Luciferase expression and bioluminescence does not affect tumor cell growth in vitro or in vivo

Live animal imaging is becoming an increasingly common technique for accurate and quantitative assessment of tumor burden over time. Bioluminescence imaging systems rely on a bioluminescent signal from tumor cells, typically generated from expression of the firefly luciferase gene. However, previous reports have suggested that either a high level of luciferase or the resultant light reaction produced upon addition of D-luciferin substrate can have a negative influence on tumor cell growth. To address this issue, we designed an expression vector that allows simultaneous fluorescence and luminescence imaging. Using fluorescence activated cell sorting (FACS), we generated clonal cell populations from a human breast cancer (MCF-7) and a mouse melanoma (B16-F10) cell line that stably expressed different levels of luciferase. We then compared the growth capabilities of these clones in vitro by MTT proliferation assay and in vivo by bioluminescence imaging of tumor growth in live mice. Surprisingly, we found that neither the amount of luciferase nor biophotonic activity was sufficient to inhibit tumor cell growth, in vitro or in vivo. These results suggest that luciferase toxicity is not a necessary consideration when designing bioluminescence experiments, and therefore our approach can be used to rapidly generate high levels of luciferase expression for sensitive imaging experiments.     

Improving behaviour in self-testing (IBIS): Study on frequency of use,consequences, information needs and use,and quality of currently available consumer information (protocol)

Background  

Self-tests are available to consumers for more than 25 conditions, ranging from infectious diseases to cardiovascular risk factors. Self-tests are defined as in-vitro tests on body materials such as blood, urine, faeces, or saliva that are initiated by consumers to diagnose a particular disorder or risk factor without involving a medical professional. In 2006, 16% of a sample of Dutch Internet users had ever used at least one self-test and 17% intended to use a self-test in the future. The objectives of this study are to determine (1) the frequency of self-test use, (2) the consumers' reasons for using or not using a self-test, (3) the information that is used by self-testers in the different self-test stages and the consumers' interpretation of the quality of this information, (4) the consumers' response to self-test results in terms of their confidence in the result, reassurance by the test result, and follow-up behaviour, (5) the information consumers report to need in the decision making process of using or not using a self-test, and in further management on the basis of the self-test result, and (6) the quality of the currently available consumer information on a selected set of self-tests.     

Rapid detection of pandemic influenza in the presence of seasonal influenza

Background  

Key to the control of pandemic influenza are surveillance systems that raise alarms rapidly and sensitively. In addition, they must minimise false alarms during a normal influenza season. We develop a method that uses historical syndromic influenza data from the existing surveillance system 'SERVIS' (Scottish Enhanced Respiratory Virus Infection Surveillance) for influenza-like illness (ILI) in Scotland.     

An audit of metal stent palliation for malignant biliary obstruction

BACKGROUND AND AIMS: Endoscopic stent insertion is the optimum method of palliation for malignant biliary obstruction. Metal stents have several advantages over the polyethylene alternatives, but are significantly more expensive. It has been reported that patients need to survive beyond 6 months to make metal stents more cost-effective. The aim of this study was to audit the performance of expanding metal biliary stents in our endoscopy unit, and to identify factors that might help with patient selection. METHODS: The records of all patients who were selected for endoscopic metal stent insertion at the Royal Perth Hospital for malignant biliary obstruction between September 1994 and November 1998 were reviewed. RESULTS: Thirty-two patients (16 males, mean age 71 years (range 34-88 years) were identified and followed up for a mean 201 days (range 3-810 days). Fifteen (47%) had cholangiocarcinoma, 13 (41%) had pancreatic cancer, and four had metastatic disease as the cause of obstruction. Mortality rates after metal stent insertion were 16, 41 and 55% at 30, 90 and 180 days, respectively. In total, 24 (75%) patients died during the follow-up period. Eleven (34%) stents became obstructed during follow up with a median time to occlusion of 125 days (range 44-729 days). Patients with cholangiocarcinoma had significantly longer survival than pancreatic cancer cases (median 286 vs 58 days, P = 0.04). No other factors were found to correlate with the survival or stent complications. CONCLUSIONS: Less than half of this mixed cohort survived beyond 6 months. Metal stent palliation of malignant biliary obstruction should probably be targeted at those with cholangiocarcinoma, as these patients tend to survive longer.     

Platelet storage pool deficiency in pigs

We report a new bleeding disease--storage pool deficiency (SPD) of platelets--in pigs from the Mayo swine colony of homozygous von Willebrand's disease (vWD) and of heterozygous carriers of vWD. Levels of factor VIII, von Willebrand factor antigen (vWF:Ag), and ristocetin cofactor (RCof) were similar in the vWD carriers and SPD pigs. The latter pigs, however, had bleeding times of 15 minutes or more and were severe bleeders, in contrast to clinically normal vWD carriers. Platelet aggregation in response to collagen was reduced in most SPD pigs. Total platelet content of ADP, ATP, and serotonin was less than that of normal pigs. While the initial uptake of 14C-labeled serotonin into platelets was similar in SPD and normal pigs, retention of serotonin was reduced in platelets of SPD pigs. Transmission electron microscopy showed a large decrease of dense bodies in the platelets of SPD pigs. These findings support a diagnosis of SPD. Genetic analyses suggest an autosomal recessive mode of inheritance. A breeding program is under way to produce pigs affected only at the SPD gene, thus allowing further characterization of SPD and SPD-carrier pigs.     

Constitutive expression of platelet glycoproteins by the human leukemia cell line K562

The human leukemia cell line K562 was derived from a patient with chronic granulocytic leukemia. This cell line has subsequently been shown to possess phenotypic markers typical of erythroid and myeloid cells. Using a rabbit antiserum directed against purified platelet glycoproteins (PGPs), we have obtained evidence for the constitutive expression of PGPs on the surface of K562 cells. PGPs expressed have been tentatively identified as IIa and III based on their apparent migration in a 7% sodium dodecylsulfate polyacrylamide gel. K562 may become an important tool for the study of early events involved in megakaryocytic differentiation.