99mTc-bisphosphonate-coated magnetic nanoparticles as potential theranostic nanoagent

Novel theranostic nanoplatform is expected to integrate imaging for guiding and monitoring of the tumor therapy with great therapeutic efficacy and fewer side effects. Here we describe the preparation of a multifunctional ^99mTc-bisphosphonate-coated magnetic nanoparticles (MNPs) based on Fe₃O₄ and coated with two hydrophilic bisphosphonate ligands, i.e., methylene diphosphonate (MDP) and 1-hydroxyethane-1,1- diphosphonate (HEDP). The presence of the bisphosphonates on the MNPs surface, enabled their biocompatibility, colloidal stability and successful binding of the radionuclide. The morphology, size, structure, surface charge and magnetic properties of obtained bisphosphonate-coated Fe₃O₄ MNPs were characterized by transmission electron microscopy, X-ray powder diffraction, dynamic light scattering, laser Doppler electrophoresis, Fourier transform infrared spectroscopy and vibrating sample magnetometer. The specific power absorption values for Fe₃O₄-MDP and Fe₃O₄-HEDP were 113 W/g and 141 W/g, respectively, indicated their heating ability under applied magnetic field. Coated MNPs were radiolabeled with ^99mTc using stannous chloride as the reducing agent in a reproducible high yield (95% for Fe₃O₄-MDP and 97% for Fe₃O₄-HEDP MNPs) and were remained stable in saline and human serum for 24 h. Ex vivo biodistribution studies presented significant liver and spleen uptake in healthy Wistar rats after intravenous administration at all examined time points due to the colloidal nature of both ^99mTc-MNPs. Results of scintigraphy studies are in accordance with ex vivo biodistribution studies, demonstrating high in vivo stability of radiolabeled MNPs and therefore results of both methods were proved as accurate information on the biodistribution profile of investigated MNPs. Overall, in vitro and in vivo stability as well as heating ability, indicate that biocompatible radiolabeled bisphosphonate magnetic nanoparticles exhibit promising potential as a theranostic nanoagent.

Hybrid Vision-Fusion system for whole-body scintigraphy

Radioiodine therapy in the treatment of differentiated thyroid carcinoma (DTC) is used in clinical practice for the ablation of thyroid residues and/or destruction of tumour tissue. Whole-body scintigraphy for visualization of the spatial 131I distribution performed by a gamma camera (GC) is a standard procedure in DTC patients after application of radioiodine therapy. A common problem is the precise topographic localization of regions where radioiodine is accumulated even in SPECT imaging. SPECT/CT can provide precise topographic localization of regions where radioiodine is accumulated, but it is often unavailable, especially in developing countries because of the high price of the equipment. In this paper, we present a Vision-Fusion system as an affordable solution for 1) acquiring an optical whole-body image during routine whole-body scintigraphy and 2) fusing gamma and optical images (also available for the auto-contour mode of GC). The estimated prediction error for image registration is 1.84 mm. The validity of fusing was tested by performing simultaneous optical and scintigraphy image acquisition of the bar phantom. The fusion result shows that the fusing process has a slight influence and is lower than the spatial resolution of GC (mean value ± standard deviation: 1.24 ± 0.22 mm). The Vision-Fusion system was used for radioiodine post-therapeutic treatment, and 17 patients were followed (11 women and 6 men, with an average age of 48.18 ± 13.27 years). Visual inspection showed no misregistration. Based on our first clinical experience, we noticed that the Vision-Fusion system could be very useful for improving the diagnostic possibility of whole-body scintigraphy after radioiodine therapy. Additionally, the proposed Vision-Fusion software can be used as an upgrade for any GC to improve localizations of thyroid/tumour tissue.

The influence of Ki-67 proliferation index on Tc-99m-EDDA-HYNIC-TOC somatostatin receptor scintigraphy in patients with carcinoids

The aim of this paper is to determine the influence of Ki-67 proliferation index on somatostatin receptor scintigraphy (SSRS) with Tc-99m-EDDA-HYNIC-TOC (Tc-99m-Tektrotyd) somatostatin analogue in patients with carcinoid tumors. Sixty-one patients (31 female, 30 male; age range: 33-76 years) were examined: 13 patients highly suspected of having a carcinoid, and 48 patients who had undergone the surgical removal of the tumor. Whole body SSRS at 4 h postinjection, spot scintigrams and SPECT of the selected regions were obtained for all patients. Tc-99m-Tektrotyd scintigraphy was classified as true positive in 26 out of 30 and true negative in 24 out of 28 patients. The sensitivity of Tc-99mTc-Tektrotyd scintigraphy was found to be as high as 94.74% in the group of patients with low mitotic index Ki67 (<2%), and it progressively decreased in patients with higher mitotic index (77.78% for Ki67 2-15% and 20% for Ki67% >20%). The likelihood of Tc-99m-Tektrotyd scan being positive when a carcinoid is present was found to be inversely proportional to the value of Ki67 proliferation index. The results showed that Tc-99m-Tektrotyd SSRS is a sensitive method for diagnosing and staging patients with well-differentiated carcinoid tumors. However, in poorly differentiated tumors with high Ki67 proliferation index, additional analyses are necessary for precise staging.

Sensitization of rat gastrointestinal tract to acetylcholine and histamine produced by X-radiation

Abdominal x-radiation produces both acute and chronic disturbances of gastrointestinal motility. Anaesthetized Albino-Oxford rats received one-session x-radiation (absorbed dose 10 Gy) of whole abdomen. Two hours after irradiation the rats were sacrificed and segments of their gastrointestinal tract (gastric fundus, jejunum, ileum and ascending colon, were mounted in isolated organ bath. Acetylcholine and 5-hydroxytryptamine produced tonic contractions of all gut segments, while histamine did so only with gastric fundus. While contractile effect of 5-hydroxytryptamine was not affected by x-radiation, the responses of all gut segments on acetylcholine were potentiated and shifted towards lower concentrations. After x-radiation histamine produced concentration-dependent tonic contraction of previously unresponsive jejunum and ascending colon. The results of our study suggest that x-radiation produces acute sensitization of rat gastrointestinal tract to acetylcholine and histamine.

The effects of excitatory amino acids on isolated gut segments of the rat

Glutamate and aspartate are excitatory neurotransmitters in both central and peripheral nervous systems, acting on ionotropic and metabotropic receptors. In our study we have examined the effects of glutamate, aspartate, N-methyl-d-aspartate (NMDA), kainic acid and (+/-)-1-aminocyclopentane-cis-1,3-dicarboxylic acid (ACPD) on tone and spontaneous activity of isolated rat gastric fundus, jejunum, ileum, ascending colon and rectum. Both glutamate and aspartate produced concentration-dependent tonic contractions of rat fundus and rectum; the other gut segments used in the study were not responsive. While only NMDA and kainic acid produced concentration-dependent tonic contractions of isolated rat gastric fundus, all three type-selective agonists of glutamate receptors (NMDA, kainic acid and ACPD) produced tonic contractions of isolated rat rectum. The results of our study suggest that glutamate and aspartate in rat gastric fundus activate excitatory intrinsic neurons through only ionotropic receptors (NMDA and non-NMDA receptors), while the same action in rat rectum is mediated through both ionotropic and metabotropic receptors.

[Long-term oral administration of etoposide in the treatment of patients with advanced non-small-cell carcinoma of the lung. The second phase of a clinical study]

Over the period from May 1989 to May 1992 thirty-four patients with advanced non-small cell lung cancer (NSCLC) were treated with prolonged administration of oral etoposide. Etoposide was administered in a dose of 50 mg/m2 a day for 21 days. Nine (26%) patients partially responded to the treatment that lasted 2-7 months (median 5 months). Median survival time was 6 months, and 1-year survival was 32%. The most common toxic events were alopecia and myelosuppression. No patient died of treatment-related toxicity. Results of this study demonstrate moderate efficiency of the prolonged administration of oral etoposide to patients with advanced NSCLC.

[Carboplatin-etoposide-bleomycine chemotherapy protocol in the treatment of patients with metastatic non-seminomatous germ-cell testicular tumours with good prognosis]

Fifteen patients with metastatic non-seminomatous germ-cell tumours with good prognosis were treated with carboplatin-etoposide-bleomycine chemotherapy. Patients were followed-up from 8 to 56 months (median 32 months). In 13 patients there was no evidence of the disease and in 2 patients recurred, but recovered after the subsequent secondary chemotherapy (cisplatin-bleomycine-vincristine). Signs and symptoms of toxicity included alopecia in 93% of patients, nausea and vomiting in 40%, while in respect of haematological toxicity, leucopenia was observed in all 15 patients, thrombocytopenia in 80%, and decrease of haemoglobinaemia in 60% of patients. Other toxicities were not observed. Carboplatin-etoposide-bleomycine chemotherapy is effective and little toxic, but a greater number of patients and a longer follow-up are needed for definitive evaluatin of this therapy in the treatment of patients with metastatic non-seminomatous germ-cell testicular tumours with good prognosis.

[Chemotherapy protocol "8 drugs in 1 day" in patients with recurrent malignant glioma]

22 patients with recurrent malignant gliome were treated with "8 drugs in 1 day" chemotherapy protocol. 3 patients achieved partial response, 7 achieved stable disease, while 12 had progressive disease. Median time to tumor progression for all patients was 13 weeks, while median survival time for all patients was 35 weeks. Hematological toxicities were the most common, resulting in treatment refusal in two patients. Other toxicities included gastrointestinal, nephrotoxicity and ototoxicity.

Incidence and growth of methylcholanthrene-induced tumors in mice with altered immunological status

BALB/c mice were treated s.c. with 3-methylcholanthrene (MCA), and tumor incidence and growth were followed for 9 months. Immunological status of mice was altered by various treatments. Thymectomized, lethally irradiated, bone marrow reconstituted mice served as T-cell deficient recipients. In order to suppress natural killer (NK)-cell/macrophage functions some mice were injected with silica particles; to enhance these functions some mice were given Corynebacterium parvum (CP). Silica and CP were given simultaneously with MCA to test their influence on the presumed function of surveillance of tumor incidence, and also 2 months after MCA to test their influence on the growth of greater numbers of transformed host cells. Almost all mice developed tumors at the inoculation site and at the end of the observation period there was no difference in tumor incidence among 9 experimental groups. However, in T-cell deficient mice we observed shorter tumor duration and earlier death than in normal mice. Silica particles appeared to enhance tumor growth but the differences compared to normal controls were not significant. A single injection of CP simultaneously with MCA caused earlier tumor appearance but also slowed its growth. In contrast, CP given 2 months after MCA significantly delayed the appearance of the tumors. In regard to the tumor growth immunosuppression had stronger effects in males than in females; the opposite was true for immunostimulation treatments. We concluded that immunological status does not influence long-term tumor incidence, but that both T-cell and NK-cell/macrophage compartments strongly influence the parameters of growth of chemically induced tumors, i.e., the immune and natural resistance mechanisms do not influence the frequency of de novo arising tumors but both can slow down tumor growth.