[14C] Radiotracer Studies of the Hydrogenation Reactions Over Supported Platinum Catalysts

The adsorption of acetylene, ethylene and carbon monoxide; the hydrogenation of acetylene and buta-1,3-diene; the effects of sulphur poisoning on the adsorption, and the hydrogenation reactions, have been studied at ambient temperature in a static system using a variety of supported platinum catalysts. The catalysts used were EUROPT-1 (6% Pt/SiO2), EUROPT-3 (0.3% Pt/Al2O3), 0.5% Pt/MoO3, 0.8% Pt/SiO2 and 0.8% Pt/Al2O3. Using the [14-C] radiotracer technique, the shape of acetylene adsorption isotherms over each catalyst showed two distinct adsorption regions, a steep primary region followed (except Pt/MoO3) by a linear secondary region. The Pt/MoO3 catalyst showed a nonlinear secondary region. The adsorption of ethylene also occurred in two distinct stages, but the primary region was less steep than was found with acetylene. The adsorptive capacity of the catalysts for ethylene was approximately one quarter that for acetylene. In contrast, the adsorption isotherms of carbon monoxide showed distinct dissimilarities between catalysts. On EUROPT-1, 0.8% Pt/SiO2 and 0.8% Pt/Al2O3 catalysts, the isotherms displayed different behaviour from that observed with the hydrocarbons in that they showed a prolonged secondary region with a positive gradient. The adsorption isotherm of CO on EUROPT-3 was of a similar shape to the isotherms observed with the hydrocarbons. The Pt/MoO3 catalyst exhibited the expected Langmuir-type CO adsorption isotherm. On steady state catalysts the amount of each adsorbate that can be adsorbed was substantially less than that on freshly reduced catalysts. This has been suggested as being due to the permanently retained hydrocarbon species located at the primary adsorption region. With each catalyst the experimental observations are consistent with the dissociative adsorption of the hydrocarbons on the primary region, whilst the species involved in the actual catalysis process are located on the secondary region and are associatively adsorbed. From the poisoning experiments, evidence has been obtained to show that a surface reconstruction process accompanies the initial adsorption. The results are interpreted in terms of a model involving the migration of metal atoms into the adsorbate ad-layer. The adsorption of acetylene in the presence of gas phase ethylene and vice versa indicates that the adsorption of the two hydrocarbons takes place on the same adsorption sites with acetylene being more strongly adsorbed than ethylene. However, during the hydrogenation of acetylene, hydrogen was found to create sites which were active for the non-competitive adsorption of ethylene. IR evidence has been obtained for the formation of an ethylidyne (-C-CH3) species upon the exposure of a freshly reduced EUROPT-1 to C2H2 or C2H4, while bands characteristic of hydrocarbon polymeric species were detected with C2H2/H2 deactivated catalysts. On each catalyst, the adsorbed carbon monoxide was found to exist in the linear form. From the experimental observations regarding the hydrogenation of acetylene in the presence of various pressures of [14-C] -ethylene and determination of the kinetics and product distribution, it has been established that the major route to ethane formation is via a route involving direct hydrogenation of acetylene, rather than via ethylene as an intermediate. The results have been interpreted in terms of the presence of separate surface sites for the hydrogenation of acetylene to ethylene, the hydrogenation of acetylene to ethane and for the hydrogenation of ethylene to ethane. From the kinetics and variations of the product compositions with the experimental variables for buta-1,3-diene hydrogenation, it has been proposed that, whilst 1:2 addition of hydrogen to the buta-1,3-diene was responsible for but-l-ene formation, 1:4 addition of hydrogen to buta-1,3-diene, rather than the isomerisation of but-l-ene, was responsible for the production of trans-but-2-ene and cis-but-2-ene

Active Lumbar Spondylodiscitis on [68Ga]Ga-PSMA-11 PET/CT Mimicking Bone Metastasis

We report a [68Ga]Ga-PSMA-11 positron emission tomography/computed tomography (PET/CT) scan of a 71-year-old man with metastatic castration-resistant prostate cancer (mCRPC) and concomitant active lumbar spondylodiscitis, both PSMA-positive on a PET/CT scan. This interesting image should advise colleagues to consider spondylodiscitis as a differential diagnosis of PSMA-positive findings in the spine, particularly if intervertebral space and soft tissue are involved

Systemic Mastocytosis Treatment with Midostaurin: [18F]FDG PET/CT as a Potential Monitoring Tool for Therapy Outcome

We report the case of a 68-year-old patient with diagnosed systemic mastocytosis and histopathologically confirmed manifestations in the stomach and intestinal tract who underwent 18FFluorodeoxyglucose ([18F]FDG) positron-emission tomography/computed tomography (PET/CT) pre- and post-6-month therapy with midostaurin, an established tyrosine kinase inhibitor. Posttherapeutic [18F]FDG PET/CT showed decreased multifocal tracer uptake in the known lesions in the gastrointestinal tract, which was consistent with relief of the patient’s symptoms and decrease in serum tryptase level. [18F]FDG PET/CT may thus be considered a potential method for monitoring the outcome of midostaurin therapy in systemic mastocytosis

Histologically Confirmed Testicular Metastasis Revealed by [89Zr]Zr-PSMA-617 PET/CT in a Patient with Biochemical Recurrence of Prostate Cancer and Negative Conventional PSMA PET/CT Imaging

We present an interesting image of a testicular metastasis from prostate cancer revealed by [ 89Zr]Zr-PSMA-617 PET/CT imaging in a 70-year-old man with biochemical recurrence and negative conventional [68Ga]Ga-PSMA-11 PET/CT imaging. This case should encourage the consideration of [ 89Zr]Zr-PSMA-617 PET/CT if conventional PSMA PET/CT imaging had failed to localize biochemical recurrence, and may remind colleagues of this rare but potential metastatic localization in this setting

Striatal dopamine transporters and cognitive function in Parkinson's disease

Background Idiopathic Parkinson’s disease (PD) is characterized by clinical motor symptoms including hypokinesia, rigidity and tremor. In addition to the movement disorder, cognitive deficits are commonly described. In the present study, we applied FP‐CIT SPECT to investigate the impact of nigrostriatal dopaminergic degeneration on cognitive function in PD patients. Methods Fifty‐four PD patients underwent [123I]FP‐CIT SPECT and CERAD (Consortium to Establish a Registry for Alzheimer’s Disease) testing. FP‐CIT SPECT visualized the density of presynaptic dopamine transporters in both striata, each subdivided into a limbic, executive and sensorimotor subregion according to the atlas of Tziortzi et al (Cereb Cortex 24, 2014, 1165). CERAD testing quantified cognitive function. Results In the CERAD testing, PD patients exhibited deficits in the domains of semantic memory, attention, visuospatial function, non‐verbal memory and executive function. After correction for multiple testing, the performance of the subtests Figure Recall and Trail‐Making Test A correlated significantly with FP‐CIT uptake into the ipsilateral executive subregion. The performance of the subtest Figure Saving correlated significantly with FP‐CIT uptake into the contralateral executive subregion. Conclusions The significant correlation between cognitive function and density of nigrostriatal dopamine transporters, as assessed by FP‐CIT SPECT, indicate that striatal dopaminergic pathways—primarily the executive striatal subregion—are relevant to cognitive processing in PD

Strongly Radioiodine-Positive Pancreatic Adenocarcinoma Mimicking Metastasis of Differentiated Thyroid Cancer

We present an interesting image of a strikingly intense radioiodine accumulation of a histologically proven pancreatic adenocarcinoma mimicking metastasis of differentiated thyroid cancer in a 63-year-old woman with recurrence of papillary thyroid carcinoma undergoing radioiodine therapy. This interesting image should draw attention to considering pancreatic adenocarcinoma in radioiodine-positive pancreatic lesions

PSMA-Positive Follicular Thyroid Carcinoma Incidentally Detected by [68Ga]Ga-PSMA-11 PET/CT: Correlation with Immunohistology Confirms Neovascular PSMA-Expression

We present an interesting image of an intense PSMA-positive follicular thyroid carci noma incidentally detected by [68Ga]Ga-PSMA-11 PET/CT in a 76-year-old man with biochemical recurrence of prostate cancer. Immunohistochemical staining demonstrated PSMA expression in the endothelial cells of tumor tissue. This interesting image should remind colleagues to consider malignant thyroid neoplasia in PSMA-positive thyroid lesions

Molecular imaging and biochemical response assessment after a single cycle of [225Ac]Ac-PSMA-617/[177Lu]Lu-PSMA-617 tandem therapy in mCRPC patients who have progressed on [177Lu]Lu-PSMA-617 monotherapy

Rationale: Despite the promising results of prostate-specific membrane antigen (PSMA)-targeted 177Lu radioligand therapy in metastatic castration-resistant prostate carcinoma (mCRPC), some patients do not respond and other patients with initially good response develop resistance to this treatment. In this study, we investigated molecular imaging and biochemical responses after a single cycle of [225Ac]Ac-PSMA-617/[177Lu]Lu-PSMA-617 tandem therapy in patients who had progressed on [177Lu]Lu-PSMA-617 monotherapy. Methods: Seventeen patients with mCRPC were included in a retrospective, monocenter study. Molecular imaging-based response was assessed by modified PERCIST criteria using the whole-body total lesion PSMA (TLP) and molecular tumour volume (MTV) derived from [68Ga]Ga-PSMA-11 PET/CT. Biochemical response was evaluated according to PCWG3 criteria using the prostate-specific antigen (PSA) serum value. Concordance and correlation statistics as well as survival analyses were performed. Results: Based on the molecular imaging-based response assessment, 5 (29.4%) patients showed partial remission and 7 (41.2%) had stable disease. The remaining 5 (29.4%) patients had further progression, four with an increase in TLP/MTV of >30% and one with stable TLP/MTV but appearance of new metastases. Based on the biochemical response assessment, 5 (29.4%), 8 (47.1%), and 4 (23.5%) patients showed partial remission, stable disease, and progressive disease, respectively. A comparison of the response assessment methods showed a concordance of 100% (17/17) between TLP and MTV and 70.6% (12/17) between TLP/MTV and PSA. Patients with partial remission, independently assessed by each method, had better overall survival (OS) than patients with either stable or progressive disease. The difference in OS was statistically significant for the molecular imaging response assessment (median OS not reached vs. 8.3 m, p = 0.044), but not for the biochemical response assessment (median OS 18.1 m vs. 9.4 m, p = 0.468). Conclusion: Based on both assessment methods, [225Ac]Ac-PSMA-617/[177Lu]Lu-PSMA-617 tandem therapy is an effective treatment for the highly challenging cohort of patients with mCRPC who have progressed on [177Lu]Lu-PSMA-617 monotherapy. Molecular imaging response and biochemical PSA response were mostly concordant, though a considerable number of cases (29.4%) were discordant. Molecular imaging response reflecting the change in total viable tumour burden appears to be superior to PSA change in estimating survival outcome after tandem therapy

Does PRRT with standard activities of 177Lu-octreotate really achieve relevant somatostatin receptor saturation in target tumor lesions?: insights from intra-therapeutic receptor imaging in patients with metastatic gastroenteropancreatic neuroendocrine tumors

Twenty plantain crop fields were sampled to identify Meloidogyne spp. in Tierralta and Valencia municipalities. Ten soil and root samples per field were taken to obtain the nematodes. Meloidogyne species classification was based on the perineal pattern of the female, shape of the stylet in females, males and juveniles (J2), and shape and number of rings on the cephalic region in J2 and males. Stylet length and dorsal oesophageal gland (DOG) on males, females and J2, body length, tail and hyaline tail region in J2 were measured to identify the specie of root-knot nematode. Meloidogyne spp. were found in 80% of the fields in Valencia, and 60% of the field in Tierralta. M. incognita and M. arenaria were detected. M. incognita was the most frequent species throughout the sampled area. Mixtures of both species were found in both municipalities. This is the first report of mixed M. incognita and M. arenaria associated to plantain crop in Colombia.Veinte cultivos de plátano fueron muestreados en los municipios de Tierralta y Valencia para identificar las especies de Meloidogyne asociadas a este cultivo. Diez muestras de suelos y raíces fueron colectadas en cada de los lotes, las cuales fueron usadas para la obtención de los nemátodos. La clasificación de las especies se basó en las características morfológicas (patrón perineal de las hembras, forma del estilete de hembras, machos y juveniles (J2); forma y número de anillos de la región cefálica de J2 y machos) y morfométricas (longitud del estilete y la distancia de la base del estilete a la desembocadura de la glándula dorsal (D.G.O) de hembras, machos y J2; longitud del cuerpo, la cola y la región hialina de los J2. En el 80% de las fincas en Valencia se detectó la presencia de estos nematodos, mientras que el 60% de los predios en Tierralta fueron positivos para los mismos. Las especies encontradas fueron Meloidogyne incognita y M. arenaria. De estas, M. incognita fue la más frecuente detectada en la zona productora de plátano en los dos municipios. Mezcla de especies fueron detectadas en ambos municipios. Se reporta por primera vez en Colombia las especies M. incognita y M. arenaria, así como la mezcla de las mismas asociadas al cultivo de plátano

Addition of Standard Enzalutamide Medication Shows Synergistic Effects on Response to [177Lu]Lu-PSMA-617 Radioligand Therapy in mCRPC Patients with Imminent Treatment Failure—Preliminary Evidence of Pilot Experience

Well-received strong efficacy of prostate-specific membrane antigen (PSMA)-targeted radioligand therapy (RLT) does not prevent patients from either early or eventual disease progression under this treatment. In this study, we investigated co-medication with enzalutamide as a potential re-sensitizer for PSMA-RLT in patients with imminent treatment failure on standard 177Lu-based PSMA-RLT. Ten mCRPC patients who exhibited an insufficient response to conventional [177Lu]Lu PSMA-617 RLT received oral medication of enzalutamide 160 mg/d as an adjunct to continued PSMA RLT. Prostate-specific antigen (PSA) and standard toxicity screening lab work-up were performed to assess the treatment efficacy and safety in these individuals. The mean PSA increase under PSMA-RLT before starting the re-sensitizing procedure was 22.4 ± 26.5%. After the introduction of enzalutamide medication, all patients experienced a PSA decrease, –43.4 ± 20.0% and –48.2 ± 39.0%, after one and two cycles of enzalutamide-augmented PSMA-RLT, respectively. A total of 70% of patients (7/10) experienced partial remission, with a median best PSA response of –62%. Moreover, 5/6 enzalutamide-naïve patients and 2/4 patients who had previously failed enzalutamide exhibited a partial remission. There was no relevant enzalutamide-induced toxicity observed in this small cohort. This pilot experience suggests the synergistic potential of adding enzalutamide to PSMA-RLT derived from the intra-individual comparison of 177Lu-based PSMA-RLT ± enzalutamide