ICP27 protein of Marek's disease virus interacts with SR proteins and inhibits the splicing of cellular telomerase chTERT and viral vIL8 transcripts

All herpesviruses have a post-transcriptional regulatory protein that prevents precursor mRNA splicing and leads to the shutting off of host protein synthesis. The ICP27 protein of herpes simplex virus 1 (HSV-1) is the prototype of these proteins. Marek's disease virus (MDV-1), an alphaherpesvirus that induces lymphoma in birds, also has an ICP27 protein that is produced in lytic MDV-1-infected cells. We characterized this protein. We demonstrated ICP27 production in latently infected MSB-1 cells, but only on MDV-1 reactivation. ICP27 was found predominantly in specific structures within the nucleus. The ICP27 of MDV-1 colocalized and interacted with SR proteins. We demonstrated inhibitory effects of MDV-1 ICP27 on the splicing of both the viral vIL8 and cellular chTERT (telomerase reverse transcriptase) genes. Thus, the ICP27 of MDV-1 plays a similar role to the ICP27 of HSV-1 and may be involved in MDV-1 replication and the development of Marek's disease.

Combination of gemcitabine and cetuximab in patients with advanced cholangiocarcinoma: A phase II study of the Belgian Group of Digestive Oncology

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Background: Cholangiocarcinomas (CCK) are uncommon tumors with an increasing incidence and a poor prognosis. Epidermal growth factor receptor (EGFR) expression and activation in CCK have been demonstrated.

Methods: We conducted a multicenter phase II trial combining cetuximab (Ctx), an anti-EGFR chimerized IgG1 monoclonal antibody, to gemcitabine (Gem). Patients with either locally advanced (LA) or metastatic (M) CCK (excluding gallbladder) were included; no prior systemic therapy was allowed. Ctx was administrated at the initial dose of 400 mg/m2 and further injections at 250 mg/m2 every 7 days, and Gem was administrated at 1000 mg/m2 on days 1, 8, and 15 every 4 weeks. The primary endpoint was the progression-free survival (PFS) rate at 6 months. A Simon 2-stage design was used. We hypothesized that Gem/Ctx would improve 6 month-PFS rate from 20% to 40%. We needed 3 patients with PFS ≥ 6 months from the first 13 to further include a total of 43 patients.

Results: Forty-four patients with advanced CCK (41% LA/59%M) were enrolled from 09/2008 to 01/2010. Median age was 61.5 years (range 40-86) and baseline ECOG PS was 0 for 68% and 1 for 32% of the patients. Forty-three percent of the patients had prior surgery. Forty-six percent of the patients were free from progression at 6 months. Median PFS was 5.8 months (95% CI, 4.4-7.4 m) and median overall survival was 11.6 months (95% CI, 8.7-14.6 m). Nine patients (20.9%) had partial response with a median duration of 5 months (range 2-10 m). Disease control rate (PR + SD > 8 weeks) was 81.4%. The most common grades 3/4 related-toxicities were haematological abnormalities (47.7%), skin rash (13.6%) and fatigue (11.3%). Due to toxicity, 6 patients discontinued study treatment; 14 and 3 patients had a Gem and Ctx dose reduction respectively. Among the nine responders, 8 experienced a skin rash of at least grade 2, suggesting a relationship between skin toxicity and efficacy.

Conclusions: Our study met its endpoint, i.e., a PFS rate of 46% at 6 months, suggesting that Gem-Ctx combination had promising activity with a manageable toxicity profile in advanced CCK. Adding Ctx to the new standard of care Gem-cisplatin deserves further investigations in CCK.

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Synthesis and physicochemical characterization of Gd-C4-thyroxin-DTPA, a potential MRI contrast agent. Evaluation of its affinity for human serum albumin by proton relaxometry, NMR diffusometry, and electrospray mass spectrometry

Gd-C(4)-thyroxin-DTPA, a potential MRI contrast agent, was synthesized from Gd-DTPA and thyroxine, which interacts strongly with human serum albumin (HSA). It was characterized in water by its relaxometric properties and its stability versus zinc transmetalation. The affinity of the complex for HSA was studied by using three different methods: proton relaxometry, NMR diffusometry, and electrospray mass spectrometry. From the results, it appears that Gd-C(4)-thyroxin-DTPA exhibits a relatively high relaxivity (r(1) = 9.01 s(-1) mM(-1) at 1.5 T and 310 K), a good stability versus zinc transmetalation, and a strong interaction with HSA (K(a) approximately 10,000 M(-1) with two binding sites). The kinetics of the exchange between the bound and the free form of the complex was evaluated by the NMR diffusometry technique. Competition experiments have allowed the assignment of the chelate's binding site on HSA.

How to perform accurate and reliable measurements of longitudinal and transverse relaxation times of MRI contrast media in aqueous solutions

Knowledge of the longitudinal and transverse relaxation times (T(1) and T(2)) of water protons in an aqueous solution of an MRI contrast agent is essential for its characterization. These parameters can be measured at low field on low resolution spectrometers or at high field on high resolution spectrometers. The reliability and the accuracy of T(1) and T(2) measurements rely on several experimental settings and on the equation used to fit the data. Examples of the importance of careful adjustment of the most important parameters are illustrated through several measurements performed on a low-resolution, low-magnetic field instrument. In addition, some specificities of T(1) and T(2) measurements on high-resolution, high-magnetic field spectrometers are pointed out.

Iron oxide based MR contrast agents: from chemistry to cell labeling

Superparamagnetic iron oxide nanoparticles can be used for numerous applications such as MRI contrast enhancement, hyperthermia, detoxification of biological fluids, drug delivery, or cell separation. In this work, we will summarize the chemical routes for synthesis of iron oxide nanoparticles, the fluid stabilization, and the surface modification of superparamagnetic iron oxide nanoparticles. Some examples of the numerous applications of these particles in the biomedical field mainly as MRI negative contrast agents for tissue-specific imaging, cellular labeling, and molecular imaging will be given. Larger particles or particles displaying a non-neutral surface (thanks to their coating or to a cell transfection agent with which they are mixed) are very useful tools, although the cells to be labeled have no professional phagocytic function. Labeled cells can then be transplanted and monitored by MRI in a broad spectrum of applications. Direct in vivo magnetic labeling of cells is mainly performed by intravenous injection of long-circulating iron oxide-based MRI contrast agents, which can extravasate and/or undergo a cellular uptake in an amount sufficient to allow an MRI visualization of areas of interest such as inflamed regions or tumors. Particles with long circulation times, or able to induce a strong negative effect individually have been also modified by conjugation to a ligand, so that their cellular uptake, or at least their binding to the cell surface, could occur through a specific ligand-receptor interaction, in vivo as well as in vitro. Thus, experimentally as well as in a few trials on humans, iron oxide particles currently find promising applications.

Chronic traumatic brain injury in a dog

Chronic traumatic brain injury is rare in man and has not been previously documented in dogs. This report describes a 2-year-old female American Staffordshire bull terrier that was referred with forelimb and hindlimb ataxia, decreased vigilance and disorientation following repeated aggression and physical abuse by its owner. A diffuse cortical lesion was suspected. Cerebrospinal fluid analysis revealed neutrophilic pleocytosis and computed tomography showed marked widening of the cerebral sulci with mild bilateral ventriculomegaly. The dog was humanely destroyed in view of the poor prognosis. Necropsy examination revealed narrowing of the cerebral cortical gyri and consequent widening of the sulci without distortion or displacement of the neural parenchyma. These features were consistent with bilateral diffuse cortical atrophy. Microscopically, there were chronic subarachnoid haemorrhages and the cortical subpial layer displayed spongiosis, capillary hyperplasia, astrocytosis, microgliosis and frequent neuronal necrosis occurring in a characteristic laminar pattern. This histopathological pattern of damage was significantly different from that previously described in people suffering from repeated traumatic brain injuries over a long period of time.

Acute and chronic gastric volvulus: radical different prognosis and management. Case report

Gastric volvulus is an uncommon entity. Management is principally surgical. Diagnosis is often delayed because of the non-specific nature of the symptoms. The authors report two cases of gastric volvulus seen in a six month period. The first is an acute presentation diagnosed by computed tomography with incarceration and necrosis of the stomach, the transverse colon and great omentum. The issue was immediate laparotomy for total gastrectomy, colectomy, terminal colostomy and omentectomy. The patient survived, and the colostomy was closed and continuity restored three months later. The second one is a chronic form diagnosed by gastroscopy and barium swallow radiography. The treatment was elective with closure of the hiatus, Nissen procedure and gastropexy. The pathophysiology, classification and treatment of those two kinds of volvulus are briefly reviewed.

Lanthanide complexes for magnetic resonance and optical molecular imaging

Lanthanide complexes are more and more used in biomedical imaging as contrast agents (CA). The development of these paramagnetic complexes as CA for medical magnetic resonance imaging (MRI) and luminescent probes for optical imaging is very complementary. Gd complexes are well known as CA for MRI and Eu/Tb complexes are often used in microscopy or fluorescence imaging. Each imaging technique has its limitation: low sensitivity but high spatial resolution for MRI and limited penetration but high sensitivity for optical imaging. A bimodal agent can be used for these two methods and give more informations, they can be visualized simultaneously by light and MR imaging. Such compounds are based on the coordination chemistry of the lanthanide ions with an organic ligand to form a stable complex and on the properties of the lanthanide ions. Gd complexes with a chromophore allows also the luminescent detection. This review describes the properties of the lanthanide ions and of their complexes and gives some typical applications of the complexes. The luminescence properties show high quantum yield and long luminescence lifetimes. The relaxometric data of the Gd complexes are comparable or higher than commercial and clinically Gd-DTPA derivatives.

Genetic diversity, population structure and sex-biased dispersal in three co-evolving species

Genetic diversity and spatial structure of populations are important for antagonistic coevolution. We investigated genetic variation and population structure of three closely related European ant species: the social parasite Harpagoxenus sublaevis and its two host species Leptothorax acervorum and Leptothorax muscorum. We sampled populations in 12 countries and analysed eight microsatellite loci and an mtDNA sequence. We found high levels of genetic variation in all three species, only slightly less variation in the host L. muscorum. Using a newly introduced measure of differentiation (Jost's D(est)), we detected strong population structuring in all species and less male-biased dispersal than previously thought. We found no phylogeographic patterns that could give information on post-glacial colonization routes - northern populations are as variable as more southern populations. We conclude that conditions for Thompson's geographic mosaic of coevolution are ideal in this system: all three species show ample genetic variation and strong population structure.

Targeting ctla-4 directly on melanoma cells: A possible novel perspective in the immunotherapy of cutaneous melanoma

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Background: CTLA-4 (CD152) is an omodimeric membrane glycoprotein which behaves as the major negative regulator of T cell-mediated immune response. CTLA-4 inhibitory function in T cells mainly occurs upon engagement with the B7 ligands expressed on antigen presenting cells, resulting in inhibition of cytokine production and T cell proliferation. CTLA-4 expression has also been documented in established human melanoma cell lines and primary melanoma tumours. The aim of this study was to investigate the expression and functional role of CTLA-4 in primary melanoma cultures derived from biopsies of metastatic melanoma patients. Methods: Seven primary cultures were derived from melanoma samples by mechanical tissue dissociation, enzymatic digestion and filtration of single cell suspensions. Flow cytometry (FACS) with an anti-melanoma (MCSP) mAb was used to assess the growth of melanoma cells. CTLA-4 expression analysis was performed by FACS and real-time PCR. Cytokine secretion and apoptotic cells were evaluated by Elisa and Annexin V/PI staining after treatment with an agonistic anti-CTLA-4 mAb (3D5). The angiogenic property of melanoma culture supernatants was evaluated on mesenchimal stromal cells (msc) isolated from human thoracic aortas. All the study was approved by our Institutional Ethics Committee and patients gave written informed consent. Results: Constitutive CTLA-4 expression was found on all melanoma cultures with variable intensity at both the protein and transcript levels. CTLA-4 expressed by these cells is functional as its ligation, with an anti-CTLA-4 agonistic mAb, is able to induce inhibition of cell proliferation, due to apoptosis induction, and of IL-8, TNF-alpha and VEGF cytokine secretion. Moreover, CTLA-4 ligation down-modulates the ability of melanoma culture supernatants to induce angiogenic differentiation of msc as detected by the acquisition of their endothelial phenotype. Conclusions: Given the physiologic inhibitory function of CTLA-4, our results suggest its possible role in the functional biology of melanoma and open up the possibility of an anti-melanoma immunotherapy based on targeting CTLA-4 directly on tumour cells as this might allow inhibition of tumour cell growth and angiogenesis.

No significant financial relationships to disclose.

The role of oral fluoropyrimidines in the treatment of advanced gastric cancer

Although the incidence of gastric cancer is declining during the second half of the 20th century, it remains the second leading cause of cancer death worldwide. The majority of patients with gastric cancer will require palliative treatment at some point in the course of their disease. Approximately 50% of patients already have advanced incurable disease at the time of initial presentation, and even those who undergo potentially curative resection have high rates of distant as well as local recurrence. Chemotherapy in advanced gastric cancer demonstrated a significant survival benefit over best supportive care alone. Median overall survival increased from 3-5 to 8-12 months. Today, a platinum based regimen is considered as first-line treatment in advanced gastric cancer. Different regimens are investigated and used in routine practice. Similarly to fluorouracil, capecitabine is well tolerated in combination with a range of cytotoxic drugs. As a single agent, it has not undergone large scale randomised studies. S-1, another oral fluoropyrimidine, is a potential challenger to the role of capecitabine, but is lacking phase III data in Western population.