Therapeutic targeting of constitutive PARP activation compromises stem cell phenotype and survival of glioblastoma-initiating cells

Glioblastoma-initiating cells (GICs) are self-renewing tumorigenic sub-populations, contributing to therapeutic resistance via decreased sensitivity to ionizing radiation (IR). GIC survival following IR is attributed to an augmented response to genotoxic stress. We now report that GICs are primed to handle additional stress due to basal activation of single-strand break repair (SSBR), the main DNA damage response pathway activated by reactive oxygen species (ROS), compared with non-GICs. ROS levels were higher in GICs and likely contributed to the oxidative base damage and single-strand DNA breaks found elevated in GICs. To tolerate constitutive DNA damage, GICs exhibited a reliance on the key SSBR mediator, poly-ADP-ribose polymerase (PARP), with decreased viability seen upon small molecule inhibition to PARP. PARP inhibition (PARPi) sensitized GICs to radiation and inhibited growth, self-renewal, and DNA damage repair. In vivo treatment with PARPi and radiotherapy attenuated radiation-induced enrichment of GICs and inhibited the central cancer stem cell phenotype of tumor initiation. These results indicate that elevated PARP activation within GICs permits exploitation of this dependence, potently augmenting therapeutic efficacy of IR against GICs. In addition, our results support further development of clinical trials with PARPi and radiation in glioblastoma.     

Respiratory epithelium inhibits bronchial smooth muscle tone

The aim of the present study was to determine whether or not the respiratory epithelium can modulate the responsiveness of bronchial smooth muscle. Paired rings of canine bronchi (4-6 mm OD), in some of which the epithelium had been removed mechanically (by rubbing the luminal surface), were mounted in physiological saline solution, gassed with 95% O2-5% CO2, and maintained at 37 degrees C. The presence or absence of the epithelium was confirmed by histological examination. Removal of the epithelium increased the contractile responses evoked by acetylcholine, histamine, and 5-hydroxytryptamine. Transmural nerve stimulation evoked similar peak responses in the presence and absence of epithelium. In unrubbed preparations, the peak response was followed by a gradual decrease when the stimulation was continued. This decrease, which persisted in the presence of propranolol, was not observed in epithelium-denuded preparations. In bronchial rings contracted with acetylcholine, isoproterenol produced concentration-dependent relaxations which were significantly greater in rings with epithelium compared with denuded rings. These results suggest that respiratory epithelial cells may generate an inhibitory signal to decrease the responsiveness of bronchial smooth muscle to contractile agonists and augment the effectiveness of inhibitory stimuli.     

Food resource allocation patterns in lactating females in a long-term selection experiment for litter size in mice

Resource allocation patterns, as quantified by residual food intake (RFI), and the consequences for offspring development were investigated during lactation in 96 females of a mouse line selected for 104 generations for high litter size at birth (S-line) and in 87 females of a non-selected control line (C-line). Litters of 45 C-line dams (Cs) and 48 S-line dams (Ss) were standardised (s) at birth; other dams (ns) supported total number of pups born (Cns and Sns, respectively). RFI during lactation was significantly lower in Sns-dams than in C-line dams and Sns-dams. After weaning Sns-dams seemed to be able to restore the negative resource situation. Sns-pups were about 25% less mature than Cns-pups at all times. Maturity was similar for Cs- and Ss-pups from 2 d in lactation on, and about 18% and 53% higher than Cns- and Sns-pups. The pre-weaning mortality rate was significantly higher in Sns-litters (35.6 ± 2.76) than in Cns-litters (4.95 ± 2.23). The results suggest that S-line dams allocated considerably more resources to maintenance of offspring than C-line dams. This was insufficient to provide the offspring with an adequate amount of resources, resulting in reduced pup development and increased pre-weaning mortality rates.     

Efficient, chemoselective synthesis of immunomicelles using single-domain antibodies with a C-terminal thioester

Background  

Classical bioconjugation strategies for generating antibody-functionalized nanoparticles are non-specific and typically result in heterogeneous compounds that can be compromised in activity. Expression systems based on self-cleavable intein domains allow the generation of recombinant proteins with a C-terminal thioester, providing a unique handle for site-specific conjugation using native chemical ligation (NCL). However, current methods to generate antibody fragments with C-terminal thioesters require cumbersome refolding procedures, effectively preventing application of NCL for antibody-mediated targeting and molecular imaging.     

Survival of <Emphasis Type="Italic">Listeria monocytogenes</Emphasis> in Wilted and Additive-Treated Grass Silage

Grass was field-dried to 3 different dry matter (DM) levels (200, 430 and 540 g/kg) and inoculated with 10⁶–10⁷ cfu/g of a Listeria monocytogenes strain sharing a phagovar occasionally involved in food-borne outbreaks of listeriosis. Formic acid (3 ml/kg) or lactic acid bacteria (8·10⁵/g) with cellulolytic enzymes were applied only to forages with low and intermediate DM levels. Forages were ensiled in laboratory silos (1700 ml) and were stored at 25°C for 30 or 90 days. After 90 days of storage, L. monocytogenes could not be detected in any silo, except one with the high dry matter grass without additive. After 30 days of storage, between 10² and 10⁶ cfu L. monocytogenes/g silage were isolated from the untreated silages. Increasing the DM content from 200 to 540 g/kg did not reduce listeria counts possibly because of the lower production of fermentation acids (higher pH). In silages treated with additives, counts of L. monocytogenes were always lower than in silages without additive. In wet silages (DM 200 g/kg) both additives were effective, but in the wilted silages (DM 430 g/kg) only the bacterial additive reduced listeria counts below detection level. Listeria counts were highly correlated to silage pH (r = 0.92), the concentration of lactic acid (r = -0.80) and the pooled amount of undissociated acids (r = -0.83).     

Ultrasound enhanced prehospital thrombolysis using microbubbles infusion in patients with acute ST elevation myocardial infarction: Rationale and design of the Sonolysis study

Background

The CONSORT Statement provides recommendations for reporting randomized controlled trials. We assessed the extent to which leading medical journals that publish reports of randomized trials incorporate the CONSORT recommendations into their journal and editorial processes.

Methods

This article reports on two observational studies. Study 1: We examined the online version of 'Instructions to Authors' for 165 high impact factor medical journals and extracted all text mentioning the CONSORT Statement or CONSORT extension papers. Any mention of the International Committee of Medical Journal Editors (ICMJE) or clinical trial registration were also sought and extracted. Study 2: We surveyed the editor-in-chief, or editorial office, for each of the 165 journals about their journal's endorsement of CONSORT recommendations and its incorporation into their editorial and peer-review processes.

Results

Study 1: Thirty-eight percent (62/165) of journals mentioned the CONSORT Statement in their online 'Instructions to Authors'; of these 37% (23/62) stated this was a requirement, 63% (39/62) were less clear in their recommendations. Very few journals mentioned the CONSORT extension papers. Journals that referred to CONSORT were more likely to refer to ICMJE guidelines (RR 2.16; 95% CI 1.51 to 3.08) and clinical trial registration (RR 3.67; 95% CI 2.36 to 5.71) than those journals which did not. Study 2: Thirty-nine percent (64/165) of journals responded to the on-line survey, the majority were journal editors. Eighty-eight percent (50/57) of journals recommended authors comply with the CONSORT Statement; 62% (35/56) said they would require this. Forty-one percent (22/53) reported incorporating CONSORT into their peer-review process and 47% (25/53) into their editorial process. Eighty-one percent (47/58) reported including CONSORT in their 'Instructions to Authors' although there was some inconsistency when cross checking information on the journal's website. Sixty-nine percent (31/45) of journals recommended authors comply with the CONSORT extension for cluster trials, 60% (27/45) for harms and 42% (19/45) for non-inferiority and equivalence trials. Few journals mentioned these extensions in their 'Instructions to Authors'.

Conclusion

Journals should be more explicit in their recommendations and expectations of authors regarding the CONSORT Statement and related CONSORT extensions papers.