Time-series analysis of rhenium(I) organometallic covalent binding to a model protein for drug development

Metal-based complexes with their unique chemical properties, including multiple oxidation states, radio-nuclear capabilities and various coordination geometries yield value as potential pharmaceuticals. Understanding the interactions between metals and biological systems will prove key for site-specific coordination of new metal-based lead compounds. This study merges the concepts of target coordination with fragment-based drug methodologies, supported by varying the anomalous scattering of rhenium along with infrared spectroscopy, and has identified rhenium metal sites bound covalently with two amino acid types within the model protein. A time-based series of lysozyme-rhenium-imidazole (HEWL-Re-Imi) crystals was analysed systematically over a span of 38 weeks. The main rhenium covalent coordination is observed at His15, Asp101 and Asp119. Weak (i.e. noncovalent) interactions are observed at other aspartic, asparagine, proline, tyrosine and tryptophan side chains. Detailed bond distance comparisons, including precision estimates, are reported, utilizing the diffraction precision index supplemented with small-molecule data from the Cambridge Structural Database. Key findings include changes in the protein structure induced at the rhenium metal binding site, not observed in similar metal-free structures. The binding sites are typically found along the solvent-channel-accessible protein surface. The three primary covalent metal binding sites are consistent throughout the time series, whereas binding to neighbouring amino acid residues changes through the time series. Co-crystallization was used, consistently yielding crystals four days after setup. After crystal formation, soaking of the compound into the crystal over 38 weeks is continued and explains these structural adjustments. It is the covalent bond stability at the three sites, their proximity to the solvent channel and the movement of residues to accommodate the metal that are important, and may prove useful for future radiopharmaceutical development including target modification.

The Clinical Utility of Gallium-68-DOTATATE Positron Emission Tomography Scanning in Medullary Thyroid Cancer

OBJECTIVE

Somatostatin receptor (SST) functional imaging with positron emission tomography (PET)/computed tomography (CT) has broadened the diagnostic and staging capabilities for medullary thyroid cancer (MTC). Gallium-68 (68Ga)-DOTA-conjugated peptide (Tyr3)-octreotate (DOTATATE) is a radiotracer with a high affinity for type 2 SSTs expressed in several, but not all, MTCs. The utility of 68Ga-DOTATATE PET/CT and 18fluorine-labeled fluoro-2-deoxy-D-glucose (18F-FDG)-PET/CT imaging in predicting MTC prognosis is also unknown.

METHODS

In this single-center retrospective study, 103 of patients with MTC underwent assessment of SST2 and SST5 immunohistochemistry (IHC). A subgroup of 37 patients received 68Ga-DOTATATE PET/CT imaging, and 13 received contemporaneous 18F-FDG-PET/CT imaging. The maximum standardized uptake value (SUV), mean SUV, metabolic tumor volume, and total lesion activity (TLA) were assessed.

RESULTS

Forty-two patients (41%) demonstrated positive expression of SST2, and 45 (44%) had a positive SST5 IHC result. Seventeen patients (17%) expressed both SST2 and SST5. No survival advantage was identified with SST2 or SST5 IHC positivity. No correlation was noted between the maximum SUV, mean SUV, metabolic tumor volume, or TLA and SST2 and/or SST5 expression by IHC. Shorter survival was associated with a TLA of >20 (P = .04). A RET-negative status also appeared to have shorter survival, although this may be because the small numbers did not reach statistical significance (P = .12).

CONCLUSION

Assessment of TLA from 68Ga-DOTATATE PET/CT may predict survival. SST2 IHC was not correlated with 68Ga-DOTATATE avidity. Metastatic disease may be optimally assessed by concurrent 18F-FDG and 68Ga-DOTATATE imaging.

Copper pyrithione and zinc pyrithione induce cytotoxicity and neurotoxicity in neuronal/astrocytic co-cultured cells via oxidative stress

Previous studies on copper pyrithione (CPT) and zinc pyrithione (ZPT) as antifouling agents have mainly focused on marine organisms. Even though CPT and ZPT pose a risk of human exposure, their neurotoxic effects remain to be elucidated. Therefore, in this study, the cytotoxicity and neurotoxicity of CPT and ZPT were evaluated after the exposure of human SH-SY5Y/astrocytic co-cultured cells to them. The results showed that, in a co-culture model, CPT and ZPT induced cytotoxicity in a dose-dependent manner (~ 400 nM). Exposure to CPT and ZPT suppressed all parameters in the neurite outgrowth assays, including neurite length. In particular, exposure led to neurotoxicity at concentrations with low or no cytotoxicity (~ 200 nM). It also downregulated the expression of genes involved in neurodevelopment and maturation and upregulated astrocyte markers. Moreover, CPT and ZPT induced mitochondrial dysfunction and promoted the generation of reactive oxygen species. Notably, N-acetylcysteine treatment showed neuroprotective effects against CPT- and ZPT-mediated toxicity. We concluded that oxidative stress was the major mechanism underlying CPT- and ZPT-induced toxicity in the co-cultured cells.

Metastatic Esophageal Adenocarcinoma Showing 68 Ga-DOTATATE Uptake

ABSTRACT

The role of 68 Ga-DOTATATE PET/CT in the evaluation of neuroendocrine tumors is well defined. Nevertheless, 68 Ga-DOTATATE uptake may be seen in some tumors other than neuroendocrine tumors as a reflection of tumor blood supply and somatostatin receptor expression. Although 68 Ga-DOTATATE uptake has been described in a number of nonneuroendocrine tumors, no case of 68 Ga-DOTATATE uptake in esophagus adenocarcinoma has been reported. We present the case of a 52-year-old man who had a metastatic esophageal adenocarcinoma showing 68 Ga-DOTATATE uptake.

Fine-tuning the cytotoxicity of ruthenium(II) arene compounds to enhance selectivity against breast cancers

Ruthenium-based complexes have been suggested as promising anticancer drugs exhibiting reduced general toxicity compared to platinum-based drugs. In particular, Ru(η6-arene)(PTA)Cl2 (PTA = 1,3,5-triaza-7-phosphaadamantane), or RAPTA, complexes have demonstrated efficacy against breast cancer by suppressing metastasis, tumorigenicity, and inhibiting the replication of the human tumor suppressor gene BRCA1. However, RAPTA compounds have limited cytotoxicity, and therefore comparatively high doses are required. This study explores the activity of a series of RAPTA-like ruthenium(II) arene compounds against MCF-7 and MDA-MB-231 breast cancer cell lines and [Ru(η6-toluene)(PPh3)2Cl]+ was identified as a promising candidate. Notably, [Ru(η6-toluene)(PPh3)2Cl]Cl was found to be remarkably stable and highly cytotoxic, and selective to breast cancer cells. The minor groove of DNA was identified as a relevant target.

Heat shock protein 70 is involved in polaprezinc driven cell protection against Helicobacter pylori-induced injury

Polaprezinc (PZ) plays a role in the protection of gastric mucosa and inhibiting Helicobacter pylori (H. pylori) growth in vitro. The objective of this study was to determine the protective effects of PZ on human gastric epithelial cells (GES-1) against H. pylori-induced damage, while also examining heat shock protein 70 (HSP70) as a potential underlying factor in this protection. Our findings revealed that PZ exerted bactericidal effects against H. pylori strains. We also observed that PZ mitigated the H. pylori-induced damage to GES-1 cells by increasing cell viability, reducing LDH release, and decreasing the secretion of pro-inflammatory factors such as MCP-1 and IL-6. Co-culturing PZ with GES-1 cells significantly up-regulated the GES-1 HSP70 expression in both a time and dose-dependent manner. Pre-incubating (for 12 h) or co-culturing (for 24 h) GES-1 cells with PZ reversed the down-regulation of HSP70 in GES-1 cells caused by H. pylori infection. However, when quercetin was used to inhibit the up-regulation of HSP70 in GES-1 cells, the protective effect of PZ on GES-1 cells was significantly reduced. Based on the results of this study, PZ exhibits a protective role on GES-1 cells against H. pylori injury, as well as a direct bactericidal effect on H. pylori. HSP70 is involved in the PZ-driven host cell protection against H. pylori injury. These findings provide insight into alternative strategies for H. pylori treatment.

Synthesis, Cellular Uptake, and Photodynamic Activity of Oligogalactosyl Zinc(II) Phthalocyanines

Invited for this month's cover is the group of Prof. Dennis K. P. Ng at The Chinese University of Hong Kong. The cover picture shows the selective internalization of molecules of a di-galactosyl zinc(II) phthalocyanine into a cancer cell. Upon light irradiation, these molecules are excited and interact with the endogenous oxygen to generate highly reactive singlet oxygen, which oxidatively damages the cellular components, leading to cell death eventually. More information can be found in the Research Article by Dennis K. P. Ng, and co-workers.

64Cu-DOTATATE Uptake in a Pulmonary Hamartoma

ABSTRACT

DOTATATE PET/CT is frequently used to evaluate indeterminant pulmonary nodules suspected to be pulmonary carcinoid. We report an unexpected case of pulmonary hamartoma demonstrating 64Cu-DOTATATE uptake in a 43-year-old woman with a slowly enlarging pulmonary nodule. Histopathological staining showed somatostatin receptor 2 expression on vascular endothelial cells and a proportion of cartilage and smooth muscle cells within the hamartoma.

Systematically evaluating DOTATATE and FDG as PET immuno-imaging tracers of cardiovascular inflammation

In recent years, cardiovascular immuno-imaging by positron emission tomography (PET) has undergone tremendous progress in preclinical settings. Clinically, two approved PET tracers hold great potential for inflammation imaging in cardiovascular patients, namely FDG and DOTATATE. While the former is a widely applied metabolic tracer, DOTATATE is a relatively new PET tracer targeting the somatostatin receptor 2 (SST2). In the current study, we performed a detailed, head-to-head comparison of DOTATATE-based radiotracers and [18F]F-FDG in mouse and rabbit models of cardiovascular inflammation. For mouse experiments, we labeled DOTATATE with the long-lived isotope [64Cu]Cu to enable studying the tracer's mode of action by complementing in vivo PET/CT experiments with thorough ex vivo immunological analyses. For translational PET/MRI rabbit studies, we employed the more widely clinically used [68Ga]Ga-labeled DOTATATE, which was approved by the FDA in 2016. DOTATATE's pharmacokinetics and timed biodistribution were determined in control and atherosclerotic mice and rabbits by ex vivo gamma counting of blood and organs. Additionally, we performed in vivo PET/CT experiments in mice with atherosclerosis, mice subjected to myocardial infarction and control animals, using both [64Cu]Cu-DOTATATE and [18F]F-FDG. To evaluate differences in the tracers' cellular specificity, we performed ensuing ex vivo flow cytometry and gamma counting. In mice subjected to myocardial infarction, in vivo [64Cu]Cu-DOTATATE PET showed higher differential uptake between infarcted (SUVmax 1.3, IQR, 1.2-1.4, N = 4) and remote myocardium (SUVmax 0.7, IQR, 0.5-0.8, N = 4, p = 0.0286), and with respect to controls (SUVmax 0.6, IQR, 0.5-0.7, N = 4, p = 0.0286), than [18F]F-FDG PET. In atherosclerotic mice, [64Cu]Cu-DOTATATE PET aortic signal, but not [18F]F-FDG PET, was higher compared to controls (SUVmax 1.1, IQR, 0.9-1.3 and 0.5, IQR, 0.5-0.6, respectively, N = 4, p = 0.0286). In both models, [64Cu]Cu-DOTATATE demonstrated preferential accumulation in macrophages with respect to other myeloid cells, while [18F]F-FDG was taken up by macrophages and other leukocytes. In a translational PET/MRI study in atherosclerotic rabbits, we then compared [68Ga]Ga-DOTATATE and [18F]F-FDG for the assessment of aortic inflammation, combined with ex vivo radiometric assays and near-infrared imaging of macrophage burden. Rabbit experiments showed significantly higher aortic accumulation of both [68Ga]Ga-DOTATATE and [18F]F-FDG in atherosclerotic (SUVmax 0.415, IQR, 0.338-0.499, N = 32 and 0.446, IQR, 0.387-0.536, N = 27, respectively) compared to control animals (SUVmax 0.253, IQR, 0.197-0.285, p = 0.0002, N = 10 and 0.349, IQR, 0.299-0.423, p = 0.0159, N = 11, respectively). In conclusion, we present a detailed, head-to-head comparison of the novel SST2-specific tracer DOTATATE and the validated metabolic tracer [18F]F-FDG for the evaluation of inflammation in small animal models of cardiovascular disease. Our results support further investigations on the use of DOTATATE to assess cardiovascular inflammation as a complementary readout to the widely used [18F]F-FDG.

Organometallic Fe2(μ-SH)2(CO)4(CN)2 Cluster Allows the Biosynthesis of the [FeFe]-Hydrogenase with Only the HydF Maturase

The biosynthesis of the active site of the [FeFe]-hydrogenases (HydA1), the H-cluster, is of interest because these enzymes are highly efficient catalysts for the oxidation and production of H2. The biosynthesis of the [2Fe]H subcluster of the H-cluster proceeds from simple precursors, which are processed by three maturases: HydG, HydE, and HydF. Previous studies established that HydG produces an Fe(CO)2(CN) adduct of cysteine, which is the substrate for HydE. In this work, we show that by using the synthetic cluster [Fe2(μ-SH)2(CN)2(CO)4]2- active HydA1 can be biosynthesized without maturases HydG and HydE.

THE PECULIARITIES OF MORPOLOGICAL CHANGES OF RATS' OVARY AND BIOCHEMICAL STATE UNDER THE DAMAGE WITH DIFFERENT DOSES OF LEAD ACETATE

OBJECTIVE

The aim of the study was to study the effect of low and high doses of lead acetate on biochemical parameters and morphological status of rat ovaries in the experiment.

PATIENTS AND METHODS

Materials and methods: The study was performed on 36 nonlinear female rats weighing 180-210 g, aged 4 months, divided into 3 experimental groups: I - control (C), II - rats, which were given 30 days to drink a solution of lead acetate with at the rate of 0,05 mg / kg of animal weight, group III - rats, which were given for 30 days to drink a solution of lead acetate at the rate of 60 mg/kg of animal weight. Biochemical research methods were included determination of diene conjugate concentration in animals' blood, concentration of TBA-active products, study of oxidative modification of proteins in blood plasma, determination of superoxide dismutase and catalase activities. Endogenous intoxication was assessed by the definition of medium-mass molecules, the content was expressed in units of extinction. The material for light microscopy investigation from the ovary was performed according to the generally accepted method.

RESULTS

Results: Lead acetate causes activation of peroxidation of lipids and proteins in the body of female rats, which is directly dependent on the dose of lead. In response to the activation of free radical oxidation there are changes in the antioxidant system, which depend on the dose of lead acetate: at a dose of 0.05 mg / kg superoxide dismutase and catalase activity increase, at a dose of 60 mg / kg superoxide dismutase and catalase activity. Small doses of lead do not cause endogenous intoxication. Lead acetate causes the development of endogenous intoxication in animals only in large doses: increases the formation of toxic compounds, cell apoptosis, decreased excretory function of the kidneys, which is associated with multiorgan disorders. As a result of the action of lead acetate, morphological changes of the ovaries were observed, which increased with increasing dose of lead acetate. There was a dose-dependent decrease in massometric parameters, the number of follicles and changes in the thickness of the surface structures of the ovary, which is more pronounced at 60 mg/kg.

CONCLUSION

Conclusions: Under the influence of small and large doses of lead acetate on biochemical changes in blood and morphological changes in the ovaries in male rats the oxidative stress is developed. Under the influence of small doses, the changes are adaptive, and under the influence of large doses - damaging.

L-Ascorbic Acid and Curcumin prevents Brain Damage-induced via Lead Acetate in Rats: Possible Mechanisms

Lead acetate (lead ac.) is a widespread ecological toxicant that can cause marked neurotoxicity and decline in brain functions. This study aimed to evaluate the possible neuroprotective role of L-ascorbic (ASCR) and curcumin (CRCM) alone or together against lead ac.-induced neurotoxicity. Rats were injected with lead ac. then treated orally with ASCR and CRCM alone or in combination for seven days. Lead ac. caused elevation in brain tumor necrosis factor- α (TNF-α), interleukin-6 (IL-6), caspase-3, and malondialdehyde (MDA) levels, while superoxide dismutase (SOD), reduced glutathione (GSH) as well as the expression of brain-derived neurotrophic factor (BDNF), cAMP response element-binding (CREB) and Beclin1 were down-regulated. Expressions of C/EBP homologous protein (CHOP) and mammalian Target of rapamycin kinase (mTOR) were upregulated in brain tissues matched with the control group. Histopathological examination supported the previously mentioned parameters, the administration of the antioxidants in question modulated all the altered previous parameters. The combination regimen achieved the superlative results in the antagonizing lead ac.-induced neurotoxicity via its antioxidant and anti-apoptotic activities.

Evaluation of 68Ga-DOTATATE uptake at the pituitary region and the biochemical response to somatostatin analogs in acromegaly

PURPOSE

Acromegaly is associated with many comorbidities and increased mortality. The first-line treatment is transsphenoidal surgery. However, many patients also need adjuvant drug treatment after surgery. Somatostatin analog (SSA), which suppresses GH secretion by somatotrophs by binding to the SSTR2 receptor, is the first choice. Nevertheless, 50% of patients are partially or totally resistant to SSA, so predictive factors of response are helpful to individualize drug treatment. ⁶⁸GaDOTATATE PET/CT has emerged as the gold-standard method in the diagnosis and follow-up of gastroenteropancreatic neuroendocrine tumors, which also express SSTR. Our objective was to evaluate whether ⁶⁸Ga-DOTATATE uptake (SUV max) at the pituitary region of patients on SSA therapy would be useful as a drug response predictor without the need of tumoral tissue.

METHODS

Fifteen acromegalics patients on SSA treatment for at least 6 months were underwent to ⁶⁸Ga-DOTATATE PET/CT at the nuclear medicine service. There was an SSA complete response group (n = 5), defined as GH < 1 µg/L and IFG-1 in the normal range for gender and age, and a group that did not meet these criteria (n = 10).

RESULTS

As a result, we did not find out a significantly higher SUV max in the complete response group (p = 0.0576) to SSA. However, we found a significant inverse relationship between postoperative GH values and the SUVmax at the sella turcica (p = 0.0188), probably reflecting tumor SSTR2 expression.

CONCLUSION

Thus, after this initial evaluation, ⁶⁸GaDOTATATE PET/CT should be better studied to assess its usefulness in the follow-up of acromegalic patients.

Effects of Substitution on Cytotoxicity of Diphenyl Ditelluride in Cultured Vascular Endothelial Cells

Among organic–inorganic hybrid molecules consisting of organic structure(s) and metal(s), only few studies are available on the cytotoxicity of nucleophilic molecules. In the present study, we investigated the cytotoxicity of a nucleophilic organotellurium compound, diphenyl ditelluride (DPDTe), using a cell culture system. DPDTe exhibited strong cytotoxicity against vascular endothelial cells and fibroblasts along with high intracellular accumulation but showed no cytotoxicity and had less accumulation in vascular smooth muscle cells and renal epithelial cells. The cytotoxicity of DPDTe decreased when intramolecular tellurium atoms were replaced with selenium or sulfur atoms. Electronic state analysis revealed that the electron density between tellurium atoms in DPDTe was much lower than those between selenium atoms of diphenyl diselenide and sulfur atoms of diphenyl disulfide. Moreover, diphenyl telluride did not accumulate and exhibit cytotoxicity. The cytotoxicity of DPDTe was also affected by substitution. p-Dimethoxy-DPDTe showed higher cytotoxicity, but p-dichloro-DPDTe and p-methyl-DPDTe showed lower cytotoxicity than that of DPDTe. The subcellular distribution of the compounds revealed that the compounds with stronger cytotoxicity showed higher accumulation rates in the mitochondria. Our findings suggest that the electronic state of tellurium atoms in DPDTe play an important role in accumulation and distribution of DPDTe in cultured cells. The present study supports the hypothesis that nucleophilic organometallic compounds, as well as electrophilic organometallic compounds, exhibit cytotoxicity by particular mechanisms.

Synchrotron-Based Fourier-Transform Infrared Micro-Spectroscopy (SR-FTIRM) Fingerprint of the Small Anionic Molecule Cobaltabis(dicarbollide) Uptake in Glioma Stem Cells

The anionic cobaltabis (dicarbollide) [3,3'-Co(1,2-C2B9H11)2]-, [o-COSAN]-, is the most studied icosahedral metallacarborane. The sodium salts of [o-COSAN]- could be an ideal candidate for the anti-cancer treatment Boron Neutron Capture Therapy (BNCT) as it possesses the ability to readily cross biological membranes thereby producing cell cycle arrest in cancer cells. BNCT is a cancer therapy based on the potential of 10B atoms to produce α particles that cross tissues in which the 10B is accumulated without damaging the surrounding healthy tissues, after being irradiated with low energy thermal neutrons. Since Na[o-COSAN] displays a strong and characteristic ν(B-H) frequency in the infrared range 2.600-2.500 cm-1, we studied the uptake of Na[o-COSAN] followed by its interaction with biomolecules and its cellular biodistribution in two different glioma initiating cells (GICs), mesenchymal and proneural respectively, by using Synchrotron Radiation-Fourier Transform Infrared (FTIR) micro-spectroscopy (SR-FTIRM) facilities at the MIRAS Beamline of ALBA synchrotron light source. The spectroscopic data analysis from the bands in the regions of DNA, proteins, and lipids permitted to suggest that after its cellular uptake, Na[o-COSAN] strongly interacts with DNA strings, modifies proteins secondary structure and also leads to lipid saturation. The mapping suggests the nuclear localization of [o-COSAN]-, which according to reported Monte Carlo simulations may result in a more efficient cell-killing effect compared to that in a uniform distribution within the entire cell. In conclusion, we show pieces of evidence that at low doses, [o-COSAN]- translocates GIC cells' membranes and it alters the physiology of the cells, suggesting that Na[o-COSAN] is a promising agent to BNCT for glioblastoma cells.

Analytic and chemometric assessments of the native probiotic bacteria and inulin effects on bioremediation of lead salts

BACKGROUND

Lead (Pb²⁺ ) is one of the most toxic heavy metals and can be found in various quantities in the environment. The five native probiotic bacteria and inulin were used to assess in vitro lead nitrate and lead acetate binding capacities, as well as removal potentials.

RESULTS

The highest decrease in media pH was seen for samples containing a combination of Lactobacillus paracasei IRBC-M 10784, lead nitrate and inulin (5.30 ± 0.012). The presence of inulin in the environment accelerated decreases in the pH of all samples with no significance. In all groups, lead nitrate-containing samples included maximum pH decreases. From the highest to the lowest, the ability of lead removal was linked to Lactobacillus acidophilus PTCC-1932 (88.48%), Bifidobacterium bifidum BIA-7 (85.32%), Bifidobacterium lactis BIA-6 (85.24%), Lactobacillus rhamnosus IBRC-M 10782 (83.18%) and L. paracasei IRBC-M 10784 (80.66%). Most species included the highest decrease in lead nitrate. Fourier-transform infrared spectroscopy (FTIR) analysis demonstrated that various functional groups (hydroxyl, carboxylic, carbonyl, amino and amide binds) on the bacterial cell wall were involved in lead ion binding during incubation. Principal component analysis of the FTIR results showed differences with respect to treated groups and control groups.

CONCLUSION

The results obtained in the present study reveal that the simultaneous use of native probiotics and inulin can be an effective and safe approach for removing various toxic substances, especially Pb. © 2021 Society of Chemical Industry.

Speciation Analysis of Gadolinium in the Water-Insoluble Rat Brain Fraction After Administration of Gadolinium-Based Contrast Agents

PURPOSE

To date, the analysis of gadolinium (Gd) speciation in the brain of animals administered with macrocyclic and linear Gd-based contrast agents (GBCAs) has been limited to Gd soluble in mild buffers. Under such conditions, less than 30% of the brain tissue was solubilized and the extraction recoveries of GBCAs into the aqueous phase were poor, especially in the case of the linear GBCAs. The aim of this study was to find the conditions to solubilize the brain tissue (quasi-)completely while preserving the Gd species present. The subsequent analysis using size exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS) was intended to shed the light on the speciation of the additionally recovered Gd.

METHODS

Four groups of healthy female Sprague Dawley rats (SPF/OFA rats; Charles River, L'Arbresle, France) received randomly 5 intravenous injections (1 injection per week during 5 consecutive weeks) of either gadoterate meglumine, gadobenate dimeglumine, gadodiamide (cumulated dose of 12 mmol/kg), or no injection (control group). The animals were sacrifice 1 week (W1) after the last injection. Brain tissues were solubilized with urea solution, whereas tissues extracted with water served as controls. Total Gd concentrations were determined in the original brain tissue and its soluble and insoluble fractions by inductively coupled plasma-mass spectrometry (ICP-MS) to calculate the Gd accumulation and extraction efficiency. Size exclusion chromatography coupled to ICP-MS was used to monitor the speciation of Gd in the soluble fractions. The stability of GBCAs in the optimum conditions was monitored by spiking the brain samples from the untreated animals. The column recoveries were precisely determined in the purpose of the discrimination of weakly and strongly bound Gd complexes. The identity of the eluted species was explored by the evaluation of the molecular size and retention time matching with Gd chelates and ferritin standard. The speciation analyses were carried out for 2 different brain structures, cortex and cerebellum.

RESULTS

The combination of water and urea extractions (sequential extraction) managed to solubilize efficiently the brain tissue (97% ± 1%) while preserving the stability of the initially injected form of GBCA. For macrocyclic gadoterate, 97% ± 1% and 102% ± 3% of Gd initially present in the cortex and cerebellum were extracted to the soluble fraction. For gadobenate, similar amounts of Gd (49% ± 1% and 46% ± 4%) were recovered from cortex and cerebellum. For gadodiamide, 48% ± 2% of Gd was extracted from cortex and 34% ± 1% from cerebellum. These extraction efficiencies were higher than reported elsewhere. The SEC-ICP-MS and the column recovery determination proved that Gd present at low nmol/g levels in brain tissue was exclusively in the intact GBCA form in all the fractions of brain from the animals treated with gadoterate. For the linear GBCAs (gadobenate and gadodiamide), 3 Gd species of different hydrodynamic volumes were detected in the urea-soluble fraction: (1) larger than 660 kDa, (2) approximately 440 kDa, and (3) intact GBCAs. The species of 440 kDa corresponded, on the basis of the elution volume, to a Gd3+ complex with ferritin. Gd3+ was also demonstrated by SEC-ICP-MS to react with the ferritin standard in 100 mM ammonium acetate (pH 7.4). In contrast to macrocyclic gadoterate, for linear GBCAs, the column recovery was largely incomplete, suggesting the presence of free, hydrolyzed, or weakly bound Gd3+ with endogenous ligands.

CONCLUSIONS

The sequential extraction of rat brain tissue with water and urea solution resulted in quasi-complete solubilization of the tissue and a considerable increase in the recoveries of Gd species in comparison with previous reports. The macrocyclic gadoterate was demonstrated to remain intact in the brain 1 week after administration to rats. The linear GBCAs gadobenate and gadodiamide underwent ligand exchange reactions resulting in the presence of a series of Gd3+ complexes of different strength with endogenous ligands. Ferritin was identified as one of the macromolecules reacting with Gd3+. For the linear GBCAs, 3% of the insoluble brain tissue was found to contain more than 50% of Gd in unidentified form(s).

Leonardite iron humate and synthetic iron chelate mixtures in Glycine max nutrition

BACKGROUND

The aim of this work was to study the possible synergic effect between mixtures with iron leonardite humate (L/Fe3+ ) and synthetic chelates iron (Ch/Fe3+ : o,oEDDHA /Fe3+ or HBED/Fe3+ ), and to reevaluate the classical chelate shuttle-effect model. Different molar ratios of L/Fe3+ :Ch/Fe3+ , different doses, and different sampling times were used in hydroponic and soil experiments using soybean (Glycine max) as a model Strategy I crop in calcareous conditions. Ligand competition between the humate and chelating agents was also examined.

RESULTS

Iron humate participates in the chelate shuttle mechanism, providing available Fe to the chelating agent and then to the plants, showing a slight synergic effect. After a few days, the contribution of the chelates to the Fe nutrition decreases substantially, but the contribution of the humates is maintained.

CONCLUSIONS

The most efficient ratio was two parts of iron humates and one part of iron chelate. In particular, HBED/Fe3+ was the most suitable iron chelate because its lasting effect fits the iron humate long-term effect better. The soluble iron in soil increased and the shoot-to-root iron translocation improved due to a synergic effect by a shuttle effect exerted by iron chelate in the mixture. © 2021 Society of Chemical Industry.

68Ga-DOTATATE PET/CT Uptake in Prostate With an Incidental Finding of Prostatic Acinar Adenocarcinoma and Metastatic Neuroendocrine Cancer to the Liver

ABSTRACT

A 69-year-old man with history of metastatic neuroendocrine tumor presented for initial staging with 68Ga-DOTATE PET/CT. 68Ga-DOTATATE PET/CT showed incidental focal increased DOTATATE uptake in the left apical prostate tissue, which was thought to be of benign etiology. Digital rectal examination later was consistent with a palpable nodule along with elevated prostate-specific antigen of 7.0 ng/mL. MRI of prostate demonstrated a 3.8-cm lesion followed by a targeted biopsy that revealed prostatic acinar adenocarcinoma. Chronic inflammatory cell infiltrates were also noted on biopsy, and this may have been the cause of increased DOTATATE uptake seen on 68Ga-DOTATATE PET/CT study.

Hydrogel-Induced Cell Membrane Disruptions Enable Direct Cytosolic Delivery of Membrane-Impermeable Cargo

Intracellular delivery of membrane-impermeable cargo offers unique opportunities for biological research and the development of cell-based therapies. Despite the breadth of available intracellular delivery tools, existing protocols are often suboptimal and alternative approaches that merge delivery efficiency with both biocompatibility, as well as applicability, remain highly sought after. Here, a comprehensive platform is presented that exploits the unique property of cationic hydrogel nanoparticles to transiently disrupt the plasma membrane of cells, allowing direct cytosolic delivery of uncomplexed membrane-impermeable cargo. Using this platform, which is termed Hydrogel-enabled nanoPoration or HyPore, the delivery of fluorescein isothiocyanate (FITC)-dextran macromolecules in various cancer cell lines and primary bovine corneal epithelial cells is convincingly demonstrated. Of note, HyPore demonstrates efficient FITC-dextran delivery in primary human T cells, outperforming state-of-the-art electroporation-mediated delivery. Moreover, the HyPore platform enables cytosolic delivery of functional proteins, including a histone-binding nanobody as well as the enzymes granzyme A and Cre-recombinase. Finally, HyPore-mediated delivery of the MRI contrast agent gadobutrol in primary human T cells significantly improves their T₁ -weighted MRI signal intensities compared to electroporation. Taken together, HyPore is proposed as a straightforward, highly versatile, and cost-effective technique for high-throughput, ex vivo manipulation of primary cells and cell lines.

Incidental Finding of a Parotid Basal Cell Adenoma With High Tracer Uptake on 68Ga-DOTATOC PET/CT

ABSTRACT

A 67-year-old man was referred to our department to undergo a 68Ga-DOTATOC PET/CT during the systematic follow-up of a small intestine neuroendocrine tumor. PET revealed an incidental focal increased uptake of 68Ga-DOTATOC matching with a left intraparotid lesion on the combined contrast-enhanced CT, suggestive of a benign salivary tumor. An MRI was performed to characterize this lesion, and finally, the patient underwent surgery. Histological analysis confirmed the presence of a basal cell adenoma.

Unsuspected Bladder Diverticulum Resulted in False-Positive 68Ga-DOTATATE Uptake

ABSTRACT

A 67-year-old woman with medullary thyroid cancer was referred for a 68Ga-DOTATATE PET/CT scan for staging. The images showed abnormal activity in the left thyroid gland and the left cervical lymph nodes. Surprisingly, increased activity was also noted in the posterolateral aspect of the urinary bladder without corresponding anatomical abnormality. This activity disappeared after urination, suggesting false-positive uptake due to bladder diverticulum.

Controlled Ligand Exchange Between Ruthenium Organometallic Cofactor Precursors and a Naïve Protein Scaffold Generates Artificial Metalloenzymes Catalysing Transfer Hydrogenation

Many natural metalloenzymes assemble from proteins and biosynthesised complexes, generating potent catalysts by changing metal coordination. Here we adopt the same strategy to generate artificial metalloenzymes (ArMs) using ligand exchange to unmask catalytic activity. By systematically testing RuII (η6 -arene)(bipyridine) complexes designed to facilitate the displacement of functionalised bipyridines, we develop a fast and robust procedure for generating new enzymes via ligand exchange in a protein that has not evolved to bind such a complex. The resulting metal cofactors form peptidic coordination bonds but also retain a non-biological ligand. Tandem mass spectrometry and 19 F NMR spectroscopy were used to characterise the organometallic cofactors and identify the protein-derived ligands. By introduction of ruthenium cofactors into a 4-helical bundle, transfer hydrogenation catalysts were generated that displayed a 35-fold rate increase when compared to the respective small molecule reaction in solution.

Cellular Uptake of the ATSM-Cu(II) Complex under Hypoxic Conditions

The Cu(II)-diacetyl-bis (N4-methylthiosemicarbazone) complex (ATSM-Cu(II)) has been suggested as a promising positron emission tomography (PET) agent for hypoxia imaging. Several in-vivo studies have shown its potential to detect hypoxic tumors. However, its uptake mechanism and its specificity to various cancer cell lines have been less studied. Herein, we tested ATSM-Cu(II) toxicity, uptake, and reduction, using four different cell types: (1) mouse breast cancer cells (DA-3), (2) human embryonic kidney cells (HEK-293), (3) breast cancer cells (MCF-7), and (4) cervical cancer cells (Hela) under normoxic and hypoxic conditions. We showed that ATSM-Cu(II) is toxic to breast cancer cells under normoxic and hypoxic conditions; however, it is not toxic to normal HEK-293 non-cancer cells. We showed that the Cu(I) content in breast cancer cell after treatment with ATSM-Cu(II) under hypoxic conditions is higher than in normal cells, despite that the uptake of ATSM-Cu(II) is a bit higher in normal cells than in breast cancer cells. This study suggests that the redox potential of ATSM-Cu(II) is higher in breast cancer cells than in normal cells; thus, its toxicity to cancer cells is increased.

68Ga-DOTATATE Uptake in Primary Breast Cancer

ABSTRACT

68Ga-DOTA peptides have revolutionized the imaging of neuroendocrine tumors because the agents are specific to somatostatin receptors. However, other tumors, including breast cancer, have been shown to express somatostatin receptors. We present the case of a 74-year-old woman with primary cardiac paraganglioma, who was found to have 68Ga-DOTATATE activity in the breast on staging PET/CT. Subsequent breast imaging workup and biopsy confirmed primary invasive lobular breast cancer, which was not 18F-FDG-avid on prior FDG PET/CT. Our case is in alignment with prior studies that suggest that 68Ga-DOTA peptides may play a future role in imaging breast cancer patients.

Gallbladder Uptake Mimicking Liver Metastasis on 177Lu-DOTATATE Posttherapy Scan Gallbladder Uptake on 177Lu-DOTATATE Scan

ABSTRACT

We represent the case of a 61-year-old man with atypical carcinoid tumor of the lung. On posttherapy 177Lu-DOTATATE whole-body scan, focal intense uptake in the inferomedial side of the liver was detected. Pretherapy 68Ga-DOTATATE PET/CT showed no sign of liver metastasis, and posttherapy diagnostic dynamic liver MRI is used to exclude metastatic liver disease. Focal intense uptake was attributed to physiological gallbladder uptake.

Building up PtII -Thiosemicarbazone-Lysine-sC18 Conjugates

Three chiral tridentate N^N^S coordinating pyridine-carbaldehyde (S)-N4-(α-methylbenzyl)thiosemicarbazones (HTSCmB) were synthesised along with lysine-modified derivatives. One of them was selected and covalently conjugated to the cell-penetrating peptide sC18 by solid-phase peptide synthesis. The HTSCmB model ligands, the HTSCLp derivatives and the peptide conjugate rapidly and quantitatively form very stable PtII chlorido complexes [Pt(TSC)Cl] when treated with K2 PtCl4 in solution. The Pt(CN) derivatives were obtained from one TSCmB model complex and the peptide conjugate complex through Cl- →CN- exchange. Ligands and complexes were characterised by NMR, IR spectroscopy, HR-ESI-MS and single-crystal XRD. Intriguingly, no decrease in cell viability was observed when testing the biological activity of the lysine-tagged HdpyTSCLp, its sC18 conjugate HdpyTSCL-sC18 or the PtCl and Pt(CN) conjugate complexes in three different cell lines. Thus, given the facile and effective preparation of such Pt-TSC-peptide conjugates, these systems might pave the way for future use in late-stage labelling with Pt radionuclides and application in nuclear medicine.

Warthin Tumor Incidentally Detected on PET/CT Showing Both 68Ga-DOTANOC and 18F-FDG Uptake

ABSTRACT

A patient with moderately differentiated pancreatic neuroendocrine tumor with synchronous multifocal liver metastases was referred for further staging with PET/CT. The examinations were performed on 2 consecutive days and showed mild 68Ga-DOTANOC and intense 18F-FDG uptake in an incidental right parotid nodule. Differential diagnoses include primary or metastatic neuroendocrine tumor, malignant or benign primary parotid tumor, and intraparotid lymph node. Histology revealed characteristics of a Warthin tumor. While focal FDG uptake in Warthin tumor is frequently described, the somatostatin expression was rarely reported. This clinical case describes 68Ga-DOTANOC and 18F-FDG uptake in a parotid Warthin tumor histologically confirmed.

Clinical Assessment of 177Lu-DOTATATE Quantification by Comparison of SUV-Based Parameters Measured on Both Post-PRRT SPECT/CT and 68Ga-DOTATOC PET/CT in Patients With Neuroendocrine Tumors: A Feasibility Study

PATIENTS AND METHODS

Patients with WD-GEP-NET who benefited from a pretherapeutic 68Ga-DOTATOC PET/CT and a 177Lu-DOTATATE SPECT/CT after the cycle 1 of peptide receptor radionuclide therapy were prospectively included. SPECT/CT acquisitions were performed on a system calibrated with a conversion factor of 9.48 counts/MBq per second and were reconstructed with an iterative algorithm allowing quantification using the SPECTRA Quant software (MIM Software, Cleveland, OH). For each patient, different SUV parameters were recorded on both PET/CT (Ga parameters) and SPECT/CT (Lu parameters) for comparison: physiological uptakes (liver/spleen), tumor uptake (1-10/patient; SUVmax, SUVmean, SUVpeak, MTV), tumor-to-liver and tumor-to-spleen ratios according to liver/spleen SUVmax and SUVmean (TLRmax, TLRmean, TSRmax, and TSRmean, respectively).

RESULTS

Ten patients (8 female; 2 male) aged from 50 to 83 years presenting with a metastatic progressive WD-GEP-NET (7 small intestine, 2 pancreas, 1 rectum) were included. Median values of lesional Lu-SUV were significantly lower than the corresponding Ga-SUV (P < 0.001), whereas median values of lesional Lu-MTV, Lu-TLR, and Lu-TSR were significantly higher than the corresponding Ga-MTV, Ga-TLR, and Ga-TSR (P < 0.02). Pearson correlation coefficients were strong for both SUV and MTV parameters (0.779-0.845), weak for TLR parameters (0.365-0.394), and moderate-to-strong for TSR parameters (0.676-0.750).

CONCLUSIONS

Our results suggest the feasibility of 177Lu-DOTATATE SPECT/CT quantification in clinical practice and show a strong correlation of several SUV-based parameters with the corresponding in 68Ga-DOTATOC PET/CT.

Differentiation of insulinoma from accessory spleen by 99mTc-labelled heat-denaturated red blood cell scintigraphy: case report

BACKGROUND

Neuroendocrine tumors (NETs) are rare tumors harboring overexpression of somatostatin receptors (SSTRs) on their cell membrane. Because some organs, such as the spleen, adrenal glands and liver, physiologically express SSTR, it might be challenging to distinguish some pancreatic NETs located in the pancreatic tail from the accessory spleen next to the splenic hilum. In this manuscript, we report a case with hypoglycemia attack and 2 different masses displayed by Gallium 68-tetraazacyclododecane tetraacetic acid-octreotate (⁶⁸Ga-DOTATATE) positron emission tomography/computed tomography (PET/CT).

CASE PRESENTATION

A 63-year-old woman presented to the hospital with confusion and profuse sweating. Biochemical diagnosis of insulinoma was established. ⁶⁸Ga-DOTATATE PET/CT revealed two masses with increased tracer uptake located adjacent to the splenic hilum and inferior pole of the spleen which were initially reported as two separate accessory spleens. Then, ^99mTc-labelled heat-denaturated red blood cell (^99mTc-HDRBC) scintigraphy-single-photon emission computed tomography (SPECT)/CT was performed to distinguish a NET in the pancreatic tail from accessory spleen at the splenic hilum. Enhanced tracer uptake remained in the inferior pole of spleen, but not in the splenic hilum. The lesions were suggestive of insulinoma in the pancreatic tail and an accessory spleen adjacent to the inferior pole of the spleen.

CONCLUSION

Approximately 10% of the population have an accessory spleen which can show similar imaging characteristics with pancreatic NETs, especially if located in the pancreatic tail. In our presented case, ^99mTc-HDRBC scintigraphy-SPECT/CT is a useful nuclear medicine method to differentiate a NET in the pancreatic tail from accessory spleen at the splenic hilum which may avoid unnecessary surgeries in the presence of enhanced tracer uptake or vice versa.

Seesaw conformations of Npl4 in the human p97 complex and the inhibitory mechanism of a disulfiram derivative

p97, also known as valosin-containing protein (VCP) or Cdc48, plays a central role in cellular protein homeostasis. Human p97 mutations are associated with several neurodegenerative diseases. Targeting p97 and its cofactors is a strategy for cancer drug development. Despite significant structural insights into the fungal homolog Cdc48, little is known about how human p97 interacts with its cofactors. Recently, the anti-alcohol abuse drug disulfiram was found to target cancer through Npl4, a cofactor of p97, but the molecular mechanism remains elusive. Here, using single-particle cryo-electron microscopy (cryo-EM), we uncovered three Npl4 conformational states in complex with human p97 before ATP hydrolysis. The motion of Npl4 results from its zinc finger motifs interacting with the N domain of p97, which is essential for the unfolding activity of p97. In vitro and cell-based assays showed that the disulfiram derivative bis-(diethyldithiocarbamate)-copper (CuET) can bypass the copper transporter system and inhibit the function of p97 in the cytoplasm by releasing cupric ions under oxidative conditions, which disrupt the zinc finger motifs of Npl4, locking the essential conformational switch of the complex.

68Ga-Prostate-Specific Membrane Antigen PET/CT Uptake in Intraventricular Meningioma in the Choroid Plexus

A 68-year-old man in whom a prostate cancer biochemical recurrence was being investigated was referred for a full-body Ga-prostate-specific membrane antigen PET/CT. Focal uptake in a lesion on the choroid plexus projection was detected. Patient had no neurological complaints. A previous MRI performed 4 years ago showed the same lesion. According to the location and radiological and clinical characteristics, the diagnosis of meningioma was defined. The interpretation of prostate-specific membrane antigen PET/CT must take into account the low frequency of metastases in sites such as the central nervous system, and the possibility of intense uptake in lesions unrelated to prostate cancer.

Functional and morphological adaptation in DNA protocells via signal processing prompted by artificial metalloenzymes

For life to emerge, the confinement of catalytic reactions within protocellular environments has been proposed to be a decisive aspect to regulate chemical activity in space¹. Today, cells and organisms adapt to signals^2-6 by processing them through reaction networks that ultimately provide downstream functional responses and structural morphogenesis^7,8. Re-enacting such signal processing in de novo-designed protocells is a profound challenge, but of high importance for understanding the design of adaptive systems with life-like traits. We report on engineered all-DNA protocells⁹ harbouring an artificial metalloenzyme¹⁰ whose olefin metathesis activity leads to downstream morphogenetic protocellular responses with varying levels of complexity. The artificial metalloenzyme catalyses the uncaging of a pro-fluorescent signal molecule that generates a self-reporting fluorescent metabolite designed to weaken DNA duplex interactions. This leads to pronounced growth, intraparticular functional adaptation in the presence of a fluorescent DNA mechanosensor¹¹ or interparticle protocell fusion. Such processes mimic chemically transduced processes found in cell adaptation and cell-to-cell adhesion. Our concept showcases new opportunities to study life-like behaviour via abiotic bioorthogonal chemical and mechanical transformations in synthetic protocells. Furthermore, it reveals a strategy for inducing complex behaviour in adaptive and communicating soft-matter microsystems, and it illustrates how dynamic properties can be upregulated and sustained in micro-compartmentalized media.

Differential response of human T-lymphocytes to arsenic and uranium

Elevated levels of arsenic and uranium have been detected in water sources near abandoned uranium mines in the Southwest. Evidence suggests uranium exposure increases the likelihood of immune dysfunction and this study investigates the impact of arsenic and uranium on human immune cell lines. Concentration-dependent cytotoxicity occurred following exposure to arsenite, whereas cells remained viable after 48 -h treatment with up to 100 μM uranyl acetate despite uptake of uranium into cells. Arsenite stimulated an oxidative stress response as detected by Nrf-2 nuclear accumulation and induction of HMOX-1 and NQO1, which was not detected with up to 30 μM uranyl acetate. Cellular oxidative stress can promote DNA damage and arsenite, but not uranium, stimulated DNA damage as measured by pH2AX. Arsenic enhanced the cytotoxic response to etoposide suggesting an inhibition of DNA repair, unlike uranium. Similarly, uranium did not inhibit PARP-1 activity. Because uranium reportedly stimulates oxidative stress, DNA damage and cytotoxicity in adherent epithelial cells, the current study suggests distinct cell type differences in response to uranium that may relate to generation of oxidative stress and associated downstream consequences. Delineating the actions of uranium across different cell targets will be important for understanding the potential health effects of uranium exposures.

Evaluating UiO-66 Metal-Organic Framework Nanoparticles as Acid-Sensitive Carriers for Pulmonary Drug Delivery Applications

Developing novel drug carriers for pulmonary delivery is necessary to achieve higher efficacy and consistency for treating pulmonary diseases while limiting off-target side effects that occur from alternative routes of administration. Metal-organic frameworks (MOFs) have recently emerged as a class of materials with characteristics well-suited for pulmonary drug delivery, with chemical tunability, high surface area, and pore size, which will allow for efficient loading of therapeutic cargo and deep lung penetration. UiO-66, a zirconium and terephthalic acid-based MOF, has displayed notable chemical and physical stability and potential biocompatibility; however, its feasibility for use as a pulmonary drug delivery vehicle has yet to be examined. Here, we evaluate the use of UiO-66 nanoparticles (NPs) as novel pulmonary drug delivery vehicles and assess the role of missing linker defects in their utility for this application. We determined that missing linker defects result in differences in NP aerodynamics but have minimal effects on the loading of model and therapeutic cargo, cargo release, biocompatibility, or biodistribution. This is a critical result, as it indicates the robust consistency of UiO-66, a critical feature for pulmonary drug delivery, which is plagued by inconsistent dosage because of variable properties. Not only that, but UiO-66 NPs also demonstrate pH-dependent stability, with resistance to degradation in extracellular conditions and breakdown in intracellular environments. Furthermore, the carriers exhibit high biocompatibility and low cytotoxicity in vitro and are well-tolerated in in vivo murine evaluations of orotracheally administered NPs. Following pulmonary delivery, UiO-66 NPs remain localized to the lungs before clearance over the course of seven days. Our results demonstrate the feasibility of using UiO-66 NPs as a novel platform for pulmonary drug delivery through their tunable NP properties, which allow for controlled aerodynamics and internalization-dependent cargo release while displaying remarkable pulmonary biocompatibility.

Synthesis, Characterization and Biological Application of Pyrazolo[1,5-a]pyrimidine Based Organometallic Re(I) Complexes

The neutral rhenium(I) complexes (I-VI) of type [ReCl(CO)3Ln-] where L1 = 7-phenyl-5-(pyridin-2-yl)pyrazolo[1,5-a]pyrimidine, L2 = 7-(4-bromophenyl)-5-(pyridin-2-yl)pyrazolo[1,5-a]pyrimi- dine, L3 = 7-(4-chlorophenyl)-5-(pyridin-2-yl)pyrazolo[1,5-a]pyrimidine, L4 = 7-(2-chlorophenyl) -5-(pyridin-2-yl)pyrazolo[1,5-a]pyrimidine, L5 = 7-(4-methoxyphenyl)-5-(pyridin-2-yl)pyrazolo [1,5-a]pyrimidine, L6 = 5-(pyridin-2-yl)-7-(p-tolyl)pyrazolo[1,5-a]pyrimidine were synthesized and characterized by 13C-APT, 1H-NMR, IR, electronic spectra, magnetic moment and conductance measurement. The anti-proliferative activity on HCT116 cells by MTT assay suggests potent cytotoxic nature of complexes, even some complexes have better activity than standard drug cisplatin, oxaliplatin, and carboplatin. The complexes found to have better antimicrobial activity compare to pyrazolo pyrimidine ligands. The theoretical study of compounds-DNA interactions was examined by molecular docking as a supportive tool to the experimental data, which suggests the groove mode of binding. The values of docking energy for compounds-DNA interaction were found in the range of -230.31 to -288.34 kJ/mol. The intrinsic binding constant values of complexes (1.1-3.5×105 M-1) were found higher than the ligands (0.32-1.8×105 M-1).

New Microporous Lanthanide Organic Frameworks. Synthesis, Structure, Luminescence, Sorption, and Catalytic Acylation of 2-Naphthol

New metal-organic frameworks (MOF) with lanthanum(III), cerium(III), neodymium(III), europium(III), gadolinium(III), dysprosium(III), and holmium(III)] and the ligand precursor 1,3,5-tris(4-carboxyphenyl)-2,4,6-trimethylbenzene (H3L) were synthesized under solvothermal conditions. Single crystal x-ray analysis confirmed the formation of three-dimensional frameworks of [LnL(H2O)2]n·xDMF·yH2O for Ln = La, Ce, and Nd. From the nitrogen sorption experiments, the compounds showed permanent porosity with Brunauer-Emmett-Teller (BET) surface areas of about 400 m2/g, and thermal stability up to 500 °C. Further investigations showed that these Ln-MOFs exhibit catalytic activity, paving the way for potential applications within the field of catalysis.

Dinuclear Copper(II) Complexes with Schiff Bases Derived from 2-Hydroxy-5-Methylisophthalaldehyde and Histamine or 2-(2-Aminoethyl)pyridine and Their Application as Magnetic and Fluorescent Materials in Thin Film Deposition

Two Cu(II) complexes, 1 and 2, with tridentate Schiff bases derived from 2-hydroxy-5-methylisophthalaldehyde and histamine HL1 or 2-(2-aminoethyl)pyridine HL2, respectively, were obtained and characterized by X-ray crystallography, spectroscopic (UV-vis, fluorescence, IR, and EPR), magnetic, and thermal methods. Despite the fact that the chelate formed by the NNO ligand donors (C26-C25H2-C24H2-N23=C23H-C22-C19Ph(O1)-C2(Ph)-C3H=N3-C4H2-C5H2-C6 fragment) are identical, as well as the synthesis of Cu(II) complexes (Cu:L = 2:1 molar ratio) was performed in the same manner, the structures of the complexes differ significantly. The complex 1, {[Cu2(L1)Cl2]2[CuCl4]}·2MeCN·2H2O, consists of [Cu2(L1)Cl2]+ units in which Cu(II) ions are bridged by the HL1 ligand oxygen and each of these Cu(II) ions is connected with Cu(II) ions of the next dimeric unit via two bridging Cl- ions to form a chain structure. In the dinuclear [Cu2(L2)Cl3]0.5MeCN complex 2, each Cu(II) is asymmetrically bridged by the ligand oxygen and chloride anions, whereas the remaining chloride anions are apically bound to Cu(II) cations. In contrast to the complex 1, the square-pyramidal geometry of the both Cu(II) centers is strongly distorted. The magnetic study revealed that antiferromagnetic interactions in the complex 2 are much stronger than in the complex 1, which was corresponded with magneto-structural examination. Thin layers of the studied Cu(II) complexes were deposited on Si(111) by the spin coating method and studied by scanning electron microscopy (SEM/EDS), atomic force microscopy (AFM), and fluorescence spectroscopy. The Cu(II) complexes and their thin layers exhibited fluorescence between 489-509 nm and 460-464 nm for the compounds and the layers, respectively. Additionally, DFT calculations were performed to explain the structures and electronic spectral properties of the ligands.

Zinc Phthalocyanine Photochemistry by Raman Imaging, Fluorescence Spectroscopy and Femtosecond Spectroscopy in Normal and Cancerous Human Colon Tissues and Single Cells

Photodynamic therapy is a clinically approved alternative method for cancer treatment in which a combination of nontoxic drugs known as photosensitizers and oxygen is used. Despite intensive investigations and encouraging results, zinc phthalocyanines (ZnPcs) have not yet been approved as photosensitizers for clinical use. Label-free Raman imaging of nonfixed and unstained normal and cancerous colon human tissues and normal human CCD18-Co and cancerous CaCo-2 cell lines, without and after adding ZnPcS4 photosensitizer, was analyzed. The biochemical composition of normal and cancerous colon tissues and colon cells without and after adding ZnPcS4 at the subcellular level was determined. Analyzing the fluorescence/Raman signals of ZnPcS4, we found that in normal human colon tissue samples, in contrast to cancerous ones, there is a lower affinity to ZnPcS4 phthalocyanine. Moreover, a higher concentration in cancerous tissue was concomitant with a blue shift of the maximum peak position specific for the photosensitizer from 691-695 nm to 689 nm. Simultaneously for both types of samples, the signal was observed in the monomer region, confirming the excellent properties of ZnPcS4 for photo therapy (PDT). For colon cell experiments with a lower concentration of ZnPcS4 photosensitizer, c = 1 × 10-6 M, the phthalocyanine was localized in mitochondria/lipid structures; for a higher concentration, c = 9 × 10-6 M, localization inside the nucleus was predominant. Based on time-resolved experiments, we found that ZnPcS4 in the presence of biological interfaces features longer excited-state lifetime photosensitizers compared to the aqueous solution and bare ZnPcS4 film on CaF2 substrate, which is beneficial for application in PDT.

Sorafenib-Conjugated Zinc Phthalocyanine Based Nanocapsule for Trimodal Therapy in an Orthotopic Hepatocellular Carcinoma Xenograft Mouse Model

Sorafenib, a multitargeted kinase inhibitor, has been reported to elicit a limited therapeutic effect in hepatocellular carcinoma (HCC). Currently, phototherapy, including photodynamic therapy (PDT) and photothermal therapy (PTT), is emerging as a powerful modality for cancer therapy. However, few studies have been reported the effectiveness of the combination of sorafenib with PDT and PTT in HCC. Herein, we designed and synthesized bovine serum albumin (BSA)-coated zinc phthalocyanine (ZnPc) and sorafenib (SFB) nanoparticle (ZnPc/SFB@BSA). The obtained ZnPc/SFB@BSA was able to trigger PDT, PTT, and chemotherapy. After irradiation by a 730 nm light, ZnPc/SFB@BSA significantly suppressed HCC cell proliferation and metastasis while promoted cell apoptosis in vitro. Furthermore, intravenous injection of ZnPc/SFB@BSA led to dramatically reduced tumor growth in an orthotopic xenograft HCC model. More importantly, ZnPc/SFB@BSA presented low toxicity and adequate blood compatibility. Therefore, a combination of ZnPc with sorafenib via BSA-assembled nanoparticle can markedly suppress HCC growth, representing a promising strategy for HCC patients.

Heteroleptic complexes of cocaine/TMEDA with some f block metals: Synthesis, DFT studies, spectral, thermal, cytotoxicity and antimetastatic properties

A series of new three heteroleptic complexes of the general formula [Ln(Cn)(TMEDA)Cl(OH₂)]·2Cl·xH₂O, (where Ln = La(III), Er(III) and Yb(III), Cn = cocaine and TMEDA = N,N,N',N'-tetramethylethylenediamine) were synthesized, structurally characterized by elemental analysis, spectroscopic methods, molar conductivity and mass spectrometry. Thermal properties of the synthesized complexes and their kinetic thermodynamic parameters were studied. Theoretical calculations including geometry optimization, electronic structure and electronic and thermal energies were carried out using DFT and TD-DFT calculations at B3LYP/LANL2DZ level of theory and the different quantum chemical parameters were calculated. The in vitro antiproliferative activity of the newly synthesized complexes was assessed by MTT assay on MCF-7 and HepG-2 cancer cell lines. Yb(III) complex showed promising cytotoxic activity comparable to that of cisplatin on both cell lines with minimum effect on human normal cells. Further molecular mechanistic investigations showed that Yb(III) complex is an apoptotic inducer as it raises the caspase-3 and caspase-9 cellular level in the MCF-7 cell line. Furthermore, it showed an elevating effect on the level of the tumor suppressor nuclear proteins P21 and P27 concentrations in MCF-7 cells. Moreover, Yb(III) complex hindered the cellular scavenger system of the reactive oxygen species through reducing the glutathione peroxidase (GPx) cellular level imperiling MCF-7 cells by unmanageable oxidative stress. In addition to its cytotoxic effect, Yb(III) complex showed antimetastatic properties as it decreased the cellular levels of matrix metalloproteinases MMP-3 and MMP-9. These results showed that the Yb(III) complex is a promising cytotoxic metal-based agent that exerts its action through various molecular mechanisms with minimum effects on normal cells and with additional antimetastatic properties.

Luteolin protects against lead acetate-induced nephrotoxicity through antioxidant, anti-inflammatory, anti-apoptotic, and Nrf2/HO-1 signaling pathways

Lead (Pb) is one of the most common heavy metal pollutants affecting living organisms. It induces nephrotoxicity with significant alterations in renal structure and function. Luteolin (LUT) a flavonoid present in various plant products is well known for exhibiting numerous pharmacological properties. We evaluated the protective efficacy of LUT against Pb-induced renal injury in male Wistar rats. Four experimental groups: control, LUT (50 mg/kg, orally), PbAc (20 mg/kg, i.p.), LUT + PbAc (at the aforementioned doses) were maintained for 7 days. PbAc administration significantly increased renal Pb accumulation, urea, and creatinine levels in serum, and induced renal histological alterations. Additionally, compared to the control rats, PbAc-treated rats exhibited significantly low levels of antioxidant enzyme activity and expression (SOD, CAT, GPx and GR), as well as high MDA levels. Moreover, PbAc exposure downregulated Nfe212 and Homx1 mRNA expression and significantly increased inflammatory marker (TNF-α, IL-1β and NO) levels in renal tissue. PbAc significantly upregulated the synthesis of apoptotic related proteins and downregulated antiapoptotic protein expression. Notably, LUT pretreatment of PbAc-treated rats provided significant nephroprotection and reversed the alterations in the abovementioned parameters. In conclusion, LUT provided significant protection against PbAc intoxication via antioxidant, anti-inflammatory, and anti-apoptotic activities by activating the Nrf2/ARE signaling pathway.

High-efficiency Ni2+-NTA/PAA magnetic beads with specific separation on His-tagged protein

To effective capture and universal enrichment of His-tagged protein, polyacrylic acid (PAA) brushes were used to encapsulate Fe3O4 nanoparticles, connect NTA, and Ni2+ to prepare magnetic beads. These materials provide many advantages, such as excellent stability, tuneable particle size, and a surface for further functionalisation with biomolecules. His-tagged green fluorescence protein (GFP) was separated efficiently, and the binding capacity of Fe3O4/MPS@PAA/NTA-Ni2+ was 93.4 mg/g. Compared with High-Affinity Ni-NTA Resin and Ni-NTA Magnetic Agarose Beads, Fe3O4/MPS@PAA/NTA-Ni2+ nanocomposites exhibited higher separation efficiency and binding capacity towards His-tagged GFP. Moreover, the selectivity and recyclability of them for the target proteins were maintained well after six cycles. This study would widen the application of PAA in constructing multifunctional nanocomposites for biomedical fields.

Understanding the interaction between α-1-acid glycoprotein (AGP) and potential Cu/Zn metallo-drugs of benzimidazole derived organic motifs: A multi-spectroscopic and molecular docking study

Drug-binding and interactions with plasma proteins strongly affect their efficiency of delivery, hence considered as a key factor in determining the overall pharmacological action. Alpha-1-acid glycoprotein (AGP), a second most abundant plasma protein in blood circulation, has unique drug binding ability and involved in the transportation of various compounds. Here, we have investigated the mechanism of interaction between AGP and potential Cu/Zn metallo-drugs of benzimidazole derived organic motifs (CuL₂ and ZnL₂, where L is Schiff base ligand) by applying integrated spectroscopic, biophysical techniques and computational molecular docking analyses. We found that both the metallo-drugs (CuL₂ and ZnL₂) were bound at the central cavity of AGP interacting with the residues of lobe I, lobe II as well as lobe III. The binding of metallo-drugs to AGP occurs in 1:1 M ratios. Hydrogen bonding, electrostatic and hydrophobic interactions played a significant role in stabilizing the AGP-metallo-drug complexes. Binding affinities of both the metallo-drugs towards AGP at 298 K were of the order of 10⁴-10⁵ M^-1, corresponding to Gibbs free energy of stabilization of approximately -5.50 to -6.62 kcal mol^-1. Furthermore, the spectroscopic investigation by circular dichroism and synchronous fluorescence analyses suggest conformational changes in AGP upon the binding of metallic compounds.

Case Report: Primary Hypothyroidism Associated With Lutetium 177-DOTATATE Therapy for Metastatic Paraganglioma

BACKGROUND

Lutetium 177 (¹⁷⁷Lu) - DOTATATE is a form of peptide receptor radionuclide therapy (PRRT) utilized in the treatment of neuroendocrine tumors. Data on ¹⁷⁷Lu-DOTATATE-induced thyroid dysfunction is limited.

CASE DESCRIPTION

A 29-year-old male with SDHB positive metastatic paraganglioma enrolled under the ¹⁷⁷Lu-DOTATATE trial (NCT03206060) underwent thyroid function test (TFT) evaluation comprised of thyroid stimulating hormone (TSH) and free thyroxine (FT4) immunoassay measurements per protocol prior to ¹⁷⁷Lu-DOTATATE therapy. The TSH was suppressed [<0.01 µIU/ml (0.27-4.2 µIU/ml)], and FT4 was normal [1.3 ng/dl (0.9-1.7 ng/dl)]. The TSH receptor antibody and thyroid stimulating immunoglobulin index were undetectable [<1 IU/L (≤1.75 IU/L), and <1 (≤1.3) respectively], while the anti-thyroid peroxidase (anti-TPO) and anti-thyroglobulin (anti-Tg) antibodies were elevated [605 IU/ml (0.0-34.9 IU/ml), and 178 IU/ml (0.0-40.0 IU/ml) respectively]. Mass spectrometry on a stored (-80°C) plasma sample obtained one-month pre-PRRT revealed elevated total triiodothyronine (TT3) [235 ng/dl (65-193 ng/dl)] and FT4 [3.9 ng/dl (1.2-2.9 ng/dl)] levels. The patient was diagnosed with Hashimoto's thyrotoxicosis. However, the patient was asymptomatic. One month after the first dose of 200mCi ¹⁷⁷Lu-DOTATATE, the patient noted fatigue and a 2.6 Kg weight gain. The TSH (73.04 µIU/ml), anti-TPO antibodies (>1,000 IU/ml), and anti-Tg antibodies (668 IU/ml) had substantially increased, with reductions in FT4 (0.3 ng/dl) and TT3 [54 ng/dl (87-169 ng/dl)]. Diagnostic gallium 68 - DOTATATE positron emission tomography-computed tomography performed prior to ¹⁷⁷Lu-DOTATATE treatment revealed diffuse thyroid uptake. Post-therapy single-photon emission computed tomography also revealed diffuse uptake of ¹⁷⁷Lu-DOTATATE in the thyroid gland. Levothyroxine therapy was initiated, and the patient's symptoms resolved.

SUMMARY

We report, for the first time, a patient with asymptomatic primary hyperthyroidism who rapidly developed symptomatic primary hypothyroidism 1 month after ¹⁷⁷Lu-DOTATATE therapy, accompanied by marked changes in TFTs and thyroid auto-antibody titers, with functional imaging evidence of diffuse uptake of ¹⁷⁷Lu-DOTATATE in the thyroid gland.

CONCLUSIONS

Thyroid dysfunction can be associated with PRRT. Thyroid uptake patterns on pre-treatment diagnostic somatostatin analog scans might predict individual susceptibility to PRRT-associated TFT disruption. Therefore, periodic evaluation of TFTs should be considered in patients receiving PRRT.

Effects of zinc methionine supplementation on laying performance, zinc status, intestinal morphology, and expressions of zinc transporters' mRNA in laying hens

BACKGROUND

This study was conducted to investigate effects of dietary zinc methionine (Zn-Met) supplementation on laying performance, zinc (Zn) status, intestinal morphology, and Zn transporters in laying hens compared with zinc sulfate (ZnSO₄ ). A total of 384 Hyline Grey laying hens (38 weeks old) with similar performance (1.42 ± 0.07 kg) were randomly allotted to four dietary treatments and fed with a basal diet (control) or the basal diet supplemented with Zn, either as Zn-Met at 40 and 80 mg Zn/kilogram diet or as ZnSO₄ at 80 mg Zn/kilogram diet, for 10 weeks.

RESULTS

There was no difference in egg weight, egg production, feed intake, and feed conversation ratio among all groups (P > 0.05). Compared with the control, Zn contents were increased (P < 0.05) in the liver, duodenum, and jejunum of laying hens fed diets supplemented with different Zn sources. There was no difference (P > 0.05) in Zn contents in liver, duodenum, and jejunum between diets supplemented with Zn-Met or ZnSO₄ at 80 mg Zn/kilogram diet. Compared with the control and the ZnSO₄ group (80 mg Zn/kilogram diet), supplementation with Zn-Met of 80 mg Zn/kilogram diet increased (P < 0.05) villus height, villus area, and villus height/crypt depth ratio but reduced (P < 0.05) crypt depth in jejunum. Expression of metallothionein messenger RNA of jejunum in the group fed a diet containing Zn-Met (80 mg Zn/kilogram diet) was higher (P < 0.05) than that in the control.

CONCLUSION

These results indicated that Zn-Met has positive effects on the Zn status of liver, duodenum, and jejunum, intestinal morphology, and metallothionein messenger RNA expression in jejunum of laying hens compared with ZnSO₄ . © 2019 Society of Chemical Industry.

The Clinical Impact of [68 Ga]-DOTATATE PET/CT for the Diagnosis and Management of Ectopic Adrenocorticotropic Hormone - Secreting Tumours

OBJECTIVES

Localization of ectopic ACTH-secreting tumours causing Cushing syndrome (ECS) is essential for clinical management, yet often difficult. [⁶⁸ Ga]-DOTATATE PET/CT ([⁶⁸ Ga]-DOTA-(Tyr³ )-octreotate)] is an FDA-approved high-resolution diagnostic tool for imaging neuroendocrine tumours. Data on the clinical utility of [⁶⁸ Ga]-DOTATATE in patients with ECS, however, are scarce. The objectives of this study were to determine the efficacy for ECS localization and the clinical benefit of [⁶⁸ Ga]-DOTATATE imaging.

METHOD

We conducted a retrospective review of all cases with ECS evaluated with [⁶⁸ Ga]-DOTATATE from November 2016 through October 2018 at three referral centres. The clinical benefit of [⁶⁸ Ga]-DOTATATE was based on detection of new tumours and resultant changes in management.

RESULTS

Over the study period, 28 patients with ECS underwent [⁶⁸ Ga]-DOTATATE: 17 for identification of the primary tumour and 11 during follow-up. [⁶⁸ Ga]-DOTATATE identified the suspected primary ECS in 11/17 patients (65%). Of these, nine patients underwent surgery: eight with confirmed ECS (5 bronchial, 1 thymic, 1 pancreatic and 1 metastatic neuroendocrine tumour of unknown primary origin) and one patient with a false-positive scan (adrenal gland). Of the 11 patients with ECS who underwent [⁶⁸ Ga]-DOTATATE evaluation during follow-up, the study led to changes in clinical management in 7/11 (64%) patients.

CONCLUSIONS

[⁶⁸ Ga]-DOTATATE is sensitive in detecting primary and metastatic ECS, often identifies occult tumours after conventional imaging, and impacts clinical care in the majority of patients.

Effects of Dietary Organic, Inorganic, and Nanoparticulate Zinc on Rainbow Trout, Oncorhynchus mykiss Larvae

The present study was conducted to investigate the effects of different dietary zinc sources on growth performance, survival, and body composition of larval rainbow trout, Oncorhynchus mykiss. A total of 3240 larvae with an average weight of 82.3 ± 11.6 mg were randomly divided into four groups by three replicates and were fed for 70 days. Organic zinc (Zn-proteinate, Bioplex Zn®), mineral zinc (ZnSO₄), and nanoparticulate zinc (ZnO-NPs) were each added to the basal diet at 50-mg/kg diet. In all of the zinc-supplemented groups, final body weight (FBW) and weight gain (WG) increased significantly (P < 0.05) compared to the control at the termination of the feeding trial. There was no significant difference in specific growth rate (SGR) in experimental groups. Fish fed with mineral and nanoparticulate zinc, respectively, demonstrated the highest and lowest survival rates (P < 0.05) as compared to other experimental diets. Feed conversion ratio (FCR) significantly decreased (P < 0.05) in groups fed with organic and mineral zinc. There were no significant differences in protein, lipid, moisture, and ash content among fish fed the experimental diets. Fish fed mineral zinc showed the highest (P < 0.05) zinc content in the whole body than the other groups. The data of the present study confirm positive effects of the use of 50 mg kg^-1 of zinc sources in early diet to enhance growth performance of rainbow trout larvae.

Sonochemical synthesis of a nanodandelion tin(IV) complex with carbacylamidophosphate ligand as anti-Alzheimer agent: Molecular docking study

The dandelion-shaped nanostructure of an organotin complex with formula Sn(CH₃)₂Cl₂}NC₅H₄C(O)NHP(O)[NHC₆H₁₁]₂}₂ (C₁) was synthesized by means of a sonochemical method. Nano-structures were characterized by elemental analysis, NMR, SEM-EDS, XRD, UV-Vis, and FT-IR spectroscopy. The thermal stability of the complex C₁ has been studied by thermal gravimetric analysis (TGA), and compared to the bulk form (C₂). Both the morphology and the size of the ultrasound-assisted synthesized organotin complex have been investigated using scanning electron microscopy (SEM) by changing such parameters as the concentration of initial reactants and the sonication frequency. Two different forms of the organotin complex (C₁, C₂) and the corresponding ligand (L) were evaluated by a modified Ellman's method on acetyl- and butyrylcholinesterase enzymes. Nanodendalion C₁ and ligand L showed the best activity against AChE and BChE, respectively, with the IC₅₀ values being 326.59 μg/ml and 426.68 μg/ml. Further, Lineweaver Burk plots indicated that these compounds are mixed inhibitors. The synthesized compounds and cholinesterase enzymes were simulated by molecular docking for more details concerning the conformation and the orientations of these compounds in the active site of the receptor.

Tailoring pore structures with optimal mesopores to remarkably promote DNA adsorption guiding the growth of active Mn3(PO4)2 toward sensitive superoxide biomimetic enzyme sensors

The great challenge in preparing a biomimetic enzyme sensor is to have sensitivity and selectivity equal to or better than its corresponding biological sensor. Porous electrodes possess a large surface area and are often used to greatly improve the sensor sensitivity. However, how to tailor the pore structure, especially the pore size distribution to further improve the sensitivity and selectivity of a biomimetic sensor, has not been investigated yet. The superoxide anion (O2˙-) plays essential roles in various biological processes and is of importance in clinical diagnosis and life science research. It is generally detected by the superoxide dismutase enzyme. Herein, we delicately tailor the pore structure of carbon nanofibers (CNFs) by pyrolysis to obtain an optimal mesopore structure for strong adsorption of DNA, followed by guiding the growth of Mn3(PO4)2 as a biomimetic enzyme toward highly sensitive detection of O2˙-. The Mn3(PO4)2-DNA/CNF sensor achieves the best sensitivity among the reported O2˙- sensors while possessing good selectivity. The enhancement mechanism is also investigated, indicating that the mesopore ratio of CNFs plays an essential role in the high sensitivity and selectivity due to their strong adsorption of DNA for guiding the growth of a large amount of uniform sensing components, Mn3(PO4)2, toward high sensitivity and selectivity. The biomimetic sensor was further used to in situ monitor O2˙- released from human keratinocyte cells and human malignant melanoma cells under drug stimulation, showing high sensitivity to real-time quantitative detection of O2˙-. This work provides a highly sensitive in situ real-time biomimetic O2˙- sensor for applications in biological research and diagnosis, while shedding light on the enhancement mechanism of the pore structure, especially the pore size distribution of a porous electrode for high performance sensing processes.