Gamma Knife Radiosurgery of Brain Metastasis from Malignant Pleural Mesothelioma : Report of Three Cases with Autopsy Study in a Case

2014-02The median survival time of malignant pleural mesothelioma (MPM) has been 9 months. Given the short survival, there have been only few cases in which brain metastases have been diagnosed and treated before death. Three cases of brain metastases treated by gamma knife radiosurgery (GKR) are reported. Case 1 showed a metastatic lesion in the right frontal lobe which was treated by GKR two years after diagnosis of MPM. The lesion markedly reduced and the symptoms were improved, But the patient died of progression of pleural tumor four months after GKR. A year and three months after the diagnosis, asymptomatic bifrontal lesions were treated with GKR. However, Case 2 died of abdominal mass a month after. Case 3 showed headache one and half year after the diagnosis. Three brain lesions were treated by GKR, which disappeared in 4 months. The patient died of new multiple brain metastases and periventricular dissemination seven months after. The autopsy revealed a MPM occupying the left pleural cavity. No neoplastic lesion was found in gamma knife-treated sites. The cause of death was the mass effect by new metastatic lesions. GKR was found effective also for the treatment of brain metastasis of MPM.departmental bulletin pape

Drug Export Pathway of Multidrug Exporter AcrB Revealed by DARPin Inhibitors - Table 1

Data Collection and Refinement Statistics</p

Channels in the AcrB Trimer

<p>Stereo view of the channels leading through the periplasmic domain of AcrB. The structure of AcrB is shown as wire model and the DARPins omitted for clarity. The channels are shown as blue surfaces and were calculated using the program CAVER (<a href="http://loschmidt.chemi.muni.cz/caver" target="_blank">http://loschmidt.chemi.muni.cz/caver</a>).</p

Schematic Drawing of the Transport Pathway of the AcrB Efflux Pump Suggesting a Rotary Mechanism

<p>Proposed mechanism: Substrate may bind into the channel through the open entrances of subunit B. Helix 8 is only weakly pronounced and mostly random coil. Changes of the protonation state of residues of the putative translocation site induce the formation of helix 8 and thus the closing of the channel entrances and the simultaneous opening of the gate, extending the channel to the central funnel at the top of the headpiece showing the conformation of subunit C. The bound substrate can be released into the central funnel from where it reaches TolC and finally the cell exterior. Deprotonation takes place, leading to the collapse of helix 8, and the channel goes back to the original conformation (subunit A).</p

Conformational Changes in the TM Region of AcrB

<p>(A) Wire model of the superpositioned TM domains of subunit A and subunit C viewed from the periplasmic side. Subunit B is omitted since it displays a similar conformation as subunit A. The individual helices are labeled.</p> <p>(B) Detailed interactions of the amino acid residues in the putative proton-translocation site viewed in the same orientation as in (A). Residues involved in the hydrogen-bonded network (dashed lines) are labeled. The |F<i>o</i>-F<i>c</i>| omit electron density map (blue mesh) of Lys940 in subunit C is contoured at 3.5 σ.</p

Phenotype of E. coli XL1-Blue Strain Expressing the Selected Inhibitory DARPins

<p>Six AcrB inhibitors (2907_5, 1108_5, 1108_6, 1108_9, 1108_19, and A11), one unselected nonbinding DARPin (E3_5), and an <i>acrB</i> knockout strain (KAM3 [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050007#pbio-0050007-b014" target="_blank">14</a>], transformed also with E3_5) were ranked for their R6G sensitivity. Induction of the DARPins results in the inhibition of AcrB, yielding an R6G-sensitive phenotype. E. coli cells were transformed with the respective plasmid and plated under different conditions: nonselective, no R6G or no IPTG; selective where different R6G concentrations create an environment in which inhibitory DARPins repress growth. All plates contained IPTG (except plate no IPTG). The plates were colored with Coomassie brilliant blue for better visibility of the colonies.</p

The Extension of the Channels in the Individual Subunits of AcrB

<p>The view is the same as in <a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050007#pbio-0050007-g002" target="_blank">Figure 2</a>A. For simplicity, the DARPins are not shown. The channels are colored in transparent blue. The potential export pathway is represented by dashed lines. The loop forming the bottom of the periplasmic channel entrance (PE) and TM helix 8 are highlighted in red. The gate to the central funnel formed by the residues Gln124, Gln125, and Tyr758 is shown in space filling representation for clarity.</p> <p>(A) In subunit A, the channel is opened to the periplasm, while the gate is in the closed conformation. The pore domain subdomains are labeled.</p> <p>(B) In subunit B, the channel displays an open conformation to the periplasm and to the membrane bilayer (CE). The gate is in a closed conformation.</p> <p>(C) Subunit C displays a closed conformation of the channel entrances, while the gate is open, extending the channel to the central funnel.</p

Crystal Structure of the AcrB–DARPin Complex

<p>(A) Ribbon diagram of the overall AcrB–DARPin complex structure viewed from the side, depicted in three different colors for each subunit: green, blue, and yellow for A, B, and C, respectively. The DARPins are colored in red. This color code is used throughout all the figures. The locations of the three prominent domains are indicated and the important regions are highlighted and labeled in subunit C (G, gate; ED, external depression; P, putative proton translocation site; H, helix 8).</p> <p>(B) Ribbon diagram of the overall AcrB–DARPin complex viewed from the periplasm.</p> <p>(C) Ribbon diagram of the pore domain viewed as in (B). The subdomains are labeled.</p> <p>All figures of the molecular models were generated with PyMOL [<a href="http://www.plosbiology.org/article/info:doi/10.1371/journal.pbio.0050007#pbio-0050007-b031" target="_blank">31</a>].</p