A mutation-based radiomics signature predicts response to imatinib in Gastrointestinal Stromal Tumors (GIST)

Objectives

To develop a mutation-based radiomics signature to predict response to imatinib in Gastrointestinal Stromal Tumors (GISTs).

Methods

Eighty-two patients with GIST were enrolled in this retrospective study, including 52 patients from one center that were used to develop the model, and 30 patients from a second center to validate it. Reference standard was the mutational status of tyrosine-protein kinase (KIT) and platelet-derived growth factor α (PDGFRA). Patients were dichotomized in imatinib sensitive (group 0 - mutation in KIT or PDGFRA, different from exon 18-D842V), and imatinib non-responsive (group 1 - PDGFRA exon 18-D842V mutation or absence of mutation in KIT/PDGFRA). Initially, 107 texture features were extracted from the tumor masks of baseline computed tomography scans. Different machine learning methods were then implemented to select the best combination of features for the development of the radiomics signature.

Results

The best performance was obtained with the 5 features selected by the ANOVA model and the Bayes classifier, using a threshold of 0.36. With this setting the radiomics signature had an accuracy and precision for sensitive patients of 82 % (95 % CI:60-95) and 90 % (95 % CI:73-97), respectively. Conversely, a precision of 80 % (95 % CI:34-97) was obtained in non-responsive patients using a threshold of 0.9. Indeed, with the latter setting 4 patients out of 5 were correctly predicted as non-responders.

Conclusions

The results are a first step towards using radiomics to improve the management of patients with GIST, especially when tumor tissue is unavailable for molecular analysis or when molecular profiling is inconclusive.

Effect of dose splitting of a low-volume bowel preparation macrogol-based solution on CT colonography tagging quality

Purpose

To compare examination quality and acceptability of three different low-volume bowel preparation regimens differing in scheduling of the oral administration of a Macrogol-based solution, in patients undergoing computed tomographic colonography (CTC). The secondary aim was to compare CTC quality according to anatomical and patient variables (dolichocolon, colonic diverticulosis, functional and secondary constipation).

Methods

One-hundred-eighty patients were randomized into one of three regimens where PEG was administered, respectively: in a single dose the day prior to (A), or in a fractionated dose 2 (B) and 3 days (C) before the examination. Two experienced radiologists evaluated fecal tagging (FT) density and homogeneity both qualitatively and quantitatively by assessing mean segment density (MSD) and relative standard deviation (RSD). Tolerance to the regimens and patient variables were also recorded.

Results

Compared to B and C, regimen A showed a lower percentage of segments with inadequate FT and a significantly higher median FT density and/or homogeneity scores as well as significantly higher MSD values in some colonic segments. No statistically significant differences were found in tolerance of the preparations. A higher number of inadequate segments were observed in patients with dolichocolon (p < 0.01) and secondary constipation (p < 0.01). Interobserver agreement was high for the assessment of both FT density (k = 0.887) and homogeneity (k = 0.852).

Conclusion

The best examination quality was obtained when PEG was administered the day before CTC in a single session. The presence of dolichocolon and secondary constipation represent a risk factor for the presence of inadequately tagged colonic segments.

Heat shock proteins in Varroa destructor exposed to heat stress and in-hive acaricides

Varroa destructor is one of the major pests that affect honeybees around the world. Chemical treatments are common to control varroosis, but mites possess biochemical adaptive mechanisms to resist these treatments, enabling them to survive. So far, no information is available regarding whether these pesticides can induce the expression of heat shock protein (Hsp) as a common protective mechanism against tissue damage. The aims of this study were to determine differences in heat shock tolerance between mites collected from brood combs and phoretic ones, and to examine patterns of protein expression of Hsp70 that occur in various populations of V. destructor after exposure to acaricides commonly employed in beekeeping, such as flumethrin, tau-fluvalinate and coumaphos. Curiously, mites obtained from brood cells were alive at 40 °C, unlike phoretic mites that reached 100% mortality, demonstrating differential thermo-tolerance. Heat treatment induced Hsp70 in mites 4 × more than in control mites and no differences in response were observed in phoretic versus cell-brood-obtained mites. Dose-response assays were carried out at increasing acaricide concentrations. Each population showed a different stress response to acaricides despite belonging to the same geographic region. In one of them, coumaphos acted as a hormetic stressor. Pyrethroids also induced Hsp70, but mite population seemed sensitive to this treatment. We concluded that Hsp70 could represent a robust biomarker for measuring exposure of V. destructor to thermal and chemical stress, depending on the acaricide class and interpopulation variability. This is relevant because it is the first time that stress response is analyzed in this biological model, providing new insight in host-parasite-xenobiotic interaction.

Short-term Arterial Blood Reperfusion of Normothermic Kidney in Renal Artery and Abdominal Aorta Reconstructive Surgery

OBJECTIVE

to prevent kidney injury in renal artery and juxta-renal aortic surgery. After 30 min of cross-clamping ischaemia, renal arterial inflow is temporary re-established for 3 min. The aim of the study was to retrospectively analyse the results of this original technique.

METHODS

between January 1987 and May 1999, 48 patients underwent kidney short-term arterial blood reperfusion, directly or through the Pruitt-Inahara shunt. The reperfusion was repeated every 30 min of ischaemia, whenever necessary. Fifty control patients underwent <30 min of kidney ischaemia. Patients were assessed by serum creatinine, digital angiography and radioisotope renography using technecium(99).

RESULTS

in the study group one patient developed an acute renal failure and died (2% (-95% CI: 0-11%)). In both study and control groups patients showed a similar and moderate but temporary decline in renal function, which returned to preoperative levels after 1 week.

CONCLUSIONS

the results of this study indicate that kidney short-term reperfusion may protect renal tissue from prolonged cross-clamping ischaemia (up to 100 min), also in patients considered at high risk for acute renal failure.

Carotid endarterectomy without angiography: a prospective randomised pilot study

OBJECTIVES

to determine whether duplex ultrasonography alone is an adequate examination prior to carotid endarterectomy.

DESIGN

prospective, randomised, single centre study.

MATERIAL AND METHODS

all patients with carotid bifurcation stenosis greater than 70% - based on duplex scanning - were randomised to arteriography followed by carotid surgery (Group A n=96) or carotid surgery alone (Group B n=90). Study endpoints were neurological complications or death occurring between the day of randomisation and until 30 days after surgery.

RESULTS

major neurological complications of death in 1 (1%) vs 3 (3.3%) patients in group A and B, respectively (n.s.). Minor neurological complications (only TIA) were observed in 0 and 3 (3.3%) patients, respectively.

CONCLUSIONS

complication rates were low in both groups and within the generally accepted rate after carotid surgery in asymptomatic and symptomatic patients.