull was observed in 16 out of 150 patients affected by the disease (10.6%). Possible mechanisms are discussed. The lamellar osseous changes could be due to repeated periosteal osteoblastic reactions to the sinusoidal neovascularization associated with marrow hyperplasia in poorly transfused patients.     

Measurement of β-tryptase in postmortem serum in cardiac deaths

Mast cells are well known for their role in hypersensitivity reactions. However, there is increasing evidence that they might also participate in both developing and weakening atherosclerotic plaques, potentially causing plaque instability. Some clinical studies have therefore postulated the existence of relationships between blood β-tryptase levels and acute coronary syndromes. In this study, we investigated postmortem serum β-tryptase levels in a series of 90 autopsy cases with various degrees of coronary atherosclerosis that had undergone medico-legal investigations. β-tryptase concentrations in these cases were compared to levels observed in 6 fatal anaphylaxis cases following contrast material administration. Postmortem serum β-tryptase concentrations in the anaphylactic deaths ranged from 146 to 979 ng/ml. In 9 out of 90 cases of cardiac deaths, β-tryptase levels were higher than clinical reference values of 11.4 ng/ml and ranged from 21 to 65 ng/ml. These results indicate that increased postmortem serum β-tryptase levels can be observed, though not systematically, in cardiac deaths with varying degrees of coronary atherosclerosis disease, thereby suggesting that mast cell activation in this disease cannot be ascertained by postmortem serum β-tryptase measurements.     

Measurement by spectrometry of hard β-emitters in environmental samples

A spectrometric method is described for measuring, in suitable environmental samples, picocurie levels of nuclides emitting hard β-particles (end-point energies ≳1.5 MeV). The detection system is inexpensive, being based upon a plastic scintillator with a thin gas-flow proportional counter as a coincidence trigger. Measured spectra are fitted using a computer programme by library spectra based upon calculation. Spectra of the following nuclides relevant to the fitting procedure are published here: ⁹⁰Y, ¹⁰⁶Rh, ¹⁴⁴Pr, ^234mPa, ²¹⁴Bi, ²²⁸Ac, ²¹²Bi, ²⁰⁸Tl. Studies of system sensitivity are described. Measurements of ⁹⁰Sr⁹⁰Y were made in evaporated rainwater samples, which were then analyzed using a radiochemical method. In general, good agreement was obtained.     

Growth plate injury of the long bones in treated β-thalassemia

In 12 patients affected by thalassemia major who received an intensive transfusion regimen combined with continuous iron chelation therapy (desferrioxamine 50–80 mg/kg daily), radiologic abnormalities of the long bones were observed similar to those observed in rickets and scurvy. These abnormalities were associated with a growth retardation. The pathogenesis of these lesions is uncertain, but probably the toxic effect of desferrioxamine plays an important role in their development. A relative deficiency of vitamins D and/or C cannot be entirely excluded.     

Benefits of β-hydroxy-β-methylbutyrate supplementation in trained and untrained individuals

ABSTRACT

β-Hydroxy-β-Methylbutyrate (HMB) is a metabolite of the branched-chain amino acid leucine and its ketoacid α-ketoisocaproate. HMB has been widely used as an ergogenic supplement to increase muscle strength, muscle hypertrophy and enhance recovery. The physiological mechanisms that underlie these benefits are related to HMB’s ability to stimulate muscle protein synthesis and minimize muscle breakdown. Although evidence supporting the benefits of HMB supplementation is not conclusive, many of these studies have suffered from methodological flaws including different formulations, supplement duration and population studied. HMB in its free acid formulation is suggestive of having a greater potential for efficacy in both trained and untrained populations than its calcium-salt form. However, the evidence regarding HMB’s role in limiting muscle degradation and increasing muscle protein synthesis has created an exciting interest in examining its efficacy among untrained individuals. Recent investigations examining intense training have demonstrated efficacy in maintaining muscle mass and attenuating the inflammatory response.     

Pharmacologic characterization in vitro and in vivo of iodine 123-labeled derivatives of the β-adrenoceptor antagonist CGP 12177, designed for the imaging of cardiac β-receptors

Background

Potential new radioligands for the noninvasive imaging of cardiac β-adrenoceptors with single-photon emission computed tomography were investigated.

Methods and Results

Two iodinated derivatives of CGP12177 para (S-CYBL2B) and ortho (CYBL2A) substituted CGP12177 and an iodinated form of nadolol (CYBL1) were synthesized. Their affinity was tested in vitro (left ventricular homogenates). The biodistribution of [¹²³I]S-CYBL2B was evaluated in rabbits. Specific binding was assessed by pretreatment of the animals with 0.1 μmol propranolol. The inhibition constant values (in nanomolars, means±SEM; n=3 to 5) were determined at 1.17±0.42, 28800±9260, 11.1±2.1, 53.0±19.9, and 1790±700 for CGP12177, CYBL2A, S-CYBL2B, nadolol, and CYBL1. Myocardial uptake of [¹²³I]S-CYBL2B was not inhibited by pretreatment of the animals with propranolol, but uptake by lung tissue could be blocked by propranolol (0.63%±0.09% vs 0.33%±0.02% % injected dose/g×kg; p<0.05). In isolated right atria, preincubation with S-CYBL2B induced a parallel rightward shift of the concentration-response curve with isoprenaline.

Conclusions

S-CYBL2B shows high affinity for cardiac β-adrenoceptors, but binding proved nonspecific in vivo, whereas binding in lung tissue was specific. These results suggest that S-CYBL2B is probably not a suitable radioligand for receptor imaging.     

Simultaneous in vivo magnetic resonance imaging and radioactive measurements with the β-MicroProbe

Purpose Multimodal instrumentation is a new technical approach allowing simultaneous and complementary in vivo recordings of complementary biological parameters. To elucidate further the physiopathological mechanisms in intact small animal models, especially for brain studies, a challenging issue is the actual coupling of magnetic resonance imaging (MRI) techniques with positron emission tomography (PET): it has been shown that running the technology for radioactive imaging in a magnet alters the spatiotemporal performance of both modalities. Thus, we propose an alternative coupling of techniques that uses the β-MicroProbe instead of PET for local measurements of radioactivity coupled with MRI. Methods We simultaneously recorded local radioactivity due to [¹⁸F]MPPF (a 5-HT_1A receptor PET radiotracer) binding in the hippocampus with the β-MicroProbe and carried out anatomical MRI in the same anaesthetised rat. Results The comparison of [¹⁸F]MPPF kinetics obtained from animals in a magnet with kinetics from a control group outside the magnet allowed us to determine the stability of tracer biokinetic measurements over time in the magnet. We were thus able to show that the β-MicroProbe reliably measures radioactivity in rat brains under an intense magnetic field of 7 Tesla. Conclusion The biological validation of a β-MicroProbe/MRI dual system reported here opens up a wide range of future multimodal approaches for functional and pharmacological measurements by the probe combined with various magnetic resonance technologies, including anatomical MRI, functional MRI and MR spectroscopy.     

The use of β-TCP in the surgical treatment of tibial plateau fractures

The objective of this study was to evaluate the outcome of using β-TCP in the treatment of depression tibial plateau fractures. A total of 124 patients with depression tibial fractures were included in this study and followed for a minimum of 12 months. All the cases were treated with open reduction and internal fixation, and grafted with β-TCP ceramic. The clinical and radiological outcomes were assessed using Hospital for Special Surgery (HSS) score of knee and Rasmussen score during the follow-up. No obvious redisplacement was found at the follow-up assessment. Most of the patients had excellent HSS score and Rasmussen clinical score. Bone healing was noted in all fractures and Schatzker II-type fractures had the best functional outcome. The results suggested that using β-TCP combined with open reduction and rigid internal fixation was an effective treatment for depression fractures of the tibial plateau.     

Suppression of β-particle events using a capillary tube in liquid scintillation α spectrometry

A method to decrease photons generated by β particles by using a capillary tube in liquid scintillation α spectrometry is presented. Liquid scintillation counting of ²⁴¹Am and ¹⁵²Eu was performed with 200, 300, and 500 μm inner diameter (i.d.) PFA tubes as the detection cell. It was observed that the β component in the energy spectrum is located at the lower-energy region with a decreasing i.d. of the PFA tubes, and the α peak of ²⁴¹Am was separated from the β component.     

Expression of β-defensin-4 in “an in vivo and ex vivo model” of human osteoarthritic knee meniscus

Purpose  

To investigate, for the first time, the expression of β-defensins-4, by immunohistochemistry and western blotting, in OA meniscus versus control meniscus, thus providing new insights into the physiological processes of meniscus repairing.     

Reduced CGP12177 binding to cardiac β-adrenoceptors in hyperglycemic high-fat-diet-fed, streptozotocin-induced diabetic rats

Introduction

Abnormal sympathetic nervous system and β-adrenoceptor (β-AR) signaling is associated with diabetes. [³H]CGP12177 is a nonselective β-AR antagonist that can be labeled with carbon-11 for positron emission tomography. The aim of this study was to examine the suitability of this tracer for evaluation of altered β-AR expression in diabetic rat hearts.

Methods

Ex vivo biodistribution with [³H]CGP12177 was carried out in normal Sprague–Dawley rats for evaluation of specific binding and response to continuous β-AR stimulation by isoproterenol. In a separate group, high-fat-diet feeding imparted insulin resistance and a single intraperitoneal injection of streptozotocin (STZ) or vehicle evoked hyperglycemia (blood glucose >11 mM). [³H]CGP12177 biodistribution was assessed at 2 and 8 weeks post-STZ to measure β-AR binding in heart, 30 min following tracer injection. Western blotting of β-AR subtypes was completed in parallel.

Results

Infusion of isoproterenol over 14 days did not affect cardiac binding of [³H]CGP12177. Approximately half of rats treated with STZ exhibited sustained hyperglycemia and progressive hypoinsulinemia. Myocardial [³H]CGP12177 specific binding was unchanged at 2 weeks post-STZ but significantly reduced by 30%–40% at 8 weeks in hyperglycemic but not euglycemic STZ-treated rats compared with vehicle-treated controls. Western blots supported a significant decrease in β₁-AR in hyperglycemic rats.

Conclusions

Reduced cardiac [³H]CGP12177 specific binding in the presence of sustained hyperglycemia corresponds to a decrease in relative β₁-AR expression. These data indirectly support the use of [¹¹C]CGP12177 for assessment of cardiac dysfunction in diabetes.     

Simple analysis of α-amanitin and β-amanitin in human plasma by liquid chromatography-mass spectrometry

A number of reports are available in the literature that describe liquid chromatography-mass spectrometry (LC-MS) and LC-tandem mass spectrometry (LC-MS-MS) analysis of amanitins, very toxic mushroom toxins, in biological samples. However, the extractive pretreatment methods and LC separation column materials vary remarkably according to the different reports. This communication presents a very simple and suffi ciently sensitive method for LC-MS analysis of amanitins. A plasma sample was diluted with distilled water and buffer solution, and applied to a Discovery DSC 18 column (500 mg packing material), followed by washing with distilled water and elution with methanol. The extract, after evaporation and reconstitution in mobile phase solution, was subjected to LC-MS analysis with a conventional octadecyl LC separation column. The selected ion monitoring of α-amanitin and β-amanitin at m/z 919–921 and m/z 920–922, respectively, gave symmetrical peaks and good separation of both amanitin peaks. Using an external calibration method, linearity, detection limits, recovery rates, and precision were tested; they were all satisfactory. To our knowledge, the present method gives the simplest LC-MS analysis for amanitins among those so far reported. We recommend the method for use in actual forensic and clinical toxicological analysis of amanitins in biological samples.     

18F-Labeled benzylideneaniline derivatives as new ligands for β-amyloid plaque imaging in Alzheimer's disease

IntroductionNoninvasive early detection of β-amyloid (Aβ) plaques might be useful for the treatment of patients with Alzheimer's disease (AD). We herein describe the synthesis of ¹⁸F-labeled benzylideneaniline derivatives using a novel labeling approach for imaging Aβ plaques in AD patients.MethodsBenzylidenaniline derivatives were synthesized by reacting fluorobenzaldehyde and corresponding aniline derivatives. Fluorobenzaldehyde was labeled with ¹⁸F by incubating [¹⁸F]fluoride with N,N,N-trimethylbenzaldehyde in the presence of tetrabutylammonium bicarbonate. In vitro binding assay, stability test and biodistribution study were performed.ResultsThese compounds were stable at alkaline pH (pH >9); however, they were hydrolyzed rapidly at physiological pH (pH ～7.4). The K_i values of amine-containing benzylideneaniline derivatives for Aβ_1–40 and Aβ_1–42 aggregates were 26–78 nM. These ¹⁸F-labeled benzylideneaniline derivatives showed high brain uptake and rapid clearance after intravenous administration in normal mice (1.8–3.1%ID/g at 2 min and 0.1–1.2%ID/g at 30 min). The low level of bone activity at 30 min indicated that these ¹⁸F-labeled benzylideneanilines are not prone to defluorination. Furthermore, the compounds have suitable lipophilicity — a property required to penetrate the blood–brain barrier.ConclusionThese results showed that the instability of these compounds could cause a higher early phase/late phase ratio due to rapid clearance in the normal brain. The findings from this study suggest that these ¹⁸F-labeled benzylideneaniline derivatives are feasible for the imaging of Aβ plaques.     

MALDI-TOF mass spectrometric analysis of α-amanitin, β-amanitin, and phalloidin in urine

A rapid and sensitive method was developed for analysis of α-amanitin, β-amanitin, and phalloidin by matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). In this method, α-cyano-4-hydroxy cinnamic acid was used as the matrix to assist the ionization of toxins. The identification of α-amanitin, β-amanitin, and phalloidin was achieved through their sodium adducts [M+Na]⁺ at m/z = 941, 942, and 811, and quantification of the three toxins was also achieved using microcystin RR at m/z = 1038 as internal standard. For all toxins, the limit of detection was 5 ng/ml, and all calibration curves were linear in the range of 10–500 ng/ml using 0.4 ml of urine. The sensitivity for identification was increased about tenfold when the tandem MS (MS–MS) mode was used for detection. Because these quantifications could be achieved in the toxin concentration range of 4–200 ng, the present MALDI-TOF MS method can serve as the most sensitive method so far reported for the analysis of these mushroom toxins. To our knowledge, this study is the first trial to analyze amanitins and phalloidin by MALDI-TOF MS (-MS).     

Dose distribution from β-radiation in heterogeneous media: “Two-group” method of calculation

A new method is suggested for calculating distributions of absorbed energy from β-radiation in heterogeneous combinations of various media with atomic number Z in the range 7 ≲ Z ≲ 50. The method can be applied only to spectra of a certain, artificial, “quasi-equilibrium” shape. Therefore, the spectrum of β-radiation of the source in question should first be presented as the superposition of several partial quasi-equilibrium spectra. The dose distribution from a point source with this partial spectrum is then considered as the sum of two components of the dose: “directional” and “diffusion”. The first component is described by the function of the point source (FPS) of the simplest form, and the second one by solutions of the diffusion equation in each medium under certain boundary conditions. Parameters appearing in the FPS and solutions of the diffusion equation are estimated empirically.The paper reports formulae for calculating dose distributions for several of the simplest geometrical configurations for source and absorbers. Dose distributions calculated by the “two-group” method suggested are compared with data obtained in specially performed experiments. The agreement of the results is quite satisfactory.     

Demonstration of pulmonary β2-adrenergic receptor binding in vivo with [18F]fluoroethyl-fenoterol in a guinea pig model

Purpose The new ₂ radioligand (R,R)(S,S) 5-(2-(2-[4-(2-[¹⁸F]fluoroethoxy)phenyl]-1-methylethylamino)-1-hydroxyethyl)-benzene-1,3-diol ([¹⁸F]FE-fenoterol; [¹⁸F]FEFE), a fluoroethylated derivative of racemic fenoterol, was evaluated in vivo and ex vivo using a guinea pig model.Methods Dynamic PET studies over 60 min with [¹⁸F]FEFE were performed in nine Hartley guinea pigs in which a baseline (group 1, n=3), a predose (group 2, n=3; 2 mg/kg fenoterol 5 min prior to injection of [¹⁸F]FEFE) or a displacement study (group 3, n=3; 2 mg/kg fenoterol 5 min post injection of [¹⁸F]FEFE) was conducted.Results In all animal groups, the lungs could be visualised and semi-quantified separately by calculating uptake ratios to non-specific binding in the neck area. Premedication with non-radioactive fenoterol and displacement tests showed significant reduction of lung uptake, by 94% and 76%, respectively.Conclusion These data demonstrate specific binding of the new radioligand to the pulmonary ₂-receptors in accordance with ex vivo measurements. Therefore, [¹⁸F]FEFE seems to be suitable for the in vivo visualisation and quantification of the pulmonary ₂-receptor binding in this animal model.