Effect of yeast and essential oil-enriched diets on critical determinants of health and immune function in Africanized Apis mellifera.

Nutrition is vital for health and immune function in honey bees (Apis mellifera). The effect of diets enriched with bee-associated yeasts and essential oils of Mexican oregano (Lippia graveolens) was tested on survival, food intake, accumulated fat body tissue, and gene expression of vitellogenin (Vg), prophenoloxidase (proPO) and glucose oxidase (GOx) in newly emerged worker bees. The enriched diets were provided to bees under the premise that supplementation with yeasts or essential oils can enhance health variables and the expression of genes related to immune function in worker bees. Based on a standard pollen substitute, used as a control diet, enriched diets were formulated, five with added bee-associated yeasts (Starmerella bombicola, Starmerella etchellsii, Starmerella bombicola 2, Zygosaccharomyces mellis, and the brewers' yeast Saccharomyces cerevisiae) and three with added essential oils from L. graveolens (carvacrol, thymol, and sesquiterpenes). Groups of bees were fed one of the diets for 9 or 12 days. Survival probability was similar in the yeast and essential oils treatments in relation to the control, but median survival was lower in the carvacrol and sesquiterpenes treatments. Food intake was higher in all the yeast treatments than in the control. Fat body percentage in individual bees was slightly lower in all treatments than in the control, with significant decreases in the thymol and carvacrol treatments. Expression of the genes Vg, proPO, and GOx was minimally affected by the yeast treatments but was adversely affected by the carvacrol and thymol treatments.

Corrigendum: Mifepristone as a Potential Therapy to Reduce Angiogenesis and P-Glycoprotein Associated With Glioblastoma Resistance to Temozolomide.

[This corrects the article DOI: 10.3389/fonc.2020.581814.].

Mifepristone as a Potential Therapy to Reduce Angiogenesis and P-Glycoprotein Associated With Glioblastoma Resistance to Temozolomide.

Glioblastoma, the most common primary central nervous system tumor, is characterized by extensive vascular neoformation and an area of necrosis generated by rapid proliferation. The standard treatment for this type of tumor is surgery followed by chemotherapy based on temozolomide and radiotherapy, resulting in poor patient survival. Glioblastoma is known for strong resistance to treatment, frequent recurrence and rapid progression. The aim of this study was to evaluate whether mifepristone, an antihormonal agent, can enhance the effect of temozolomide on C6 glioma cells orthotopically implanted in Wistar rats. The levels of the vascular endothelial growth factor (VEGF), and P-glycoprotein (P-gp) were examined, the former a promoter of angiogenesis that facilitates proliferation, and the latter an efflux pump transporter linked to drug resistance. After a 3-week treatment, the mifepristone/temozolomide regimen had decreased the level of VEGF and P-gp and significantly reduced tumor proliferation (detected by PET/CT images based on 18F-fluorothymidine uptake). Additionally, mifepristone proved to increase the intracerebral concentration of temozolomide. The lower level of O6-methylguanine-DNA-methyltransferase (MGMT) (related to DNA repair in tumors) previously reported for this combined treatment was herein confirmed. After the mifepristone/temozolomide treatment ended, however, the values of VEGF, P-gp, and MGMT increased and reached control levels by 14 weeks post-treatment. There was also tumor recurrence, as occurred when administering temozolomide alone. On the other hand, temozolomide led to 100% mortality within 26 days after beginning the drug treatment, while mifepristone/temozolomide enabled 70% survival 60-70 days and 30% survived over 100 days, suggesting that mifepristone could possibly act as a chemo-sensitizing agent for temozolomide.

Technetium-Radiolabeled Mannose-Functionalized Gold Nanoparticles as Nanoprobes for Sentinel Lymph Node Detection.

Gold nanoparticles (AuNPs) are considered valuable nanomaterials for the design of radiolabeled nanoprobes for single-photon emission computed tomography (SPECT) imaging. Radiolabeled and functionalized AuNPs could improve lymphatic mapping by enhancing the radioactive signaling of individual particles in the sentinel node. In this study, an alternative method for functionalizing commercial AuNps with mannose is described. The chemical derivatization and biofunctionalization of AuNPs were performed with lipoic acid and mannose, respectively. Several levels of mannose were tested; the thiolate hydrazinonicotinamide-glycine-glycine-cysteine (HYNIC) molecule was also used for 99mTc radiolabeling. Physicochemical characterization of this system includes U-V spectroscopy, dynamic light scattering, Fourier-transform infrared spectroscopy, and transmission electron microscopy. The most stable nanoprobe, in terms of the aggregation, radiolabeling efficiency, and purity, was tested in a sentinel lymph node model in a rat by microSPECT/computed tomography (CT) imaging. The SPECT images revealed that 99mTc-radiolabeled AuNPs functionalized with mannose can track and accumulate in lymph nodes in a similar way to the commercial 99mTc-Sulfur colloid, commonly used in clinical practice for sentinel lymph node detection. These promising results support the idea that 99mTc-AuNPs-mannose could be used as a SPECT contrast agent for lymphatic mapping.

Physicochemical and Tissue Response of PLA Nanofiber Scaffolds Sterilized by Different Techniques / Evaluación fisicoquímica y respuesta tisular de andamios nanofibrilares de PLA esterilizados por diferentes técnicas

ABSTRACT In recent years, tissue engineering has evolved considerably, due to the problems in the biomedical area concerning tissue regeneration therapies. Currently, work has been focused on the synthesis and physicochemical characterization of poly lactic acid scaffolds, a synthetic polyester that has been extensively study for its excellent biocompatibility and biodegradability. Moreover, sterilization strategies of scaffold are a crucial step for its application in tissue regeneration, however, the sterilization process have to maintain the structural and biochemical properties of the scaffold. Therefore, it is very important to carry out studies on the sterilization methods of the sample's material, since translational medicine is intended for in vivo applications. The aim of the present study was designed to analyze the effects of different sterilization techniques, i.e. ethylene oxide (ETO), gamma radiation (GR) and hydrogen peroxide- based plasma (H2O2) in biodegradable PLA scaffolds, and to determine the best sterilization technique to render a sterile product with minimal degradation and deformation, and good tissue response. Analysis of surface morphology showed that ETO and GR modified the PLA scaffolds without any change in its chemical composition. Moreover, the histological response showed that the scaffolds are biocompatible and those sterilized by GR showed a more severe inflammatory response, accompanied with the presence of giant foreign body cells. In conclusion, the results show that among sterilization techniques used in the preset study, the best results were observed with H2O2 sterilization, since it did not significantly modify the surface structure of the PLA fibers and their in vivo response did not cause an unfavorable tissue reaction.

RESUMEN En los últimos años, la ingeniería de tejidos ha evolucionado considerablemente, debido a las incógnitas en las terapias de regeneración en el área biomédica. Actualmente, se ha trabajado en la síntesis y caracterización fisicoquímica de andamios de poliácido láctico, el cual es un polímero sintético que se ha estudiado para aplicaciones en ingeniería de tejidos, debido a su biocompatibilidad y biodegradabilidad. El proceso de esterilización es un paso crucial en la aplicación de andamios en terapias de regeneración, sin embargo, la técnica de esterilización debe mantener las propiedades estructurales y bioquímicas del andamio. Por lo tanto, es muy importante realizar estudios sobre los métodos de esterilización de dichos andamios, ya que la medicina traslacional está diseñada para aplicaciones in vivo. El objetivo del presente estudio fue analizar los efectos de diferentes técnicas de esterilización como óxido de etileno (ETO), radiación gamma (GR) y plasma a base de peróxido de hidrógeno (H2O2) en andamios biodegradables de PLA, y determinar la mejor técnica de esterilización con mínima degradación y deformación, así como una respuesta tisular favorable. La estructura de la superficie de los andamios de PLA se modificó principalmente con las técnicas de óxido de etileno y radiación gamma, sin embargo, ninguna técnica modificó su composición química. Con la respuesta histológica se demostró que los andamios de PLA son biocompatibles y que los esterilizados por radiación gamma desencadenan una mayor respuesta inflamatoria y la formación de células gigantes de cuerpo extraño. En conclusión, los resultados muestran que las técnicas de esterilización utilizadas pueden modificar la morfología del andamio, sin embargo; los mejores resultados se observaron con la esterilización por plasma a base de peróxido de hidrógeno, ya que no modificó significativamente la estructura de la superficie de las fibras de PLA y su respuesta in vivo no provocó una reacción desfavorable en el tejido.

[99mTc-HYNIC-N-dodecylamide]: a new hydrophobic tracer for labelling reconstituted high-density lipoproteins (rHDL) for radioimaging.

Despite the widespread use of nanotechnology in radio-imaging applications, lipoprotein based delivery systems have received only limited attention so far. These studies involve the synthesis of a novel hydrophobic radio-imaging tracer consisting of a hydrazinonicotinic acid (HYNIC)-N-dodecylamide and 99mTc conjugate that can be encapsulated into rHDL nanoparticles (NPs). These rHDL NPs can selectively target the Scavenger Receptor type B1 (SR-B1) that is overexpressed on most cancer cells due to excess demand for cholesterol for membrane biogenesis and thus can target tumors in vivo. We provide details of the tracer synthesis, characterization of the rHDL/tracer complex, in vitro uptake, stability studies and in vivo application of this new radio-imaging approach.

Mifepristone Overcomes Tumor Resistance to Temozolomide Associated with DNA Damage Repair and Apoptosis in an Orthotopic Model of Glioblastoma.

The standard treatment for glioblastoma multiforme (GBM) is surgery followed by chemo/radiotherapy. A major limitation on patient improvement is the high resistance of tumors to drug treatment, likely responsible for their subsequent recurrence and rapid progression. Therefore, alternatives to the standard therapy are necessary. The aim of the present study was to evaluate whether mifepristone, an antihormonal agent, has a synergistic effect with temozolomide (used in standard therapy for gliomas). Whereas the mechanism of temozolomide involves damage to tumor DNA leading to apoptosis, tumor resistance is associated with DNA damage repair through the O6-methylguanine-DNA-methyltransferase (MGMT) enzyme. Temozolomide/mifepristone treatment, herein examined in Wistar rats after orthotopically implanting C6 glioma cells, markedly reduced proliferation. This was evidenced by a decreased level of the following parameters: a proliferation marker (Ki-67), a tumor growth marker (18F-fluorothymidine uptake, determined by PET/CT images), and the MGMT enzyme. Increased apoptosis was detected by the relative expression of related proteins, (e.g. Bcl-2 (B-cell lymphoma 2), Bax (bcl-2-like protein 4) and caspase-3). Thus, greater apoptosis of tumor cells caused by their diminished capacity to repair DNA probably contributed significantly to the enhanced activity of temozolomide. The results suggest that mifepristone could possibly act as a chemo-sensitizing agent for temozolomide during chemotherapy for GBM.

Liposomes Loaded with Cisplatin and Magnetic Nanoparticles: Physicochemical Characterization, Pharmacokinetics, and In-Vitro Efficacy.

With the aim improving drug delivery, liposomes have been employed as carriers for chemotherapeutics achieving promising results; their co-encapsulation with magnetic nanoparticles is evaluated in this work. The objective of this study was to examine the physicochemical characteristics, the pharmacokinetic behaviour, and the efficacy of pegylated liposomes loaded with cisplatin and magnetic nanoparticles (magnetite) (Cis-MLs). Cis-MLs were prepared by a modified reverse-phase evaporation method. To characterize their physicochemical properties, an evaluation was made of particle size, ζ-potential, phospholipid and cholesterol concentration, phase transition temperature (Tm), the encapsulation efficiency of cisplatin and magnetite, and drug release profiles. Additionally, pharmacokinetic studies were conducted on normal Wistar rats, while apoptosis and the cytotoxic effect were assessed with HeLa cells. We present a method for simultaneously encapsulating cisplatin at the core and also embedding magnetite nanoparticles on the membrane of liposomes with a mean vesicular size of 104.4 ± 11.5 nm and a ζ-potential of -40.5 ± 0.8 mV, affording a stable formulation with a safe pharmacokinetic profile. These liposomes elicited a significant effect on cell viability and triggered apoptosis in HeLa cells.

The Effect of Gabapentin and Tramadol in Cancer Pain Induced by Glioma Cell in Rat Femur.

Preclinical Research The presence of pain as part of the cancer process is variable. Glioblastoma multiform (GBM) can produce bone metastasis, a condition that involves other pathological phenotypes including neuropathic and inflammatory pain. Tramadol and gabapentin are drugs used in the treatment of neuropathic pain. However, there are no studies evaluating their analgesic effects in bone metastasis. We produced a pain model induced by the inoculation of glioma cells (105 ) into the rat femur, by perforating the intercodiloid fossa. Painful behavior was evaluated by measuring mechanical allodynia using the Von Frey test while thermal hyperalgesia was assessed in the plantar test. Histopathological features were evaluated and antinociceptive responses were compared using tramadol and gabapentin. The inoculation of cells inside the right femur produced nociceptive behaviors. Tramadol and gabapentin produced an anti-allodynic effect in this condition, but tramadol did not produce an anti-hyperalgesic response. The development of this model will allow us to perform tests to elucidate the pathology of bone metastasis, cancer pain, and in particular the pain produced by glioma. Drug Dev Res 78 : 173-183, 2017. © 2017 Wiley Periodicals, Inc.

Determination of Liposomal Cisplatin by High-Performance Liquid Chromatography and Its Application in Pharmacokinetic Studies.

Liposomes have been employed as carriers for antineoplastic drugs to improve delivery. We describe an HPLC-UV method for determining cisplatin levels in liposomal and biological samples, which represents an attractive alternative to the widely used flame atomic absorption spectroscopy. Liposomal cisplatin was extracted from liposomes, plasma and tissue samples by using acetonitrile and separated on a Symmetry C18 column. The mobile phase was a mixture of water, methanol and acetonitrile, and detection was performed at 254 nm. The method was linear in the range of 0.5-10 µg/mL. Using this method, cisplatin concentration was measured in plasma, kidney, liver and tumor at different times post-administration of liposomal cisplatin. This method is proved suitable for measuring the levels of cisplatin encapsulated in a liposomal system, in plasma or tissue samples of experimental animals, after intravenous administration of liposomal cisplatin. Owing to the small plasma volume employed, a complete pharmacokinetic study can be done with a single animal.

Antihormonal agents as a strategy to improve the effect of chemo-radiation in cervical cancer: in vitro and in vivo study.

BACKGROUND: Over the past few years, the concurrent use of cisplatin-based chemotherapy and radiation therapy has dramatically improved the local response and increased overall survival in early-stage cervical cancer. However, for the advanced stages of the disease this standard treatment has proved insufficient. We investigated the capacity of Mifepristone and ICI 182,780, which are anti-progestin and anti-estrogen drugs, respectively, to act as chemo-radiosensitizing agents in cervical cancer cells and cervix xenografts. METHODS: The effect of chemo-radiation alone or combined with Mifepristone or ICI 182,780 was evaluated in HeLa cells and with tumor growth in cervix xenografts. After concomitant chemo-radiotherapy, the effect of each of these antihormonal agents on apoptosis (determined by Annexing V assay) and the cell cycle phases were determined by flow cytometry. The expression of angiogenic factor VEGF in tumor samples was determined using quantitative RT-PCR analysis of VEGF gene expression. RESULTS: Compared to radiation alone or radiation/cisplatin therapy, there was significantly higher cytotoxicity and a greater antitumoral effect with the combined application of radiation/cisplatin and Mifepristone or ICI 182,780. Analyses of the apoptosis and cell cycle demonstrated changes only with ICI, not with Mifepristone, when was applied in combination with radiation/cisplatin. The analysis of VEGF mRNA expression levels in tumors at the end of the study demonstrated a significant inhibition, compared to radiation only or the radiation/cisplatin treatment, after concurrent chemo-radiotherapy and each one of the antihormonal drugs. CONCLUSION: Mifepristone and ICI 182,780 may be potentially promising chemo-radiosensitizing compounds to be used in combination with ionizing irradiation and cisplatin in the treatment of patients with advanced cervical cancer.

[Enteropathogens responsible for gastrointestinal disorders in HIV patients]. / Agentes patógenos responsables de trastornos gastrointestinales en sujetos infectados con VIH.

Gastrointestinal disorders or GID are debilitating conditions common in individuals infected by the human immunodeficiency virus (HIV), capable of leading to death. Numerous etiological agents and pathophysiological mechanisms have been involved in this status. Although the use of highly active antiretroviral therapy (HAART) in many countries has greatly reduced the prevalence of gastrointestinal infections, enteric pathogens such as bacteria, parasites, fungi and viruses may still act as opportunist agents in these patients. Cytomegalovirus, adenovirus, calicivirus, astrovirus, rotavirus, enterovirus, picobirnavirus and some more recently described, like bocavirus and Aichi virus, have been detected in HIV patients. However, except for cytomegalovirus, which is an established etiological agent of GID in these patients, the role of the other viruses remains unclear. Several species of Cryptosporidium, microsporidia, Salmonella, atipical mycobacteria and Campylobacter jejuni, have also been recognized as important causes of GID in HIV patients. The progressive incorporation of increasingly sensitive immunological and molecular assays for antigen, antibody and pathogens detection from faeces, has improved the diagnosis of diarrhea and contributed to clarify the etiological significance of some microorganisms in immunocompetent patients. In Venezuela, some information is available about the prevalence of enteric pathogens in immunocompromised patients infected with HIV. The identification of the etiologic agent responsible for this condition may be useful for the management and treatment of these patients, for whom viral enteritis is a disease, which reduces their quality of life and causes a high public health spending.

Agentes patógenos responsables de trastornos gastrointestinales en sujetos infectados con VIH / Enteropathogens responsible of gastrointestinal disorders in HIV patients

Los trastornos gastrointestinales o TGI son afecciones debilitantes muy comunes en individuos infectados con el virus de inmunodeficiencia humana (VIH), que pueden conducir a muerte. Numerosos agentes etiológicos y mecanismos patofisiológicos han sido propuestos causar esta afección. A pesar del uso de terapia antirretroviral, que ha reducido enormemente la prevalencia de TGI en estos pacientes, patógenos entéricos como virus, bacterias, parásitos y hongos logran actuar todavía como agentes oportunistas. Citomegalovirus, adenovirus, calicivirus, astrovirus, rotavirus, enterovirus, picobirnavirus y algunos más recientemente descritos, como bocavirus y Aichi virus han sido detectados en pacientes con VIH. Sin embargo, a excepción del citomegalovirus, hay muy poca certeza acerca del papel que juegan algunos de ellos en estas afecciones. Varias especies de Criptosporidium, microsporidos, Salmonella, micobacterias atípicas y Campylobacter jejuni han sido reconocidos también como una importante causa de TGI en estos pacientes. La progresiva incorporación de técnicas inmunoenzimáticas y moleculares, cada vez más sensibles para la detección de antígenos, anticuerpos y agentes patógenos en heces ha mejorado el diagnóstico de las diarreas y contribuido a esclarecer la importancia etiológica de algunos microorganismos en los pacientes inmunocompetentes. En Venezuela existen algunos datos acerca de la prevalencia de patógenos entéricos en pacientes inmunodeficientes infectados con VIH. La identificación del agente etiológico responsable de TGI podría ser de gran utilidad para el manejo y tratamiento de estos pacientes, para quienes la enteritis viral es una manifestación morbosa que reduce la calidad de vida y ocasiona un elevado gasto en salud pública.

Gastrointestinal disorders or GID are debilitating conditions common in individuals infected by the human immunodeficiency virus (HIV), capable of leading to death. Numerous etiological agents and pathophysiological mechanisms have been involved in this status. Although the use of highly active antiretroviral therapy (HAART) in many countries has greatly reduced the prevalence of gastrointestinal infections, enteric pathogens such as bacteria, parasites, fungi and viruses may still act as opportunist agents in these patients. Cytomegalovirus, adenovirus, calicivirus, astrovirus, rotavirus, enterovirus, picobirnavirus and some more recently described, like bocavirus and Aichi virus, have been detected in HIV patients. However, except for cytomegalovirus, which is an established etiological agent of GID in these patients, the role of the other viruses remains unclear. Several species of Cryptosporidium, microsporidia, Salmonella, atipical mycobacteria and Campylobacter jejuni, have also been recognized as important causes of GID in HIV patients. The progressive incorporation of increasingly sensitive immunological and molecular assays for antigen, antibody and pathogens detection from faeces, has improved the diagnosis of diarrhea and contributed to clarify the etiological significance of some microorganisms in immunocompetent patients. In Venezuela, some information is available about the prevalence of enteric pathogens in immunocompromised patients infected with HIV. The identification of the etiologic agent responsible for this condition may be useful for the management and treatment of these patients, for whom viral enteritis is a disease, which reduces their quality of life and causes a high public health spending.

Multimeric system of 99mTc-labeled gold nanoparticles conjugated to c[RGDfK(C)] for molecular imaging of tumor α(v)ß(3) expression.

Integrin α(V)ß(3) plays a critical role in tumor angiogenesis and metastasis. Suitably radiolabeled cyclic RGD peptides can be used for noninvasive imaging of α(V)ß(3) expression. The aim of this research was to prepare a multimeric system of technetium-99m-labeled gold nanoparticles conjugated to c[RGDfK(C)] and to evaluate its biological behavior as a potential radiopharmaceutical for molecular imaging of tumor angiogenesis. Hydrazinonicotinamide-GGC (HYNIC-GGC) and c[RGDfK(C)] peptides were synthesized and conjugated to gold nanoparticles (AuNP, 20 nm) by means of spontaneous reaction of the thiol groups of cysteine. The nanoconjugate was characterized by TEM, FT-IR, UV-vis, XPS, and Raman spectroscopy. To obtain (99m)Tc-HYNIC-GGC-AuNP-c[RGDfK(C)] ((99m)Tc-AuNP-RGD), the (99m)Tc-HYNIC-GGC radiopeptide was first prepared and added to 1.5 mL of AuNP solution (1 nM) followed by c[RGDfK(C)] (10 µL, 50 µM) at 18 °C with stirring for 15 min. Radiochemical purity (RP) was determined by size-exclusion HPLC and ITLC-SG analyses. In vitro binding studies were carried out in α(V)ß(3) receptor-positive C6 glioma cancer cells. Biodistribution studies were accomplished in athymic mice with C6-induced tumors with blocked and nonblocked receptors, and images were obtained using a micro-SPECT/CT. TEM and spectroscopy techniques demonstrated that AuNPs were functionalized with peptides. RP was 96 ± 2% without postlabeling purification. (99m)Tc-AuNP-RGD showed specific recognition for α(V)ß(3) integrins expressed in C6 cells, and 3 h after i.p. administration in mice, the tumor uptake was 8.18 ± 0.57% ID/g. Micro-SPECT/CT images showed evident tumor uptake. (99m)Tc-AuNP-RGD demonstrates properties suitable for use as a target-specific agent for molecular imaging of tumor α(V)ß(3) expression.

(99m)Tc-labelled gold nanoparticles capped with HYNIC-peptide/mannose for sentinel lymph node detection.

UNLABELLED: The aim of this research was to prepare a multifunctional system of technetium-99m-labelled gold nanoparticles conjugated to HYNIC-GGC/mannose and to evaluate its biological behaviour as a potential radiopharmaceutical for sentinel lymph node detection (SLND). METHODS: Hydrazinonicotinamide-Gly-Gly-Cys-NH(2) (HYNIC-GGC) peptide and a thiol-triazole-mannose derivative were synthesized, characterized and conjugated to gold nanoparticles (AuNP, 20 nm) to prepare a multifunctional system of HYNIC-GGC-AuNP-mannose by means of spontaneous reaction of the thiol (Cys) present in HYNIC-GGC sequence and in the thiol-mannose derivative. The nanoconjugate was characterized by transmission electron microscopy (TEM), IR, UV-Vis, Raman, fluorescence and X-ray photoelectron spectroscopy (XPS). Technetium-99m labelling was carried out using EDDA/tricine as coligands and SnCl(2) as reducing agent with further size-exclusion chromatography purification. Radiochemical purity was determined by size-exclusion HPLC and ITLC-SG analyses. In vitro binding studies were carried out in rat liver homogenized tissue (mannose-receptor positive tissue). Biodistribution studies were accomplished in Wistar rats and images obtained using a micro-SPECT/CT system. RESULTS: TEM and spectroscopy techniques demonstrated that AuNPs were functionalized with HYNIC-GGC-NH(2) and thiol-mannose through interactions with thiol groups and the N-terminal amine of cysteine. Radio-chromatograms showed radiochemical purity higher than 95%. (99m)Tc-EDDA/HYNIC-GGC-AuNP-mannose ((99m)Tc-AuNP-mannose) showed specific recognition for mannose receptors in rat liver tissue. After subcutaneous administration of (99m)Tc-AuNP-mannose in rats (footpad), radioactivity levels in the popliteal and inguinal lymph nodes revealed that 99% of the activity was extracted by the first lymph node (popliteal extraction). Biodistribution studies and in vivo micro-SPECT/CT images in Wistar rats showed an evident lymph node uptake (11.58 ± 1.98 %ID at 1 h) which was retained during 24 h with minimal kidney accumulation (0.98 ± 0.10 %ID) and negligible uptake in all other tissues. CONCLUSIONS: This study demonstrated that (99m)Tc-AuNP-mannose remains within the first lymph node during 24 h and therefore might be useful as a target-specific radionanoconjugate for SLND using "1-day" or "2-day" conventional protocols.

Lys3-bombesin conjugated to 99mTc-labelled gold nanoparticles for in vivo gastrin releasing peptide-receptor imaging.

UNLABELLED: The gastrin releasing peptide-receptor (GRP-r) is over-expressed in breast and prostate cancer and lymph node metastases. Lys3-bombesin is a peptide that binds with high affinity to GRP-r. The aim of this research was to prepare a multifunctional system of technetium-99m labelled gold nanoparticles conjugated to Lys3-bombesin/HYNIC-GGC and to evaluate its biological behaviour as a potential radiopharmaceutical for in vivo GRP-r imaging. METHODS: Lys3-bombesin and hydrazinonicotinamide-Gly-Gly-Cys-NH2 (HYNIC-GGC) peptides were conjugated to gold nanoparticles (AuNP, 20 nm) to prepare a multifunctional system of HYNIC-GGC-AuNP-Lys3-bombesin by means of spontaneous reaction of the thiol (Cys) present in HYNIC-GGC sequence and the amine of Lys3-bombesin. The nanoconjugate was characterized by transmission electron microscopy (TEM), IR, UV-Vis, Raman, and X-ray photoelectron spectroscopy (XPS). Technetium-99m labelling through the HYNIC-GGC ligand was carried out using EDDA/tricine as coligands and SnCl2 as reducing agent with further size exclusion chromatography purification. Radiochemical purity was determined by size exclusion HPLC and ITLC-SG analyses. In vitro binding studies were carried out in human prostate cancer PC-3 cells (GRP-r positive cells). Biodistribution studies were accomplished in athymic mice with PC-3 induced tumours and images obtained using a micro-SPECT/CT system. RESULTS: TEM and spectroscopy techniques demonstrated that AuNPs were functionalized with HYNIC-GGC-NH2 and Lys3-bombesin through interactions with thiol groups of Cysteine and the N-terminal and epsilon-amine of Lysine respectively. Radio-chromatograms showed radiochemical purity higher than 95%. 99mTc-EDDA/HYNIC-GGC-AuNP-Lys3-bombesin (99mTc-AuNP-Lys3-bombesin) showed specific recognition for GRP-r over-expressed in PC-3 cells. After administration of 99mTc-AuNP-Lys3-bombesin in mice the pancreas-to-blood ratio was 36 at 1 h demonstrating ability to target in vivo GRP receptor-bearing cells. In vivo micro-SPECT/CT images in mice showed an evident tumour uptake (6.39 +/- 0.83% IA/g at 1 h). CONCLUSIONS: This study demonstrated that the 99mTc-AuNP-Lys3-bombesin multifunctional system shows specific recognition for GRP-r and suitable properties to be used as a molecular imaging agent.

Spatial dose distributions in solid tumors from 186Re transported by liposomes using HS radiochromic media.

PURPOSE: A procedure for the measurement of spatial dose rate distribution of beta particles emitted by 186Re-liposomes in tumoral tissue, using HS GafChromic films, is presented. METHODS: HNSCC xenografts were intratumorally injected with 3.7 or 11.1 MBq of 186Re-liposomes, and planar gamma camera images were acquired to determine the liposome retention in the tumor. After imaging, rats were sacrificed and tumors were excised and processed in slices; HS film sections were placed between slices and the tumor lobe was reassembled. Tumors and films were kept in the dark at 4 degrees C for 18 h. After irradiation, films were removed and response was read using a transmission scanner. Films were analyzed to determine two-dimensional spatial dose rate distributions and cumulative dose volume histograms. Dose rate distributions were quantified using a 60Co calibration curve, the 186Re physical half-life, and a perturbation factor that takes into account the effect of the film protective layer. RESULTS: Dose rate distributions are highly heterogeneous with maximal dose rates about 0.4 Gy h(-1) in tumors injected with 3.7 MBq and 1.3 Gy h(-1) in tumors injected with 11.1 MBq. Dose volume histograms showed dose distributed in more than 95% and 80% of the tumor when injected with the lower and the higher activity, respectively. CONCLUSION: The described procedures and techniques have shown the potential and utility of HS GafChromic film for determination of dose rate distributions in solid tumors injected intratumorally with 186Re-liposomes. The film's structure and the liposomes' biodistribution must be taken into account to obtain quantitative dose measurements.

Mediastinal node and diaphragmatic targeting after intracavitary injection of avidin/99mTc-blue-biotin-liposome system.

A method for delivering drugs to sites of disease extension in mediastinal nodes is described. Mediastinal node and lymphatic distributions were determined after intracavitary injection of the avidin/biotin-liposome system in normal rats. The effect of the injected dose on lymphatic targeting of liposomes after intraperitoneal injection of (99m)Tc-blue-biotin-liposomes and intrapleural injection of avidin, and vice versa, is presented. Scintigraphic imaging was used to follow the movement of (99m)Tc-blue-biotin-liposomes to determine the pharmacokinetics and organ uptake. Tissue biodistribution studies were performed 22 h after injection of the (99m)Tc-blue-biotin-liposomes. Results indicated that independent of the cavity in which each agent was injected, a dose of 5.0 mg of each agent results in higher mediastinal node targeting (8%-10% ID/Organ) as compared with the injection of a 0.5 mg dose (2%-5% ID/Organ, p < 0.05). Targeting of diaphragm and associated lymphatics was observed when (99m)Tc-blue-biotin-liposomes were injected in peritoneum and avidin in pleural space. In contrast, pleural, and pericardial lymphatic targeting was observed when (99m)Tc-blue-biotin-liposomes were injected in pleural space and avidin in peritoneum. Intracavitary injection of the avidin/biotin-liposome system could potentially be used for the delivery of prophylactic drugs that could reduce tumor metastasis and infection spread to mediastinal nodes.

Avidin/biotin-liposome system injected in the pleural space for drug delivery to mediastinal lymph nodes.

The objective of this study was to develop a more effective liposome-based method for delivering drugs to mediastinal nodes. Nodal uptake was determined after intrapleural injection of the avidin/biotin-liposome system in normal rats. The effect of injection sequence (avidin injected 2 h before biotin-liposomes and vice versa), volume injected, and administered dose of the agents is described. Pharmacokinetics of the avidin/biotin-liposome system was monitored with scintigraphic imaging by labeling the biotin-liposomes with technetium-99m ((99m)Tc). To identify the nodes during the biodistribution studies, patent blue dye was encapsulated in the biotin-liposomes. Tissue biodistribution studies were performed 22 h after injection of the (99m)Tc-blue-biotin-liposomes. When avidin was injected before (99m)Tc-blue-biotin-liposomes, better mediastinal node targeting (15.7%; p < 0.05) was achieved than when biotin-liposomes were injected first (8.3%) or when only biotin-liposomes were injected (1.0%). Injection of a small dose of liposomes (0.5 mg phospholipid) and avidin (0.5 mg) resulted in the most favorable drug delivery to mediastinal nodes and other organs. Intrapleural injection of the avidin/biotin-liposome system could potentially be used for drug delivery to disease processes such as lung cancer, anthrax, and tuberculosis that invade mediastinal nodes and use them as centers of incubation and dissemination.

A novel approach for the increased delivery of pharmaceutical agents to peritoneum and associated lymph nodes.

A novel method for prolonging the retention of liposomes in the peritoneum while increasing liposome deposition in lymph nodes that drain the peritoneum is described. An aliquot (1 ml) of technetium-99m ((99m)Tc)-biotin-liposomes encapsulating blue dye was injected intraperitoneally in rats. Thirty minutes after administration of the (99m)Tc-blue-biotin-liposomes, five rats (experimental) were administered avidin (5 mg) intraperitoneally, whereas the remaining five rats served as controls. Scintigraphic images were acquired at baseline and 1 and 24 h after the liposome injection followed by a tissue biodistribution study. Images at 24 h clearly demonstrated very different distributions between the experimental and control animals. In experimental rats, most of the activity was visualized in the abdominal region, and in abdominal and mediastinal lymph nodes. The percentage of the injected dose (% ID) in the blood was significantly higher in the control group than in the experimental group (14.0 +/- 1.7 versus 0.17 +/- 0.03%; P < 0.001). The % ID in the spleen was also significantly greater for controls (23.3 +/- 3.9%) compared with the experimental group (0.78 +/- 0.8%; P = 0.001). Significant (99m)Tc activity was detected in blue-stained abdominal nodes (4.7%) and mediastinal nodes (2.3%) from the experimental animals, whereas no blue-stained nodes were detectable in the control animals. The intraperitoneal biotin-liposome/avidin delivery system described in this study could potentially be used for delivery of liposome-encapsulated drugs to disease processes that become disseminated in the peritoneum such as metastatic ovarian, gastric, and colorectal cancer, as well as infectious peritonitis.