What is currently the best radiopharmaceutical for the hybrid PET/CT detection of recurrent medullary thyroid carcinoma?

Among thyroid malignancies, medullary thyroid carcinoma (MTC) has some very specific features. Production and secretion of large amounts of peptides occur in malignant transformed C cells with few exceptions, leading to high serum levels of calcitonin (Ctn) and carcinoembryonic antigen (CEA), that act after thyroidectomy as tumour markers warning for the presence of persistent or metastatic MTC. The availability of those serum biomarkers with an excellent sensitivity challenges medical imaging to localise the recurrent cancer tissue, since surgery is a major therapeutic option. The aims of this article are (i) to review literature evidence about the efficacy and tolerance of radiopharmaceuticals for 3 targets of PET/CT imaging (glucose metabolism, bioamines metabolism and somatostatin receptors) and also bone scintigraphy which is recommended in the Guidelines of European Society for Medical Oncology (ESMO; (ii) to compare the availability and the costs in relation with those radiopharmaceuticals, (iii) and to discuss a possible sequence of those examinations, in order to optimise spending and to minimise the overall radiation dose. In this context of recurrent MTC suspected on rising tumour markers levels after thyroidectomy, this survey of literature confirms that FDOPA is the best radiopharmaceutical for PET/CT with significant diagnostic performance if Ctn>150 pg/mL; an early image acquisition starting during the first 15 min is advised. In negative cases, FDG should be the next PET radiopharmaceutical, in particular if Ctn and CEA levels are rapidly rising, and PET with a somatostatin analogue labelled with gallium-68 when neither FDOPA nor FDG PET are conclusive. Bone scintigraphy could complement FDG-PET/CT if FDOPA is not available.

Bovine leukemia virus-induced clinical signs and morphological changes of encephalitozoonosis in rabbits.

Fourteen three-month-old rabbits spontaneously-infected with the microsporidium Encephalitozoon cuniculi Levaditi, Nicolau et Schoen, 1923 were inoculated intravenously with lymphocytes (Ly) from seropositive bovine leukemia virus infected cattle (Ly/BLV) or with fetal lamb kidney cells infected with bovine fetal leukemia (FLK/BLV). Thirteen rabbits were seropositive to BLV at least for a period of three months. Six rabbits died of pulmonary lesions. Chronic inflammatory lesions of encephalitozoonosis were found in six rabbits killed between 454 and 548 days of the observation period. Five animals bore subcutaneous granulomas. Immunohistochemically, E. cuniculi was demonstrated in the inflammatory lesions of rabbits studied. Control animals also spontaneously infected with E. cuniculi did not show clinical signs of encephalitozoonosis. Morphological changes were found incidentally in the form of small glial foci and focal interstitial nephritis in these animals. The combined action of BLV-E. cuniculi on the bodies of rabbits is proposed as a suitable model for the study of encephalitozoonosis in man with human immunodeficiency virus (HIV) infection.

DNA-mediated gene transfer into mammalian cells and cancer.

DNA-mediated introduction of genes into mammalian cells promises to be a powerful method for detecting sequences that control cell growth, confer resistance to toxic drugs, code for surface receptor proteins, or, indeed alter cell phenotype in any clearly defined way. The identification and molecular cloning of human transforming genes from neoplastic cells was enabled by the advances in existing techniques that allow DNA-gene transfer. Some methods of gene transfer which are inefficient today, should not be disregarded in the future. Every study of the genetic basis of cancer at the molecular level is an important step to the ability to influence human cancer cells and suppress their growth in vivo.

Expression of env gene of bovine leukemia virus in rodent cells.

The BamHI-BamHI fragment of the env gene of bovine leukemia virus (BLV) cloned in pMMEx expression vector was transfected into Chinese hamster cells. Monoclonal antibodies (MAbs) directed against both conformational and sequential epitopes of gp51 of BLV recognized viral polypeptides expressed in hamster cells in Western blotting and enzyme-linked immunosorbent assay.

The complex formation of influenza virus envelope glycoproteins with outer membrane proteins of Neisseria meningitidis or Borrelia burgdorferi.

The isolation of influenza virus envelope glycoproteins was achieved by one-step procedure consisting of treatment of purified virus with zwitterionic detergent and separation of viral constituents by sucrose density gradient centrifugation. Viral glycoproteins and proteins of outer membrane of N. meningitidis or B. burgdorferi formed complexes after removal of the detergent by dialysis. Complexing of viral glycoproteins and bacterial proteins was monitored by gel chromatography on Sepharose 6B, polyacrylamide gel electrophoresis and electron microscopy. It was demonstrated by immunoblot analysis, that virus-spirochete complexes elicited formation of antibodies in mice directed against osp A and osp B of spirochete, as well as against viral glycoproteins, respectively.

gp51 of bovine leukemia virus gene expression in hamster cells.

Recombinant pMMEx-bovine leukemia virus env gene DNA fragments were produced and expressed in eukaryotic cells. Clone C4, containing an SmaI-SmaI fragment of the gene coding for gp51, was co-transfected with pSV2neo DNA into Chinese hamster cells. About 800 geneticin-resistant cell clones were isolated and then morphologically and biologically characterized. The presence of gp51 encoding env gene fragments was detected in 17 of them by Southern blotting. The expression of gp51 gene in hamster cells was confirmed by Western blotting of their lysates with monoclonal antibodies (MAbs) directed against different epitopes of gp51 of bovine leukemia virus. The immunoreactivity of the expressed peptides with MAbs directed against neutralizing epitopes of gp51 of bovine leukemia virus was confirmed.

Expression of a bovine leukaemia virus envelope fusion protein in E. coli.

An expression plasmid containing 1.224 bp of the bovine leukaemia virus (BLV) env gene was constructed. The polypeptides encoded by six recombinant plasmids were analysed by electrophoretic transfer blot analysis. Two new proteins of 150-160 kDa and 60 kDa, respectively, were found in whole cellular extracts using sera of naturally infected cattle and/or by use of mouse monoclonal antibodies against gp51.

Bacterial expression of the p24 gag protein of the bovine leukaemia virus.

The possibility of expression of the gag gene of bovine leukaemia virus (BLV) in the bacterial system was investigated. The DNA fragment coding for the gag core 24 kDa protein of BLV was inserted into the pORF1 expression vector. The polypeptides expressed in E. coli were analysed by Western blotting. The bacterially synthesized antigens were detected by the serum of a BLV-infected cow and by mouse monoclonal antibodies against the native p24 gag protein.

Provirus integration of bovine leukemia virus into DNA of infected human myeloma cells.

Sixty clones of bovine leukemia virus-infected B-human myeloma ARH77 cells were isolated. The DNAs of all clones were examined for BLV provirus integration by Southern blotting analysis. Proviral sequences were found in DNAs of two clones. One of them (clone I B3) contained one proviral copy with a deletion of approximately 5.5 kb; the other one (clone I F9) carried three integrated proviruses. Viral proteins of 70,000, 42,000 and 35,000 M. W. were found in extracts of clone I F9. In clone I B3 only the 70,000 M.W. protein was detected.

Bovine leukemia provirus in the DNA of different infected host cells.

Bovine leukemia provirus is reported to be integrated in the DNA of different infected mammalian cells. We observed morphological transformation in BLV infected sheep fetal spleen, kidney, thymus and sternal cultures. The presence of BLV specific sequences in their genome was established after digestion with the restriction endonuclease EcoRI and hybridization with a BLV specific probe. Human myeloma ARH77 and myeloid K562 cells infected with BLV were virus productive as detected by a reverse transcriptase assay. The presence of proviral sequences was confirmed after Southern blotting analysis. Restriction digestion by SacI enzyme yielded a complete 8.9 kb BLV provirus in infected ARH77 cells and a smaller 7.5 kb BLV fragment in infected K562 cells.

Host range of murine sarcoma virus, its host modification and phenotypic mixing with endogenous virus.

The M(MSV)AG-50 cells produce competent ecotropic sarcoma virus which is able to transform several rodent embryo cells and replicate in them. The expanded host range has shown that the virus acquired some host information which facilitate the transformation of heterologous cells. The transformed cells were XC positive and with transformed phenotype in vitro. The genome of mouse sarcoma virus from nonproducer rat liver cells could be rescued by xenotropic endogenous virus. The obtained virus has shown the augmented host range for various embryo cells and for some mammalian cell lines as well. The virus with xenotropic coat efficiently transforms the cells, yielding cells with transformed phenotype. The majority of this virus were phenotypically mixed virions, with minority of probably recombinant virus as suggested by XC test. The modification of the virus during the passage through heterologous cells is discussed.