A chasing dead-end case report: a fatal lead intoxication following an attempted homicide

Forensic Toxicology - In developed countries, lead intoxication is decreasing in adults as sources of contamination were considerably reduced. Hence, cases of lead encephalopathy have become...     

Salmonid alphavirus glycoprotein E2 requires low temperature and E1 for virion formation and induction of protective immunity

Salmonid alphavirus (SAV; also known as Salmon pancreas disease virus; family Togaviridae) causes pancreas disease and sleeping disease in Atlantic salmon and rainbow trout, respectively, and poses a major burden to the aquaculture industry. SAV infection in vivo is temperature-restricted and progeny virus is only produced at low temperatures (10–15 °C). Using engineered SAV replicons we show that viral RNA replication is not temperature-restricted suggesting that the viral structural proteins determine low-temperature dependency. The processing/trafficking of SAV glycoproteins E1 and E2 as a function of temperature was investigated via baculovirus vectors in Sf9 insect cells and by transfection of CHSE-214 fish cells with DNA constructs expressing E1 and E2. We identified SAV E2 as the temperature determinant by demonstrating that membrane trafficking and surface expression of E2 occurs only at low temperature and only in the presence of E1. Finally, a vaccination-challenge model in Atlantic salmon demonstrates the biological significance of our findings and shows that SAV replicon DNA vaccines encoding E2 elicit protective immunity only when E1 is co-expressed. This is the first study that identifies E2 as the critical determinant of SAV low-temperature dependent virion formation and defines the prerequisites for induction of a potent immune response in Atlantic salmon by DNA vaccination.     

Semiparametric methods for multistate survival models in randomised trials

Transform methods have proved effective for networks describing a progression of events. In semi‐Markov networks, we calculated the transform of time to a terminating event from corresponding transforms of intermediate steps. Saddlepoint inversion then provided survival and hazard functions, which integrated, and fully utilised, the network data. However, the presence of censored data introduces significant difficulties for these methods. Many participants in controlled trials commonly remain event‐free at study completion, a consequence of the limited period of follow‐up specified in the trial design. Transforms are not estimable using nonparametric methods in states with survival truncated by end‐of‐study censoring. We propose the use of parametric models specifying residual survival to next event. As a simple approach to extrapolation with competing alternative states, we imposed a proportional incidence (constant relative hazard) assumption beyond the range of study data. No proportional hazards assumptions are necessary for inferences concerning time to endpoint; indeed, estimation of survival and hazard functions can proceed in a single study arm. We demonstrate feasibility and efficiency of transform inversion in a large randomised controlled trial of cholesterol‐lowering therapy, the Long‐Term Intervention with Pravastatin in Ischaemic Disease study. Transform inversion integrates information available in components of multistate models: estimates of transition probabilities and empirical survival distributions. As a by‐product, it provides some ability to forecast survival and hazard functions forward, beyond the time horizon of available follow‐up. Functionals of survival and hazard functions provide inference, which proves sharper than that of log‐rank and related methods for survival comparisons ignoring intermediate events. Copyright © 2013 John Wiley & Sons, Ltd.     

Does Self-Selection Affect Samples’ Representativeness in Online Surveys? An Investigation in Online Video Game Research

Background

The number of medical studies performed through online surveys has increased dramatically in recent years. Despite their numerous advantages (eg, sample size, facilitated access to individuals presenting stigmatizing issues), selection bias may exist in online surveys. However, evidence on the representativeness of self-selected samples in online studies is patchy.

Objective

Our objective was to explore the representativeness of a self-selected sample of online gamers using online players’ virtual characters (avatars).

Methods

All avatars belonged to individuals playing World of Warcraft (WoW), currently the most widely used online game. Avatars’ characteristics were defined using various games’ scores, reported on the WoW’s official website, and two self-selected samples from previous studies were compared with a randomly selected sample of avatars.

Results

We used scores linked to 1240 avatars (762 from the self-selected samples and 478 from the random sample). The two self-selected samples of avatars had higher scores on most of the assessed variables (except for guild membership and exploration). Furthermore, some guilds were overrepresented in the self-selected samples.

Conclusions

Our results suggest that more proficient players or players more involved in the game may be more likely to participate in online surveys. Caution is needed in the interpretation of studies based on online surveys that used a self-selection recruitment procedure. Epidemiological evidence on the reduced representativeness of sample of online surveys is warranted.     

The amino terminus of the salmonid alphavirus capsid protein determines subcellular localization and inhibits cellular proliferation

Salmonid alphavirus (SAV) is the most divergent member of the family Togaviridae and constitutes a threat to farming of salmonid fish in Europe. Here, we report cloning, expression and preliminary functional analysis of the capsid protein of SAV, confirming it to be expressed as an approximately 31-kDa protein in infected cells. The protein localizes strictly to the cytoplasm in Chinook salmon embryo cells, and either to the nucleus or cytoplasm in bluegill fry cells. An expression study of full-length and different truncated versions of the SAV capsid fused to the enhanced green fluorescent protein demonstrated that the localization is independent of other viral components in both cell lines, and controlled by the N-terminal 82 aa, which include a conserved, predicted helix and a downstream positively charged region. Thus, the results suggest that the SAV capsid possesses a cell-type-dependent potential for nuclear import and export. Moreover, the SAV capsid and its N-terminal 82 aa were shown to be associated with inhibition of cellular proliferation, a hallmark of the cytopathic effect caused by SAV. These results highlight that the SAV capsid is a multifunctional protein with possible importance for pathogenesis.     

A phase I trial of pre-operative radiotherapy for prostate cancer: Clinical and translational studies

BACKGROUND AND PURPOSE: Selected patients undergoing radical prostatectomy for localized prostate cancer can be at high-risk for pT3 disease and require subsequent radiotherapy. In a phase I trial, we investigated the feasibility of pre-operative radiotherapy for this patient subset. MATERIALS AND METHODS: Eligibility criteria were: T1/T2N0M0 tumors plus (i) Gleason >or=7, PSA>10 ng/ml and <35 ng/ml, or (ii), PSA >15 ng/ml and less <35 ng/ml (any Gleason). Patients received 25 Gy in five fractions of radiotherapy followed by radical prostatectomy. Trial endpoints included intra-operative morbidity and late toxicity following combined treatment. We also stained pre- and post-radiotherapy prostate samples for DNA damage response proteins. RESULTS: Between 2001 and 2004, 15 patients were entered on trial. Thirteen patients completed combined-modality treatment. Only one patient had signs of intra-operative inflammation. No patient had post-operative complication. There was no severe late gastrointestinal toxicity. Late genitourinary toxicity consisted of severe urinary incontinence in 2 of 13 patients. From a translational standpoint, irradiated prostate tumor tissues had long-term activation of the CDK-inhibitor p21(WAF) associated with reduced cell proliferation. CONCLUSION: Intra-operative morbidity is low following short-course, pre-operative radiotherapy. A phase II trial is planned to fully document biochemical response with this combined-modality approach.     

In Vivo Reversal of Multidrug Resistance by Two New Dihydropyridine Derivatives, S16317 and S16324

Two new dihydropyridine derivatives with low calcium channel affinity, S16317 and S16324, were found to fully overcome multidrug resistance in vitro. These two compounds increased doxorubicin cytotoxicity on the human COLO 320DM cell line and completely reversed the vincristine resistance of murine P388/VCR cells. In vivo, S16324 administered p.o. (200 mg/kg on days 1 to 4) or i.p. (50mg/kg on days 1, 5, 9) in combination with vincristine (i.p.) restored the antitumor activity of vincristine in P388/VCR-bearing mice. S16317 showed a reversing activity when administered p.o., i.v. (days 1 to 4) or i.p. (days 1, 5, 9) at the same dose (25 mg/kg), suggesting a remarkable bioavailability. Moreover, these two compounds potentiated the antitumor activity of vincristine in the sensitive P388 leukemia, increasing the number of long-term survivors. These results suggest that combination chemotherapy using S16317 or S16324 would be effective not only in circumventing multidrug resistance but also in preventing the emergency of a population of resistant tumor cells in sensitive tumors.