Design and development of 6-hydrazinonicotinyl-fatty acid-mimetic 99mTc-complex as a potential myocardial imaging agent

Abstract The goal of this work is to identify new fatty acid-mimetic 99mTc-complexes to be used as myocardial imaging agents that allow studying heart abnormalities in high-risk patients. In this sense, we designed a fatty acid-mimetic substructure including an amide moiety that, among other properties, could improve myocardial residence time. A diamide with a chain length of 15 atoms and porting a 6-hydrazinonicotinyl (HYNIC) chelator, and an analog with a short carbon-chain, were prepared with convergent organic synthetic procedures and radiolabeled with 99mTc using tricine as the sole coligand. The in vivo proofs of concept were performed using healthy mice. The new 99mTc-complexes were obtained with adequate radiochemical purity. The lipophilicities were in agreement with the length of the chains. While both 99mTc-complexes showed uptake in the myocardial muscle, the designed radiopharmaceutical with the longest chain length had preferential target-uptake and target-retention compared to other complexes described in the bibliography. Further studies, involving imaging assays, synthetic modifications, and assay of new coligands for 99mTc-HYNIC complexes, are currently ongoing.

Disfunción tiroidea por I131-Metayodo Benzilguanidina en pacientes con neuroblastoma / Thyroid dysfunction due to 131I-metaiodobenzylguanidine in patients with neuroblastoma

Resumen: Introducción: El tratamiento del neuroblastoma en estadios avanzados incluye quimioterapia, cirugía y terapia con I131-Metayodo benzilguanidina (I131-MIBG). La disfunción tiroidea se reporta entre 12 y 85% a pesar de la protección tiroidea. Objetivo: Identificar la frecuencia de disfunción tiroidea en casos de neu roblastoma tratados con I131-MIBG. Pacientes y Método: Estudio transversal. Se incluyeron todos los casos con diagnóstico de neuroblastoma que recibieron I131-MIBG en el periodo de 2002-2015, a los cuales se les realizó antropometría completa, perfil de tiroides: hormona estimulante de tiroides (TSH), Triyodotironina total y libre (T3t y T3l), tiroxina total y libre (T4t, T4l), y anticuerpos antitiroglobulina y antiperoxidasa. Resultados: Se identificaron un total de 27 pacientes; once fallecieron (40%). De los 16 casos sobrevivientes, 9 (56%) presentaron disfunción tiroidea: 2 (13%) casos con hipotiroidismo subclínico y 7 (44%) casos con hipotiroidismo clínico (3 casos por retraso en el desa rrollo psicomotor y 4 por desaceleración del crecimiento). Los pacientes presentaron manifestaciones clínicas a los 16,1 meses (1,2-66,3 meses) de recibir el radiofármaco a una dosis acumulada de 142 mCi (96-391.5 mCi). No se logró evidenciar diferencias en la edad al diagnóstico, la edad al inicio del tratamiento con el I131-MIBG, la dosis acumulada del I131-MIBG y el tiempo trascurrido entre la dosis y el perfil tiroideo entre los casos con o sin disfunción tiroidea. Conclusiones: El 56% de los pacientes con neuroblastoma presentaron disfunción tiroidea. La mayoría de los casos con hipotiroidismo fue ron referidos cuando los datos de disfunción tiroidea eran clínicamente evidentes. Se propone en esta poblacion realizar perfil tiroideo semestral y valoración anual por un endocrinólogo pediatra durante los primeros 5 años posteriores al diagnóstico oncológico.

Abstract: Introduction: The treatment of advanced neuroblastoma includes chemotherapy, surgery, and radiotherapy with 131-I-Metaiodobenzylguanidine (131-I-MIBG). Despite strategies to protect thyroid function, its dysfunction is reported between 12 and 85%. Objective: To identify the frequency of thyroid dys function in cases of neuroblastoma treated with 131-I-MIBG. Patients and Method: Cross-sectional study. We included all the cases with neuroblastoma treated with 131-I-MIBG between 2002 and 2015, with complete somatometry, and complete thyroid profile (TSH, free and total T3 and T4, and anti-thyroglobulin and antiperoxidase antibodies). Results: 27 patients were identified out of which eleven died (40%). Out of the 16 surviving cases, 9 (56%) presented thyroid dysfunction: 2 (13%) cases with subclinical hypothyroidism and 7 (44%) cases with clinical hypothyroidism (3 cases due to psychomotor developmental delay and 4 due to growth deceleration). The patients presented cli nical manifestations at 16.1 months (1.2-66.3 months) after receiving the radiopharmaceutical at acumulative dose of 142 mCi (96-391.5 mCi). No differences were found in the age at diagnosis, age at the start of treatment with 131-I-MIBG, the cumulative dose of 131-I-MIBG, and the time elapsed between the dose and the thyroid profile among the cases with or without thyroid dysfunction. Con clusions: 56% of patients with neuroblastoma had thyroid dysfunction. Most of the cases with hypothyroidism were referred when thyroid dysfunction was clinically evident. A thyroid profile should be performed every 6 months, along with an annual endocrinological evaluation during the next 5 years in these patients.

Spinal cord compression after radiolabeled metaiodobenzylguanidine analogue therapy in advanced malignant insulinoma

Malignant insulinomas are frequently diagnosed at a late stage. Medical management is necessary to slow progression of the disease and control of hypoglycemic symptoms when cure by surgical treatment is not possible. Multimodal treatment, in these cases, has been used with variable clinical response. We describe a 68-yr-old woman who presented response failure to usual treatment and was alternatively treated with radiolabeled metaiodobenzylguanidine ([131I]-MIBG) analogue therapy with development of neurologic complications. We also present a review of the current role of [131I]-MIBG treatment in insulinomas.

Comparison of the Safety of Seven Iodinated Contrast Media

We aimed to determine the characteristic adverse events (AEs) of iodinated contrast media (IOCM) and to compare the safety profiles of different IOCM. This study used the database of AEs reports submitted by healthcare professionals from 15 Regional Pharmacovigilance Centers between June 24, 2009 and December 31, 2010 in Korea. All reports of IOCM, including iopromide, iohexol, iopamidol, iomeprol, ioversol, iobitridol and iodixanol, were analyzed. Safety profiles were compared between different IOCM at the system organ level using the proportional reporting ratio (PRR) and 95% confidence interval (95% CI). Among a total of 48,261 reports, 6,524 (13.5%) reports were related to the use of IOCM. Iopromide (45.5%), iohexol (16.9%), iopamidol (14.3%) and iomeprol (10.3%) were identified as frequently reported media. 'Platelet, bleeding & clotting disorders' (PRR, 29.6; 95%CI, 1.9-472.6) and 'urinary system disorders' (PRR, 22.3; 95% CI, 17.1-29.1) were more frequently reported for iodixanol than the other IOCM. In conclusion, the frequency of AEs by organ class was significantly different between individual media. These differences among different IOCM should be considered when selecting a medium among various IOCM and when monitoring patients during and after its use to ensure optimum usage and patient safety.

Design of a PLC system for automatic I-123 production

Design of the production system for Iodine-123 has begun recently in nuclear research centre of agricultural and medicine [NRCAM]. The production system consists of pipes for xenon gas transfer, equipped with 10 valves, 3 heaters, fluid nitrogen and 2 vacuum pumps. In the first prototype the function of elements was being done manually by an operator. Because dispensing radiopharmaceuticals manually involves receiving radiation dose by operators, therefore, automation is very important step in radiopharmaceutical production. The automatic system for production of Iodine-123 is PLC /135u Siemens, which is designed and installed for the first time in Iran. The PLC was connected to the production system through relays. By programming the CPU of the PLC, start up and control of the production procedure was executed automatically. Automation leads to reduced presence of operator for Iodine-123 production. We were also able to record storage and transfer of materials and minimize risk of error. Automation in production of radiopharmaceutical may lead to reduced radiation dose to personnel and achieved better dispensing precision

Quantitative enzymuria following aorto-renal angiography.

Quantitative estimation of urinary enzymes has been advocated as a more sensitive marker than conventional renal function tests to assess radio-contrast media induced nephrotoxicity. We studied 27 subjects with normal renal functions who underwent abdominal aortography for varied indications. Among these, 8 also required selective renal arteriography and 3 underwent arch aortography in addition. Sodium iothalamate was used as a radio-contrast medium and the average amount injected was 73 ml (45 to 120 ml) per subject. Standard renal function assessment including urinalysis, 24 hour urinary protein excretion, creatinine clearance done both before and after aortography did not show any significant alteration. Urinary excretion of tubular enzymes including leucine aminopeptidase (LAP), alkaline phosphatase (ALP), gamma-glutamyl transpeptidase (GGT) and maltase (MAL) was estimated before and 2, 24 and 48 hours after aortography. All enzymes showed a significant rise at 2 hours. Urinary excretion of LAP, ALP and GGT peaked at 24 hours after aortography without a further change in MAL levels. Enzymuria returned to baseline values 48 hours following the procedure. It is concluded that an increase in the urinary excretion of the brush-border enzymes within 24 hours of contrast media administration may suggest an early nephrotoxicity.