Clinical outcome of patients with self-inflicted burns.

INTRODUCTION: Patients with self-inflicted burns (SIB) are thought to have a longer length of stay compared to patients with accidental burns. However, other predictors for a longer length of stay are often not taken into account, e.g. percentage of the body surface area burned, age or comorbidities. Therefore, we wanted to study the outcome of patients with SIB at our burn center. METHODS: A retrospective, observational study was conducted. All adult patients with acute burns admitted to the burn center of the Martini Hospital Groningen, between January 1, 2009 and December 31, 2013 were included. Data on characteristics of the patient, injury, and outcome (LOS, mortality, discharge destination) were collected. In patients with SIB, suicide attempts (SA) were distinguished from self-harm without the intention to die (non-suicidal self-injury, NSSI). To evaluate differences in outcome, each patient with SIB was matched on variables and total score of the Abbreviated Burn Severity Index (ABSI) to a patient with accidental burns (AB). RESULTS: In total 29 admissions (21 SA and 8 NSSI) were due to SIB and 528 due to accidents. Overall, when compared to AB, there were significant differences with respect to mortality and LOS for SA and/or NSSI. Mortality was higher in the SA group, while the LOS was higher in both the SA and NSSI groups compared to the AB group. However, after matching on ABSI, no statistical significant differences between the SA and SA-match or the NSSI and NSSI-match group were found. CONCLUSION: With the right and timely treatment, differences in mortality rate or length of stay in hospital could all be explained by the severity of the burn and the intention of the patient.

Mechanisms of enhancement of the antitumour activity of melphalan by the tumour-blood-flow inhibitor 5,6-dimethylxanthenone-4-acetic acid.

Several studies show that the antitumour activity of melphalan (MEL) and other alkylating agents can be enhanced by the selective inhibition of tumour blood flow, although the mechanism(s) underlying these interactions are unclear. 5,6-Dimethylxanthenone-4-acetic acid (DMXAA), a new anticancer agent currently in phase I clinical trial, inhibits blood flow in murine tumours. DMXAA increased the activity of MEL against the MDAH-MCa-4 mouse mammary tumour maximally when MEL was given about 2 h after DMXAA, without compromising the maximal dose of the alkylating agent that could be given. The plasma pharmacokinetics of MEL were unchanged by DMXAA pretreatment, but the area under the concentration-time curve (AUC) for the tumour increased by 33% as a result of decreasing clearance (consistent with falling tumour blood flow). However, inhibition of tumour blood flow also leads to microenvironmental changes (e.g. acidosis and hypoxia) that might influence sensitivity to MEL. The sensitivity of KHT cells (freshly isolated from tumours) to MEL in vitro was increased by lowering of either pH or oxygen concentration (pO2), with an overall dose-modifying factor of 15 being recorded for aerobic cells at pH 7.4 versus hypoxic cells at pH 6.5. The cellular uptake of MEL by KHT cells was increased by 74% under hypoxia. Thus, DMXAA appears to augment the antitumour activity of MEL through two different mechanisms, increased exposure (via decreased tumour clearance of MEL) and increased sensitivity resulting from changes to the tumour microenvironment, both of which result from inhibition of tumour blood flow.

Sigmoid neural transfer function realized by percolation.

An experiment using the phenomenon of percolation has been conducted to demonstrate the implementation of neural functionality (summing and sigmoid transfer). A simple analog approximation to digital percolation is implemented. The device consists of a piece of amorphous silicon with stochastic bit-stream optical inputs, in which a current percolating from one end to the other defines the neuron output, also in the form of a stochastic bit stream. Preliminary experimental results are presented.