Evaluation of plasma nucleosome concentrations in dogs with a variety of common cancers and in healthy dogs

Background

Cell free DNA, in the form of nucleosomes, is released into circulation during apoptosis and necrosis in a variety of diseases. They are small fragments of chromosomes that are composed of DNA wrapped around a histone core made of four duplicate histone proteins forming an octamer. The nucleosome compartment is a relatively uninvestigated area of circulating tumor biomarkers in dogs. The objectives of this study were to quantify and better characterize nucleosome concentrations in 528 dogs with various common malignancies and compare them to 134 healthy dogs.

Results

The sensitivity of increased circulating nucleosome concentrations for the detection of cancer in all dogs was 49.8% with a specificity of 97% with an area under the curve of 68.74%. The top 4 malignancies detected by the test included lymphoma, hemangiosarcoma, histiocytic sarcoma and malignant melanoma. The malignancies least likely to be detected were soft tissue sarcomas, osteosarcoma and mast cell tumors.

Conclusions

A variety of tumor types may cause increased nucleosome concentrations in dogs. Tumors of hematopoietic origin are most likely to cause elevations and local tumors such as soft tissue sarcomas are least likely to cause elevations in plasma nucleosome concentrations.

Understanding Thyroidectomy Cost Variations Among National Cancer Institute-Designated Cancer Centers

BACKGROUND

The cost of thyroidectomy varies across the USA, while the causes of this variation are poorly understood. We examined the cost of inpatient thyroidectomy among National Cancer Institute-designated cancer centers nationwide to determine why it differs.

METHODS

A retrospective study of inpatient thyroidectomies was performed using the Vizient Clinical Data Base. Fifty-two of 70 eligible hospitals were grouped into five geographic regions (Mid-Atlantic and New England, East Central, South Atlantic, West Central, and Mountain and Pacific). We identified drivers of cost variation in the five geographic regions and used risk adjustment model to evaluate the rationality of cost from each hospital.

RESULTS

Male sex, more extended hospital stays, and occurrence of complications were consistently associated with increased costs in all regions. Also, the cost was significantly lower in the Mid-Atlantic and New England region. The higher than expected costs did not correlate well with the case mix index among hospitals (p = 0.289), but the lower than expected costs were more common in high-volume hospitals. The average length of stay was the shortest in high-volume hospitals, which might account for the lower cost in the Mid-Atlantic and New England region; however, the overages of costs still varied widely among hospitals in all regions even if the length of stay was adjusted.

CONCLUSIONS

Cost variation may result from both patient-related factors and volume-related practice pattern differences among hospitals. A more standard of care and charge transparency is still needed for patients seeking affordable care at cancer centers.

Harnessing Behavioral Economics Principles to Promote Better Surgeon Accountability for Operating Room Cost: A Prospective Study

BACKGROUND

Operating room (OR) cost accounts for a significant portion of inpatient spending, but most surgeons are unaware of the costs of OR implants and supplies. We leveraged behavioral economics principles and a cost transparency tool to have an impact on discretionary OR spending (disposable supplies).

STUDY DESIGN

We performed a single-institution, prospective study, from January to December 2018, across 3 departments: urology, thoracic, and endocrine. Two self-selected procedures per department were subjected to intraoperative supply cost (ISC) feedback via a custom dashboard and monthly email reports. Behavioral economics principles like choice overload, social ranking, and threshold effects were leveraged during study design. The primary outcome of percentage change in the department-level mean ISC, as determined via an interrupted time-series mixed effects model, was compared between the intervention year (2018) and "pre-baseline" (2016) and "baseline" (2017) years.

RESULTS

A total of 2,853 procedures and 26 surgeons comprised our analytical sample. Costs decreased in 5 of the 6 procedures in 2018. On average, there was a significant monthly decrease in costs of approximately 0.5% over the study period (p = 0.0004). Post-intervention, there was a nonsignificant additional decrease of 0.6% in monthly cost (p = 0.0648). Overall cost significantly decreased by 20% due to the intervention (p < 0.0001). Similar results were noted on sensitivity analysis. There were no significant changes in the incidence of postoperative complication due to our intervention.

CONCLUSIONS

Deployment of a cost feedback tool using behavioral economics principles resulted in a significant decrease in OR spending without negatively affecting complication rate.

Surgeon perception versus reality: Opioid use after breast cancer surgery

BACKGROUND

Few guidelines exist for an opioid prescription after breast surgical oncology (BSO) procedures. We sought to characterize opioid prescribing and use patterns by surgery type.

METHODS

Patients (n = 332) undergoing BSO procedure were surveyed one week postoperatively for opioid use. The surgeons were surveyed about pain management preferences surgery type. CPT codes were collected for 2017 to calculate the amount of opioids used by surgery type relative to surgeon preference.

RESULTS

Mean oral morphine equivalent (OME) preferred prescription for surgeons who did not tailor prescriptions by surgery type (n = 7, group A) was 177, whereas for those who did tailor (n = 10, group B) varied from 137 to 257 OME. There was a significant difference in opioid use by surgery type: 32 OME for segmental mastectomy (SM) ± sentinel lymph node dissection (SLND), 63 for SM + axillary lymph node dissection (ALND), 76 for total mastectomy (TM) ± SLND, 115 for TM + ALND (P < 0.001). Considering the type of surgeries performed group A prescribers would have 229190 unused OME and group B would have 230826 in 1 year.

CONCLUSION

Wide variation in opioid use by BSO procedure type was noted with substantial unused OME regardless ofprescribing preference. Evidence-based guidelines are needed to tailor analgesic prescriptions according to the need.

Reassessing the environmental context of the Aitape Skull - The oldest tsunami victim in the world?

There is increasing recognition of the long-lasting effects of tsunamis on human populations. This is particularly notable along tectonically active coastlines with repeated inundations occurring over thousands of years. Given the often high death tolls reported from historical events though it is remarkable that so few human skeletal remains have been found in the numerous palaeotsunami deposits studied to date. The 1929 discovery of the Aitape Skull in northern Papua New Guinea and its inferred late Pleistocene age played an important role in discussions about the origins of humans in Australasia for over 25 years until it was more reliably radiocarbon dated to around 6000 years old. However, no similar attention has been given to reassessing the deposit in which it was found-a coastal mangrove swamp inundated by water from a shallow sea. With the benefit of knowledge gained from studies of the 1998 tsunami in the same area, we conclude that the skull was laid down in a tsunami deposit and as such may represent the oldest known tsunami victim in the world. These findings raise the question of whether other coastal archaeological sites with human skeletal remains would benefit from a re-assessment of their geological context.

SU-E-T-641: Flattening Filter Free Dynamic Conformal Arcs for Lung Radiotherapy

PURPOSE

To investigate the use of dynamic conformal arcs (DCA) with the flattening filter free (FFF) beams for lung stereotactic body radiotherapy (SBRT) on the TrueBeam STx (Varian, Inc., Palo Alto, CA).

METHODS

Eight SBRT patients receiving 10-18 Gy per fraction were planned in Eclipse 10 (Varian Medical Systems, Palo Alto, CA) for the TrueBeam STx using DCA's with 6 MV FFF beams. The isocenter was placed such that the point fell near midline on each patient allowing full arc rotation without patient collision.Several planning methods were employed depending on the location of the tumor. For peripheral tumors a single arc was used. For peripheral tumors with chestwall interference, additional oblique fields were used to help pull dose off of the chestwall. For tumors located in the central region or close to the spine, multiple DCA's were used. One standard open DCA was used to deliver the majority of the dose, then one or two additional DCA's with organs blocked automatically using the'Fit and Shield' feature of Eclipse were used to help shape the dose. The arcs were then weighted to create the desired dose distribution.

RESULTS

Beam on times for the 8 patients averaged 2.00 minutes with a minimum time of 1.22 minutes and a maximum time of 3.3 minutes total. With multiple arcs or additional static fields, treatment time is lengthened by the time it takes to mode up between arcs (∼1 minute) and/or move between fields. The PTV coverage of the 100% isodose line was >= 95% in all cases. The conformality index ranged 1.12 - 4.5, with an average of 2.5.

CONCLUSIONS

FFF DCA is a fast, efficient way to plan and delivery SBRT treatments. The short treatment times directly lead to reduced patient motion and discomfort, which may yield improved targeting and outcomes.

SU-E-T-304: Evaluation of Mammosite Multi-Lumen Rotation and Its Dosimetric Consequences

PURPOSE

To evaluate the dosimetric impact of MammoSite Multi-Lumen (MSML) rotation in phantom and patient studies.

METHODS AND MATERIALS

A MSML phantom with an asymmetric dose distribution was created. Target volume coverage and dose at a fixed point 1 cm from the MSML were evaluated as functions of rotation about three orthogonal axes (where the origin was set at the center of the MSML and axis one ran along the central catheter). Additionally, for three MSML patients that were set-up by aligning the stem of the MSML to skin marks, CT scans were acquired before each fraction. Rotation about three axes and maximum point dose to skin and chestwall were evaluated.

RESULTS

In phantom, 10° rotations about the central, second, and third axes give average absolute point dose changes with respect to the maximum dose of 1.9%, 3.7%, and 4.2%, respectively; and changes in PTV coverage of 0.9%, 1.0%., and 0.8%, respectively. For patients 1-3 the average absolute rotation about the central axis was 13.60, 9.50, and 7.20, respectively; axis two was 7.00, 3.20, and 11.40, respectively; axis three was 2.90, 2.90, and 3.80, respectively. For cases 1-3 the average absolute change per fraction in maximum point dose to the skin was 0.29 Gy, 0.14 Gy, and 0.39 Gy, respectively; to the chestwall was 0.17 Gy, 0.20 Gy, and 0.21 Gy, respectively.

CONCLUSION

Phantom studies showed change in point dose and PTV coverage for a 10° rotation about the central catheter yields < 2% variance. Patient data indicates skin mark alignment is capable of positioning the MSML with 10° accuracy about the central axis. Thus, central axis rotation can be adequately accounted for by skin mark alignment. However, review of the patient data shows that rotations about the other axes are equally important and should be considered and managed.

Extracranial optic nerve decompression: a 10-year review of 92 patients

Over a 10-year period the authors have performed 92 transethmoidal optic nerve decompressions for the treatment of visual loss due to various pathological processes, including 45 cases of trauma, 32 cases of neoplasm, 2 cases of bacterial pansinusitis, 5 cases of sphenoethmoidal mucocele, 4 cases of aspergillosis (all were immunocompetent patients), 2 cases of Wegener's granulomatosis, and 2 cases of sarcoidosis. Forty-eight patients (52%) had preoperative visual acuity of light perception or better, and in 44 patients (48%) the preoperative vision was no light perception. Sixty-five patients (71%) achieved improvement of vision postoperatively. Twenty-four patients (26%) had no change in vision and 3 patients (3%) had deterioration of vision after surgery. The mean percentage of improvement was 40.7% +/- 6.9% in the trauma group, 61.6% +/- 23.2% in the neoplasm group, 66.4% +/- 25.2% in the infectious/mucocele group, and only one patient in the inflammatory group had slight visual improvement from no light perception to counting fingers. Extracranial optic nerve decompression can result in the improvement of visual function in some patients with optic nerve injury from various causes.

22-Mb integrated physical and genetic map based on YAC/STS content spanning the interval DXS1125-DXS95 in human Xq12-q21.31

A YAC/STS map has been assembled spanning 22 Mb across Xq12-q21.31, between markers DXS1125 and DXS95. In addition to the landmark loci for the X-inactivation center XIST and the ATRX, ATP7A, phosphoglycerate kinase, POU3F4, and choroideremia genes, the candidate disease gene regions for torsion dystonia 3 and two X-linked mental retardation syndromes are included. Also, the human voltage-dependent anion channel gene (HVDAC1) has been placed near DXS986. The current map incorporates 211 YACs from five different libraries, formatted with 185 STSs that comprise 26 genetic linkage markers, 60 newly-developed YAC-end STSs, and eight ESTs. The multiple clone coverage and average resolution of one STS per 120 kb provide resources for disease gene searches and are facilitating complete sequencing of the region.

A function for monoubiquitination in the internalization of a G protein-coupled receptor

Modification of an S. cerevisiae G protein-coupled receptor with ubiquitin is required for its ligand-stimulated internalization. We now demonstrate that monoubiquitination on a single lysine residue is sufficient to signal receptor internalization, a modification distinct from that required for proteasome recognition. Formation of a polyubiquitin chain is not necessary, as demonstrated by the ability of mutant ubiquitins that lack lysine residues to serve as efficient internalization signals. Fusion of ubiquitin in-frame to a receptor that lacks cytoplasmic tail lysines also promotes rapid receptor internalization, indicating that ubiquitin itself and not a specific type of linkage to the receptor acts as an internalization signal. Thus, we have defined a cellular function for monoubiquitination in alpha-factor receptor endocytosis.

Evolutionary features of the 4-Mb Xq21.3 XY homology region revealed by a map at 60-kb resolution

Forty-three yeast artificial chromosomes (YACs) from the X chromosome have been overlapped across the 4-Mb Xq21.3 region, which is homologous to a segment in Yp11.1. The region is formatted to 60-kb resolution with 57 STSs and is merged at its edges with contigs specific for X. This allows a direct comparison of marker orders and distances on X and Y. In addition to some sequence variation and possible differences in marker order, two larger evolutionary divergencies between the X and Y homologs were revealed: (1) The X homolog is interrupted by a small X-specific region detected by a 3-kb plasmid probe for locus DXS214. An STS was developed from one end of the probe, but the sequence at the other end was highly homologous to an L1 repetitive element. This suggests that the interpolation of the X-specific segment may have involved an L1-mediated event. (2) A 250-kb portion containing DXYS1 is several megabases away from the rest of the homologous DNA on the Y but is contiguous with the remainder of the homologous region on X. Marker orders are consistent with the origin of the Y-specific 250-kb region in a paracentric inversion after the initial transfer of X DNA to the Y chromosome.

X chromosome map at 75-kb STS resolution, revealing extremes of recombination and GC content

A YAC/STS map of the X chromosome has reached an inter-STS resolution of 75 kb. The map density is sufficient to provide YACs or other large-insert clones that are cross-validated as sequencing substrates across the chromosome. Marker density also permits estimates of regional gene content and a detailed comparison of genetic and physical map distances. Five regions are detected with relatively high G + C, correlated with gene richness; and a 17-Mb region with very low recombination is revealed between the Xq13.3 [XIST] and Xq21.3 XY homology loci.

The effect of globe fixation on ablation zone centration in photorefractive keratectomy

PURPOSE

For optimal vision, the ablation zone in photorefractive keratectomy should be centered over the entrance pupil. During ablation, the globe can be immobilized by the surgeon, with a suction ring around the corneoscleral limbus. Alternatively, the globe can be immobilized by patient fixation on a target, unassisted by the surgeon. We investigated which method results in better centration of the ablation zone over the entrance pupil, by using an objective, mathematical method to determine the ablation zone center.

METHODS

Forty-eight eyes from 48 patients who underwent photorefractive keratectomy by the two techniques were studied retrospectively. The centers of the ablation zones were objectively determined by a weighted center of mass algorithm applied to the preoperative minus postoperative difference maps. The validity of the objective method was confirmed by comparison to subjective estimates of ablation zone centers made by independent human observers.

RESULTS

The 19 eyes treated by surgeon fixation had an average decentration of the ablation zone of 0.63 +/- 0.31 mm (range, 0.01 to 1.00 mm), and the 29 eyes treated by patient fixation had an average decentration of 0.41 +/- 0.23 mm (range, 0.11 to 1.18 mm) (P = .027).

CONCLUSIONS

The center of the ablation zone can be determined mathematically from the topographic map, to avoid observer bias. In this study, unassisted patient fixation during photorefractive keratectomy produced more accurate centration of the ablation zone than did surgeon fixation and has the potential for maximizing the quality of vision postoperatively.

Bovine retinal pigment epithelium promotes proliferation of choroidal endothelium in vitro

The invasion of Bruch's membrane and subsequently the subpigment epithelium and subretinal spaces by proliferating choroidal capillaries is a prominent feature of age-related macular degeneration. The ability to isolate and propagate pure cultures of bovine choroidal microvascular endothelium, choroidal pericytes, turbinate fibroblasts, and bovine retinal pigment epithelium allowed us to identify a growth-promoting activity produced by the retinal pigment epithelium that stimulated the proliferation of these cells in vitro. This mitogenic activity is present in both retinal pigment epithelium-conditioned medium and retinal pigment epithelium extract and enhances the mitogenic activity of retinal-derived extract. The activity is resistant to extremes of temperature and pH but partially sensitive to trypsin inactivation.

Localization of gamma glutamyl transpeptidase in bovine retina

Gamma-glutamyl transpeptidase (GGTP) is a membrane bound enzyme which has an important role in regulation of glutathione and glutamate in the retina. We have used histochemical and colorimetric enzyme assays to localize GGTP in the bovine retina and choroid. Our results demonstrate that (i) GGTP is present in retinal microvessels but not choroidal microvessels. (ii) Retinal microvascular endothelium loses the ability to express GGTP in cultured cells. (iii) GGTP is present in Muller cells. (iv) Isolated and purified rod outer segments contain high levels of GGTP. (v) Retinal pigment epithelial cells (RPE) in vivo and in culture contain GGTP. The findings of this study lend support to the concept that GGTP may be a biochemical marker for cellular systems which are part of specialized diffusion barriers.