In vitro and in vivo characterization of an interleukin‐15 antagonist peptide by metabolic stability, 99mTc‐labeling,and biological activity assays

Interleukin (IL)–15 is an inflammatory cytokine that constitutes a validated therapeutic target in some immunopathologies, including rheumatoid arthritis (RA). Previously, we identified an IL‐15 antagonist peptide named [K6T]P8, with potential therapeutic application in RA. In the current work, the metabolic stability of this peptide in synovial fluids from RA patients was studied. Moreover, [K6T]P8 peptide was labeled with ^99mTc to investigate its stability in human plasma and its biodistribution pattern in healthy rats. The biological activity of [K6T]P8 peptide and its dimer was evaluated in CTLL‐2 cells, using 3 different additives to improve the solubility of these peptides. The half‐life of [K6T]P8 in human synovial fluid was 5.88 ± 1.73 minutes, and the major chemical modifications included peptide dimerization, cysteinylation, and methionine oxidation. Radiolabeling of [K6T]P8 with ^99mTc showed a yield of approximately 99.8%. The ^99mTc‐labeled peptide was stable in a 30‐fold molar excess of cysteine and in human plasma, displaying a low affinity to plasma proteins. Preliminary biodistribution studies in healthy Wistar rats suggested a slow elimination of the peptide through the renal and hepatic pathways. Although citric acid, sucrose, and Tween 80 enhanced the solubility of [K6T]P8 peptide and its dimer, only the sucrose did not interfere with the in vitro proliferation assay used to assess their biological activity. The results here presented, reinforce nonclinical characterization of the [K6T]P8 peptide, a potential agent for the treatment of RA and other diseases associated with IL‐15 overexpression.     

Baseline serum levels of cardiac biomarkers in patients with stable coronary artery disease

Stable coronary artery disease (CAD) can cause repetitive reversible myocardial ischaemia, and it seems to be possible that reversibly injured myocardium releases small amounts of soluble cytoplasmic proteins. Hence, the aim was to evaluate the effect of stable CAD on baseline serum levels of cardiac biomarkers. We studied 68 consecutive outpatients referred for gated myocardial perfusion imaging. Before a treadmill exercise test, blood samples for measurement of creatine kinase (CK), CK-myocardial band (CK-MB) mass, myoglobin, aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) were collected. Normal perfusion patterns were detected in 29 (43%) patients (group 1) and perfusion defects were detected in 39 (57%) patients (group 2). Baseline serum levels of biomarkers except CK were significantly higher in group 2 (p=0.001). Stable CAD increases baseline levels of CK-MB mass, myoglobin, AST and LDH in the serum and this increase is related to the extent and severity of the perfusion defect and to some extent the ejection fraction of the left ventricle.     

Comparison of Amberchrom-CG161C and Dowex99 as the adsorbent of a four-zone simulated moving bed process for removal of acetic acid from biomass hydrolyzate

One of the important steps in the application of biomass to producing sugars, which can be converted into bio-ethanol and other valuable chemicals by fermentation, is to hydrolyze the biomass components by sulfuric acid. It was reported that such a hydrolysis entailed the generation of acetic acid, which has been recognized as a key impurity to be surely removed from the biomass hydrolyzate for ensuring high fermentability of the hydrolyzed sugars. Regarding such a removal task, there has been a previous application of a simulated moving bed (SMB) process based on the Dowex99 adsorbent, whose performance, however, was limited by low selectivity between acetic acid and sugars. To overcome such a limitation, another adsorbent alternative to Dowex99 was searched in this study. It was found that Amberchrom-CG161C allowed higher selectivity between acetic acid and sugars than Dowex99. To investigate the relative superiority of Amberchrom-CG161C over Dowex99 as the adsorbent of an SMB process for removing acetic acid from the biomass hydrolyzate, the two SMB processes based on Amberchrom-CG161C and Dowex99 were optimized using the SMB optimization tool based on standing wave design (SWD) method. The optimization results revealed that the Amberchrom-CG161C SMB outperformed the Dowex99 SMB by a wide margin.     

Measurement of Extracellular Ion Fluxes Using the Ion-selective Self-referencing Microelectrode Technique

Cells from animals, plants and single cells are enclosed by a barrier called the cell membrane that separates the cytoplasm from the outside. Cell layers such as epithelia also form a barrier that separates the inside from the outside or different compartments of multicellular organisms. A key feature of these barriers is the differential distribution of ions across cell membranes or cell layers. Two properties allow this distribution: 1) membranes and epithelia display selective permeability to specific ions; 2) ions are transported through pumps across cell membranes and cell layers. These properties play crucial roles in maintaining tissue physiology and act as signaling cues after damage, during repair, or under pathological condition. The ion-selective self-referencing microelectrode allows measurements of specific fluxes of ions such as calcium, potassium or sodium at single cell and tissue levels. The microelectrode contains an ionophore cocktail which is selectively permeable to a specific ion. The internal filling solution contains a set concentration of the ion of interest. The electric potential of the microelectrode is determined by the outside concentration of the ion. As the ion concentration varies, the potential of the microelectrode changes as a function of the log of the ion activity. When moved back and forth near a source or sink of the ion (i.e. in a concentration gradient due to ion flux) the microelectrode potential fluctuates at an amplitude proportional to the ion flux/gradient. The amplifier amplifies the microelectrode signal and the output is recorded on computer. The ion flux can then be calculated by Fick’s law of diffusion using the electrode potential fluctuation, the excursion of microelectrode, and other parameters such as the specific ion mobility. In this paper, we describe in detail the methodology to measure extracellular ion fluxes using the ion-selective self-referencing microelectrode and present some representative results.     

2012–2013年中国禾柄锈菌小麦专化型小种动态及新毒力谱分析

监测具有潜在威胁的小麦秆锈病病原菌小种动态并分析其毒力谱变化,是培育抗病品种不可或缺的基础工作。在小麦秆锈病鲜有发生的情况下,于2012–2013年获得小麦田间秆锈病标样11份和经有性生殖过程的禾柄锈菌小麦专化型菌样22份。上述菌样经过分离、纯化,得到了53个单孢子堆菌株。利用国内最新采用的禾柄锈菌小麦专化型小种与毒力鉴别寄主体系进行分析,鉴定出13个生理小种,其中34C3RTGQM和34Oro II-MRGQM为优势小种,出现频率均为13.2%,首次发现了对Sr5+Sr11具有联合毒力的6个新小种,其出现频率处在1.9%–13.2%范围内。同时测定出Sr9e、Sr26、Sr31、Sr33、Sr37、Sr38、Sr47和Sr Tt3等8个抗秆锈病单基因对全部供试菌株表现抗病,余下40个单基因系则分别表现对1个以上至全部菌株感病。结论:(1)首次报道了6个对Sr5+Sr11具有危险性的联合毒力谱的新小种类型,这类毒力类型应当被密切关注;(2)明确了当前完全有效的8个抗秆锈病基因和其他部分有效的抗病基因;(3)初步说明了有性循环菌株与无性循环菌株在毒力结构上存在差异。     

La scintigraphie de perfusion hépatique dans la prise en charge des patients traités par chimiothérapie intra-artérielle hépatique

Nearly 50 % of patients with colorectal cancer (CRC) develop liver metastases (LM) during their disease. Only 10 % of these patients are candidates for an initial surgical resection. Compared to systemic chemotherapy alone, intra-arterial hepatic chemotherapy showed a benefit in overall survival in patients with unresectable LM. This treatment requires surgical or endovascular introduction of an intra-arterial hepatic catheter (IAHC). A precise vascular assessment is necessary due to the frequency of anatomic variations of hepatic arterial vasculature. Complications of intra-arterial hepatic chemotherapy are related to both IAHC and chemotherapy. ^99mTc-MAA hepatic perfusion scanning plays a key role before treatment initiation and during follow-up. Moreover, intra-hepatic distribution of tracer can be analysed and objectify a possible extra-hepatic spread that may lead to increased toxicity and/or less effective treatment. The different protocols, the place of ^99mTc-MAA scanning compared with other imaging techniques, or frequency of checks are still debated. A literature review is presented, illustrated with some cases of normal and pathological liver perfusion scans from the department of Nuclear Medicine, Val d’Aurelle Regional Cancer Center, Montpellier.     

Synthesis and biological evaluation of technetium-99m labeled galactose derivatives as potential asialoglycoprotein receptor probes in a hepatic fibrosis mouse model

Two galactose derivatives, a monovalent ^99mTc-MAMA-MGal galactoside and a divalent ^99mTc-MAMA-DGal galactoside, were synthesized and radiolabeled in high radiochemical purity (>98%). Dynamic microSPECT imaging and biodistribution study of two traces in normal and liver fibrosis mice showed that the ^99mTc-MAMA-DGal revealed higher specific binding to asialoglycoprotein receptors in liver and then rapidly excreted via both hepatobiliary system and renal clearance. The results suggest that ^99mTc-MAMA-DGal may be used as SPECT probes for noninvasive evaluation of asialoglycoprotein receptor-related liver dysfunction.     

3D image-based dosimetry for Yttrium-90 radioembolization of hepatocellular carcinoma: Impact of imaging method on absorbed dose estimates

BackgroundTo improve therapy outcome of Yttrium-90 selective internal radiation therapy (⁹⁰Y SIRT), patient-specific post-therapeutic dosimetry is required. For this purpose, various dosimetric approaches based on different available imaging data have been reported. The aim of this work was to compare post-therapeutic 3D absorbed dose images using Technetium-99m (^99mTc) MAA SPECT/CT, Yttrium-90 (⁹⁰Y) bremsstrahlung (BRS) SPECT/CT, and ⁹⁰Y PET/CT.MethodsTen SIRTs of nine patients with unresectable hepatocellular carcinoma (HCC) were investigated. The ^99mTc SPECT/CT data, obtained from ^99mTc-MAA-based treatment simulation prior to ⁹⁰Y SIRT, were scaled with the administered ⁹⁰Y therapy activity. 3D absorbed dose images were generated by dose kernel convolution with scaled ^99mTc/⁹⁰Y SPECT/CT, ⁹⁰Y BRS SPECT/CT, and ⁹⁰Y PET/CT data of each patient. Absorbed dose estimates in tumor and healthy liver tissue obtained using the two SPECT/CT methods were compared against ⁹⁰Y PET/CT.ResultsThe percentage deviation of tumor absorbed dose estimates from ⁹⁰Y PET/CT values was on average −2 ± 18% for scaled ^99mTc/⁹⁰Y SPECT/CT, whereas estimates from ⁹⁰Y BRS SPECT/CT differed on average by −50 ± 13%. For healthy liver absorbed dose estimates, all three imaging methods revealed comparable values.ConclusionThe quantification capabilities of the imaging data influence ⁹⁰Y SIRT tumor dosimetry, while healthy liver absorbed dose values were comparable for all investigated imaging data. When no ⁹⁰Y PET/CT image data are available, the proposed scaled ^99mTc/⁹⁰Y SPECT/CT dosimetry method was found to be more appropriate for HCC tumor dosimetry than ⁹⁰Y BRS SPECT/CT based dosimetry.