Potential for a minor pine bark beetle pest, Dendroctonus terebrans (Coleoptera: Curculionidae: Scolytinae), to mediate host location by a major pine killer, Dendroctonus frontalis

The southern pine beetle, Dendroctonus frontalis Zimmermann is an important mortality agent of Pinus in the eastern United States of America where it commonly shares hosts with the black turpentine beetle, Dendroctonus terebrans (Olivier), which infrequently kills trees. Unlike D. frontalis, which must kill its hosts to become established in the bark and reproduce, D. terebrans can occupy living hosts as a parasite. Olfactory mechanisms whereby D. frontalis initially locates hosts have not been demonstrated, whereas D. terebrans responds strongly to host odors. Because D. terebrans produces frontalin, the primary aggregation pheromone component for D. frontalis, and commonly arrives on hosts prior to D. frontalis, it has been hypothesized that D. terebrans pheromone components can mediate D. frontalis location of suitable, living trees. We assessed this possibility with studies of the semiochemical interactions between D. frontalis and D. terebrans. Coupled gas chromatography-electroantennographic detection analyses indicated that D. terebrans produces nine different olfactory stimulants for D. frontalis, nearly all of them known semiochemicals for D. frontalis. A trapping experiment designed to address the potentially confounding influence of lure contamination confirmed that the D. terebrans pheromone component exo-brevicomin enhances attraction of D. frontalis and thus could be an attractive kairomone. In ambulatory bioassays, male D. frontalis were strongly attracted to odors of frass of solitary female and paired D. terebrans, indicating their attraction to the naturally occurring semiochemicals of D. terebrans. Cues from D. terebrans may influence host and mate-finding success of D. frontalis and, thereby, the latter's virulence.

Optical filter wavefront distortion: out-of-band to in-band predictions and the effect of the illumination source bandwidth

The wavefront distortion (WFD) of a surface with an optical filter coating is ideally measured at the operating wavelength (λ) and angle of incidence (θ) of the filter. However, this is not always possible, requiring that the filter be measured at an out-of-band wavelength and angle (typically λ=633n m and θ=0^∘). Since the transmitted wavefront error (TWE) and reflected wavefront error (RWE) can depend on the measurement wavelength and angle, an out-of-band measurement may not give an accurate characterization of the WFD. In this paper, we will show how to predict the wavefront error (WFE) of an optical filter at the in-band wavelength and angle from a WFE measurement at an out-of-band wavelength and different angle. This method uses (i) the theoretical phase properties of the optical coating, (ii) the measured filter thickness uniformity, and (iii) the substrate's WFE dependence versus the angle of incidence. Reasonably good agreement was achieved between the RWE measured directly at λ=1050n m (θ=45^∘) and the predicted RWE based on an RWE measurement at λ=660n m (θ=0^∘). It is also shown through a series of TWE measurements using a light emitting diode (LED) and laser light sources that, if the TWE of a narrow bandpass filter (e.g., an 11 nm bandwidth centered at λ=1050n m) is measured with a broadband LED source, the WFD can be dominated by the chromatic aberration of the wavefront measuring system-hence, a light source that has a bandwidth narrower than the optical filter bandwidth should be used.

Is an Orthopaedic Surgery Resident's Previous Case Experience Associated with Success of Initial Treatment of Pediatric Forearm Fractures?

Redisplacement and subsequent intervention are common for pediatric forearm fractures. We investigated associations between the success of closed reduction and the treating provider's experience. We identified patients aged 4-16 years with forearm fractures treated by closed reduction and cast immobilization. Clinical data and radiographs of 130 patients treated by 30 residents were reviewed to determine the treating resident's pediatric forearm fracture reduction experience and the incidence of initial treatment failure (ITF). ITF was defined as subsequent intervention before union or malunion. ITF occurred in 32 of 130 patients (25%), comprising 12 of 23 patients (52%) treated by residents with no previous experience and 20 of 107 patients (19%) treated by residents who had logged ≥ 1 previous reduction (odds ratio, 4.7). ITF was more likely to occur in pediatric forearm fractures treated by residents with no previous forearm reduction experience compared with those performed by residents who had such experience. Level of Evidence: Level III, therapeutic. (Journal of Surgical Orthopaedic Advances 32(1):032-035, 2023).

The Role of Wind and Semiochemicals in Mediating Switching Behavior in the Southern Pine Beetle (Coleoptera: Curculionidae: Scolytinae)

Aggressive bark beetles colonize and kill healthy conifers through pheromone-mediated mass aggregation. In several species, the focal point of aggregation moves progressively from mass-attacked 'focus trees' to adjacent, unattacked 'recipient trees', resulting in infestation growth. This process, termed 'switching', is hypothesized to be mediated in whole or in part by antiaggregation pheromones released by beetles as colonization intensifies on a focus tree. We tested this hypothesis with the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae), by using a windvane apparatus that maintained an unbaited, black, cylindrical trap (surrogate for a recipient tree) continuously 4 m downwind from an identical trap baited with synthetic aggregation attractant (surrogate for a focus tree). In two of three replicated trials, addition of pheromone components with antiaggregation activity, endo-brevicomin or verbenone, to the upwind trap caused a significant but small (<15%) increase in the proportion of beetles caught in the downwind trap. In one of two trials with endo-brevicomin, this shift was associated with a significant reduction in catches in the downwind trap and an overall reduction in catches of beetles by the trap pair. This suggests that an inhibitor-induced increase in landings on the recipient relative to the focus tree may be countered by the radial effects of the inhibitor, which at sufficiently high release may reduce responses to both the focus and recipient tree. We discuss spatial factors that might govern the role of antiaggregation pheromones in stimulating infestation growth as well as additional factors that likely govern switching behavior.

Are We Working Harder for Less Pay? A Survey of Medicare Reimbursement for Hand and Upper Extremity Surgery

BACKGROUND

Ongoing concern for declining Medicare payment to surgeons may incentivize surgeons to perform more cases to maintain productivity goals. The authors evaluated trends in physician payment, patient charges, and reimbursement ratios for the most common hand and upper extremity surgical procedures.

METHODS

The authors examined Medicare surgeon payment, patient charges, and surgical volume from 2012 to 2017 for 83 common surgical procedures, incorporating the year-to-year Consumer Price Index to adjust for inflation. The reimbursement ratio was calculated by dividing payment by charge. Weighted (by surgery type and volume) averages were calculated.

RESULTS

Total Medicare surgeon payment increased 5.6 percent to $272 million for the studied procedures. Patient charges were seven times greater than payment, growing 24 percent to $1.9 billion. Despite growth of total payment, the average overall weighted payment for a single surgery decreased 3.5 percent. The average weighted patient charge increased 8 percent, whereas the reimbursement ratio decreased 13 percent. A hand surgeon would need to perform three more cases per 100 in 2017 to maintain the same reimbursement received in 2012. After categorizing these 83 surgical procedures, distal radius fixation (>3 parts, 21 percent increase; >2-part intra-articular, extra-articular, and percutaneous pinning, 17 percent increase), bony trauma proximal to the distal radius (10 percent increase), and upper extremity flap (5 percent increase) were subject to the greatest increases in payment. Payment for forearm fasciotomy (39 percent decrease), endoscopic carpal tunnel release (30 percent decrease), and mass excisions proximal to the wrist (18 percent decrease) decreased the most.

CONCLUSIONS

From 2012 to 2017, despite a disproportionate increase in procedure charges, Medicare surgeon payment has not decreased substantially; however, total reimbursement is multifactorial and involves multiple sources of revenue and cost.

Some Effects of endo-Brevicomin Background on Southern Pine Beetle (Coleoptera: Curculionidae: Scolytinae) Aggregation Behavior

Semiochemical background in the environment can influence insect orientation to release points of the same or different semiochemicals. endo-Brevicomin is a pheromone component of the tree-killing bark beetle Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) that has a biphasic dose-response curve, enhancing attraction at low release rates but reducing attraction at high rates. We investigated the effect of artificial manipulation of background levels of endo-brevicomin on D. frontalis responses to sources of aggregation attractant in the field. Traps baited with the aggregation pheromone component frontalin and the host odor alpha-pinene were deployed either with or without a background of endo-brevicomin produced by three surrounding dispensers of this semiochemical each located 20 m away. Two tested levels of endo-brevicomin background caused catches to increase by an order of magnitude above those in the absence of background. Presence of background also altered the beetles' biphasic dose-response when endo-brevicomin dispensers were added to traps. Background reduced or concealed attraction-enhancement otherwise observed for low-release dispensers added to traps, and it decreased the release rate necessary to produce reductions in catches. We propose that spatial variability in abundance of natural, background sources of endo-brevicomin in the environment (i.e., infested trees) is a cause of the observed variability in effects of endo-brevicomin dispensers on southern pine beetle behavior in the field. Furthermore, our results illustrate the potential complexity of the density-dependent effects of biphasic pheromone components on bark beetle mass attack and colonization behavior.

Alternative Formulations of Trap Lures for Operational Detection, Population Monitoring, and Outbreak Forecasting of Southern Pine Beetle in the United States

The southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) is a major destructive pest of Pinus L. In the southeastern United States, numbers of this species and a major predator, Thanasimus dubius (Fabricius) (Coleoptera: Cleridae), captured during an annual springtime trapping survey are used to make forecasts of the likelihood and severity of an outbreak during the following summer. We investigated responses by both species to six lure formulations to evaluate their suitability for the survey and allow integration of historical data sets produced with differing lure compositions. Trapping trials were performed at four locations across three states (Louisiana, Mississippi, and Alabama) during spring, and at these and one additional location (North Carolina) in fall 2016. All lures included the pheromone component frontalin. Southern pine beetle preferred lures that additionally included the pheromone component endo-brevicomin and turpentine as a source of host odors (rather than a 7:3 mixture of monoterpenes alpha- and beta-pinene). Thanasimus dubius displayed little discrimination among lure compositions. Lure preferences by southern pine beetle did not differ significantly among locations in spring but were influenced by season. Gas chromatography (GC)-electroantennographic detection analyses with southern pine beetle and GC-mass spectrometry identified numerous known and potential semiochemicals that distinguished volatiles released by the tested host odor devices. The lure combination that included endo-brevicomin and alpha/beta-pinene is recommended for the trapping survey because of its high sensitivity for southern pine beetle and potential for greater data integrity resulting from its reproducible composition.

Using the Remnant Anterior Cruciate Ligament to Improve Knee Stability: Biomechanical Analysis Using a Cadaveric Model

Background:

Injured anterior cruciate ligament (ACL) tissue retains proprioceptive nerve fibers, vascularity, and biomechanical properties. For these reasons, remnant ACL tissue is often preserved during the treatment of ACL injuries.

Purpose:

To assess through a cadaveric model whether reorienting and retensioning the residual ACL via an osteotomy improves knee stability after partial ACL tear, with substantial remnant tissue and intact femoral and tibial attachments.

Study Design:

Controlled laboratory study.

Methods:

In 8 adult cadaveric knees, we measured anterior tibial translation and rotational laxity at 30° and 90° of flexion with the ACL in its native state and in 3 conditions: partial tear, retensioned, and ACL-deficient. The partial-tear state consisted of a sectioned anteromedial ACL bundle.

Results:

In the native state, the translation was 10 ± 2.7 mm (mean ± SD) at 30° of flexion and 8.4 ± 3.6 mm at 90° of flexion. Anterior translation of the knees in the partial-tear state (14 ± 2.7 mm at 30° and 12 ± 2.7 mm at 90°) was significantly greater than baseline (P < .001 for both). Translation in the ACL-retensioned state (9.2 ± 1.7 mm at 30° and 7.2 ± 2.1 mm at 90°) was significantly less than in the ACL-deficient state (P < .001 for both), and translation was not significantly different from that of the intact state. For ACL-deficient knees, translation (20 ± 4.3 mm at 30° and 16 ± 4.4 mm at 90°) was significantly greater than all other states (P < .001 for all). Although rotational testing demonstrated the least laxity at 30° and 90° of flexion in the retensioned and intact states and the most laxity in the ACL-deficient state, rotation was not significantly different among any of the experimental states.

Conclusion:

In a cadaveric model of an incomplete ACL tear, a reorienting and retensioning core osteotomy at the tibial insertion of the remnant ACL improved anteroposterior translation of the knee without compromising its rotational laxity.

Clinical Relevance:

The findings of this study support the concept of ACL tissue reorienting and retensioning in the treatment of ACL laxity as an area for future investigation.

Effect of an optical coating on in-band and out-of-band transmitted and reflected wavefront error measurements

The wavefront error (WE) of a surface with an optical coating ("filter") is ideally measured at the in-band wavelength of the filter. However, quite often this is not possible, requiring that the filter be measured at an out-of-band wavelength (typically 633 nm), assuming that the filter transmits (for transmitted WE, or TWE) or reflects (for reflected WE, or RWE) at this wavelength. This out-of-band TWE/RWE is generally assumed to provide a good estimation of the desired in-band TWE/RWE. It will be shown in this paper that this is not the case for a large class of filters (i.e., bandpass) where the group delay is significantly different at the in-band and out-of-band wavelengths and where the optical filter exhibits a thickness non-uniformity across the surface. A theoretical explanation will be given along with an approach to predict the in-band TWE/RWE based on the coating non-uniformity, the measured out-of-band TWE/RWE, and the theoretical properties of the optical filter at the in-band and out-of-band wavelengths. A reasonable agreement between theory and measurement was demonstrated by measuring the TWE of an 11 nm wide bandpass filter (centered at 1048 nm) at both in-band (λ=1048nm) and out-of-band (λ=625nm) wavelengths. A similar treatment is provided for RWE.

A Novel Peer-Directed Curriculum to Enhance Medical Ethics Training for Medical Students: A Single-Institution Experience

BACKGROUND

The best pedagogical approach to teaching medical ethics is unknown and widely variable across medical school curricula in the United States. Active learning, reflective practice, informal discourse, and peer-led teaching methods have been widely supported as recent advances in medical education. Using a bottom-up teaching approach builds on medical trainees' own moral thinking and emotion to promote awareness and shared decision-making in navigating everyday ethical considerations confronted in the clinical setting.

OBJECTIVE

Our study objective was to outline our methodology of grassroots efforts in developing an innovative, student-derived longitudinal program to enhance teaching in medical ethics for interested medical students.

METHODS

Through the development of a 4-year interactive medical ethics curriculum, interested medical students were provided the opportunity to enhance their own moral and ethical identities in the clinical setting through a peer-derived longitudinal curriculum including the following components: lunch-and-learn didactic sessions, peer-facilitated ethics presentations, faculty-student mentorship sessions, student ethics committee discussions, hospital ethics committee and pastoral care shadowing, and an ethics capstone scholarly project. The curriculum places emphasis on small group narrative discussion and collaboration with peers and faculty mentors about ethical considerations in everyday clinical decision-making and provides an intellectual space to self-reflect, explore moral and professional values, and mature one's own professional communication skills.

RESULTS

The Leadership through Ethics (LTE) program is now in its fourth year with 14 faculty-clinician ethics facilitators and 65 active student participants on track for a distinction in medical ethics upon graduation. Early student narrative feedback showed recurrent themes on positive curricular components including (1) clinician mentorship is key, (2) peer discussion and reflection relatable to the wards is effective, and (3) hands-on and interactive clinical training adds value. As a result of the peer-driven initiative, the program has been awarded recognition as a graduate-level certification for sustainable expansion of the grassroots curriculum for trainees in the clinical setting.

CONCLUSIONS

Grassroots medical ethics education emphasizes experiential learning and peer-to-peer informal discourse of everyday ethical considerations in the health care setting. Student engagement in curricular development, reflective practice in clinical settings, and peer-assisted learning are strategies to enhance clinical ethics education. The Leadership through Ethics program augments and has the potential to transform traditional teaching methodology in bioethics education for motivated students by offering protected small group discussion time, a safe environment, and guidance from ethics facilitators to reflect on shared experiences in clinical ethics and to gain more robust, hands-on ethics training in the clinical setting.

Deep Infections After Pediatric Spinal Arthrodesis: Differences Exist with Idiopathic, Neuromuscular, or Genetic and Syndromic Cause of Deformity

BACKGROUND

Little is known about the rates, timing, and causative microorganisms of deep surgical site infections after spinal arthrodesis in patients with genetic and syndromic scoliosis compared with patients with adolescent idiopathic scoliosis and kyphosis or patients with neuromuscular scoliosis.

METHODS

We reviewed data from 1,353 patients who were <21 years of age and had undergone spinal arthrodesis for deformity correction by 1 surgeon from 2000 to 2015. Deformity causes were genetic, idiopathic, or neuromuscular. We identified patients who had undergone an unplanned surgical procedure for a deep surgical site infection that was early (≤90 days after the procedure) or late (>90 days after the procedure). We compared deep surgical site infection rates, timing, and causative microorganisms by deformity cause.

RESULTS

Deep surgical site infections occurred in 65 patients (4.8%): 4.2% for patients with genetic and syndromic scoliosis, 2.7% for patients with adolescent idiopathic scoliosis and kyphosis, and 10.0% for patients with neuromuscular scoliosis. Of the deep surgical site infections, 26 (40%) occurred early and 39 (60%) occurred late. The median times to deep surgical site infection onset were 51 days (range, 7 days to 7 years) in patients with genetic and syndromic scoliosis, 827 days (range, 10 days to 12 years) in patients with adolescent idiopathic scoliosis and kyphosis, and 45 days (range, 13 days to 6 years) in patients with neuromuscular scoliosis. Seventy-six microorganisms (41 gram-positive and 35 gram-negative) were isolated from 47 children with positive cultures; the most common was coagulase-negative Staphylococcus (n = 13). The ratio of gram-positive to gram-negative microorganisms was highest in patients with adolescent idiopathic scoliosis and kyphosis (4:1) and lowest in patients with genetic and syndromic scoliosis (0.5:1). In genetic and syndromic scoliosis, both early and late deep surgical site infections were more frequently caused by gram-negative bacteria. In neuromuscular scoliosis, early deep surgical site infections were more frequently caused by gram-negative bacteria, and late deep surgical site infections were more frequently caused by gram-positive bacteria. In adolescent idiopathic scoliosis and kyphosis, both early and late deep surgical site infections were more commonly caused by gram-positive bacteria. Methicillin-resistant Staphylococcus aureus was identified in 2 late deep surgical site infections in patients with neuromuscular scoliosis.

CONCLUSIONS

Deep surgical site infections were more common in genetic and syndromic scoliosis than in adolescent idiopathic scoliosis and kyphosis, but less common than in neuromuscular scoliosis. Adolescent idiopathic scoliosis and kyphosis had the highest ratio of late to early deep surgical site infections. Patients with genetic and syndromic scoliosis had predominantly gram-negative microorganisms, particularly in early deep surgical site infections. Methicillin-resistant S. aureus infection was rare, occurring in only 2 patients with neuromuscular scoliosis. Gram-negative and gram-positive prophylactic antibiotics may be indicated for patients with genetic and syndromic scoliosis after spinal arthrodesis.

LEVEL OF EVIDENCE

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

Multiresonant High-Q Plasmonic Metasurfaces

Resonant metasurfaces are devices composed of nanostructured subwavelength scatterers that generate narrow optical resonances, enabling applications in filtering, nonlinear optics, and molecular fingerprinting. It is highly desirable for these applications to incorporate such devices with multiple high-quality-factor resonances; however, it can be challenging to obtain more than a pair of narrow resonances in a single plasmonic surface. Here, we demonstrate a multiresonant metasurface that operates by extending the functionality of surface lattice resonances, which are the collective responses of arrays of metallic nanoparticles. This device features a series of resonances with high-quality factors (Q ∼ 40), an order of magnitude larger than what is typically achievable with plasmonic nanoparticles, as well as a narrow free spectral range. This design methodology can be used to better tailor the transmission spectrum of resonant metasurfaces and represents an important step toward the miniaturization of optical devices.

Pediatric Gartland Type-IV Supracondylar Humeral Fractures Have Substantial Overlap with Flexion-Type Fractures

BACKGROUND

Knowledge is limited about the diagnosis and treatment of modified Gartland type-IV supracondylar humeral fractures. We determined the prevalence of type-IV fractures, identified preoperative characteristics associated with these injuries, and assessed operative treatment characteristics.

METHODS

We retrospectively identified patients <16 years of age who underwent operative treatment of a supracondylar humeral fracture at 2 centers between 2008 and 2016. We compared patient, injury, and treatment characteristics between type-IV and type-III fracture groups (1:4, cases:controls). Preoperative radiographs were assessed by 4 pediatric orthopaedists blinded to fracture type. The odds of a fracture being type IV were assessed using univariate logistic regression for individual radiographic parameters. Significance was set at alpha = 0.05.

RESULTS

Type-IV fractures accounted for 39 (1.3%) of the supracondylar humeral fractures treated operatively during the study period. A type-IV fracture was associated with the following radiographic parameters: flexion angulation (odds ratio [OR] = 17; 95% confidence interval [CI] = 4.9 to 59), valgus angulation (OR = 5.6; 95% CI = 1.6 to 20), and lateral translation (OR = 4.1; 95% CI = 1.6 to 11) of the distal fragment; osseous apposition between the proximal and distal fragments (OR = 4.0; 95% CI = 1.8 to 9.0); and propagation of the fracture line toward the diaphysis of the proximal segment (OR = 9.2; 95% CI = 1.6 to 53). We found no significant differences in patient or injury characteristics between the groups. Compared with type-III fractures, type-IV fractures were treated more frequently with open reduction and percutaneous pinning (13% compared with 3.8%; p = 0.04) and were associated with longer mean operative time (82 ± 42 compared with 63 ± 28 minutes; p = 0.001).

CONCLUSIONS

We identified 5 preoperative radiographic parameters associated with greater odds of a supracondylar humeral fracture being type IV rather than type III. No patient or injury characteristic differed significantly between the groups. Substantial overlap likely exists between type-IV and flexion-type fractures. Type-IV fractures were associated with longer operative time and were treated with open reduction more frequently than were type-III fractures.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

A Review of the Ecology and Management of Black Turpentine Beetle (Coleoptera: Curculionidae)

The black turpentine beetle, Dendroctonus terebrans Olivier is the largest pine-infesting bark beetle native to the southern and eastern United States. It generally reproduces in fresh stumps and bases of trees weakened or killed by other biotic or abiotic agents, although it can also infest and sometimes kills apparently healthy trees. Its numbers can build when large amounts of host material become available (typically through a disturbance), and black turpentine beetle-caused mortality at a local scale can become considerable. Here, we provide a complete review of the literature on this species, including its taxonomy, host, life history, chemical ecology, arthropod and microbial associates, and management options. We also provide original data on numbers of instars, acoustic signals, and pheromone chirality in this species. Our survey of the existing literature revealed that key biological characteristics of black turpentine beetles are known, but interactions with closely associated organisms, economic and ecological impacts, and improvements to monitoring and management practices have been only partially investigated.

Southern Pine Beetle (Coleoptera: Curculionidae: Scolytinae) Pheromone Component trans-Verbenol: Enantiomeric Specificity and Potential as a Lure Adjuvant

The southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) utilizes a multi-component aggregation pheromone to mediate mass-attacks and thereby colonize otherwise unsusceptible trees. Females produce the attractant frontalin and a synergist, trans-verbenol. We investigated trans-verbenol to determine whether enantiomeric composition, airborne concentration, and possibly other factors might affect its biological activity. Newly-emerged females from Mississippi populations produced 54-87% of the (-)-enantiomer; females initiating galleries in logs produced lower amounts and a wider range of enantiomeric ratios [12-92% (-)]. Coupled gas chromatography-electroantennographic detection (GC-EAD) studies did not suggest large differences in the concentration threshold of olfaction for the two enantiomers. We examined the effect of adding trans-verbenol to traps located outside infested areas and baited with components of the aggregation attractant. Male attraction was similarly increased by lures with 3, 81, or 98% of the (-)-enantiomer of trans-verbenol, whereas females preferred 81 over 3%. When release rate of 81% (-)-trans-verbenol in traps was varied across three orders of magnitude (0.3, 3, and 30 mg/d), the data suggested a positive dose-response trend. A high release (i.e., 2-5 g/d) device of host-odor alpha-pinene had a much stronger enhancing effect on trap catches than a trans-verbenol device (~30 mg/d), and trans-verbenol did not further enhance attraction when alpha-pinene was present. Our results suggest that the weak attraction-enhancing activity of trans-verbenol reported previously cannot be improved by adjusting the enantiomeric composition or release rate of lures, and furthermore there are no anticipated benefits of adding trans-verbenol to the D. frontalis monitoring lure.

Discrimination of Odors Associated With Conspecific and Heterospecific Frass by Sibling Species Dendroctonus frontalis (Coleoptera: Curculionidae: Scolytinae) and Dendroctonus mesoamericanus (Coleoptera: Curculionidae: Scolytinae)

In the Central American region, the aggressive, sibling bark beetles Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) and Dendroctonus mesoamericanus Armendáriz-Toledano & Sullivan (Coleoptera: Curculionidae: Scolytinae) commonly colonize pines concurrently, and in nature they avoid heterospecific pairing, although it can be produced in the lab. We performed walking arrestment bioassays in the lab to examine the capacity of both sexes of both species to discriminate odors from frass expelled from gallery entrances of either solitary females or conspecific pairs of either species. Males of both species strongly preferred odors of frass from solitary, conspecific females over those of heterospecific females or pairs of either species. Female D. frontalis did not discriminate among these frass categories, whereas female D. mesoamericanus preferred frass of conspecific females. In gas chromatography-electroantennographic detection and gas chromatography-mass spectrometry analyses, we determined that males of both species could sense a nearly identical spectrum of approximately 16 host- and beetle-produced compounds present in frass of females of one or both species. Only two of these compounds, endo-brevicomin and ipsdienol, which were present in frass of female D. mesoamericanus and pairs of either species but absent in frass of solitary D. frontalis females, qualitatively distinguished these categories. Several known attractants and synergists for either species declined in concentration postpairing. Our results complement earlier research and indicate how semiochemical composition and concentration in frass might mediate male discrimination of attack sites of conspecific, unpaired females. Furthermore, our data indicate that semiochemical responses for walking females differ from those of males and between species.

Routine bilateral neck exploration and four-gland dissection remains unnecessary in modern parathyroid surgery

Objective

Recent advances in preoperative imaging techniques and intraoperative parathyroid hormone (ioPTH) assays have made single-gland, minimally invasive parathyroidectomy (MIP) the preferred treatment option for most patients with primary hyperparathyroidism (pHPT). Despite this evolution, a recommendation for bilateral neck exploration (BNE) with four-gland dissection in all patients has recently been advocated by a parathyroid surgical group. The current study compares the long-term outcomes of MIP with those of conventional BNE with four-gland dissection in patients with pHPT.

Methods

In order to objectively assess a recommendation in the literature that universal BNE with four-gland dissection is advisable, all patients undergoing an initial MIP with ioPTH assessment for pHPT in a tertiary endocrine practice during a 10-year period were reviewed. The cure rates from this procedure were compared with published results of conventional BNE with four-gland dissection.

Results

Of the 561 patients undergoing parathyroidectomy during the study period, 337 had initial surgery for pHPT; 282 of these patients met inclusion criteria and 212 had sufficient follow-up data available. A single adenoma was identified in 87.3% of cases. Preoperative imaging studies were co-localizing in 148 (69.8%), and 127 (85.8%) of these patients with co-localizing imaging required only single-gland surgery. Imaging studies did not co-localize in 49 patients, yet 32 (65.3%) of these patients were still cured with unilateral surgery. The cure rate for patients undergoing MIP was 98.6%, with a long-term recurrence rate of <2%.

Conclusion

When coupled with the ioPTH assay, patients with at least one preoperative localizing study can undergo MIP and anticipate a cure rate of 99%, which is as good as or better than the published rates for conventional BNE with four-gland dissection. With unilateral surgery, the risks of permanent hypoparathyroidism and airway obstruction from bilateral vocal fold paralysis are completely eliminated. Therefore, despite recommendations to the contrary, most patients with pHPT should not have a planned four-gland exploration.

Level of Evidence

III or IV.

Surgically Relevant Patterns in Triplane Fractures: A Mapping Study

BACKGROUND

Triplane ankle fractures are complex transitional fractures that often necessitate surgical treatment. Axial fracture lines determine optimal screw trajectories for fixation. The purpose of our study was to identify fracture patterns in triplane fractures by illustrating fracture lines in the axial plane of the distal tibial metaphysis and epiphysis.

METHODS

We retrospectively reviewed records of children presenting with ankle fractures at 1 center from January 2007 through June 2017. Thirty-three cases of triplane fractures with available computed tomographic (CT) scans were identified. Fractures in the axial plane of the metaphysis were identified 10 mm proximal to the physis, and fractures in the epiphysis were identified midway between the physis and distal tibial articular surface. Fracture lines were drawn and were superimposed on unfractured bone templates to generate fracture maps, and heat maps were then created to show areas of high and low fracture densities.

RESULTS

In the metaphysis, the most common fracture pattern was medial-lateral lines in the posterior metaphysis. This metaphyseal pattern was consistent across 2, 3, 4, and 5-part fractures. There were clear zones of rare fracture involvement in the anterior and anterolateral metaphysis. In the epiphysis, anterior-to-posterior fracture lines were common in the anterior epiphysis. All cases had an epiphyseal fracture exit through the anterior epiphysis. Fracture extension into the posteromedial epiphysis was a feature of all fracture classes.

CONCLUSIONS

Fracture mapping of triplane fractures suggests consistent axial fracture patterns in the metaphysis and epiphysis with additional class-dependent fractures in the epiphysis. This study provides visual guidelines to assist surgeons in understanding the axial fracture patterns of individual triplane fractures for surgical planning.

Spatial Displacement of a Lure Component Can Reduce Catches of Two Nontarget Species During Spring Monitoring of Southern Pine Beetle

Local outbreak risk for the southern pine beetle, Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae), is forecast with a trapping survey conducted every spring throughout the southeastern United States. Traps baited with pine odors and components of the D. frontalis aggregation pheromone are used to obtain abundance estimates of both this species and its clerid predator Thanasimus dubius (F.) (Coleoptera: Cleridae); these data are entered into a predictive model that estimates outbreak risk. An attractant synergist for D. frontalis, endo-brevicomin, has recently been included in the survey lure, but it can have the unintended effect of attracting nontarget species Hylesinus pruinosus Eichhoff (Coleoptera: Curculionidae: Scolytinae) and Enoclerus nigripes (Say) (Coleoptera: Cleridae) which, due to their sometimes large numbers and general similarity in appearance to the target species, could complicate sorting and counting of trap catches. Analysis of bycatch data from a previously-published, 31-mo trapping study in Mississippi indicated that displacement of the endo-brevicomin releaser 6 m from the trap largely eliminated catches of the nontarget species H. pruinosus and E. nigripes while not reducing catches of the target species D. frontalis and T. dubius. Our analysis demonstrates that interspecific differences in spatial responses to attractive semiochemicals can be used to improve insect trap selectivity. Both nontarget beetle species were captured in highest numbers during late winter/early spring, coinciding with the D. frontalis survey.

Treatment of a Pediatric T-type Intercondylar Humerus Fracture With Hybrid Percutaneous Pinning and External Fixation

T-type intercondylar fractures of the distal humerus are rare injuries in skeletally immature patients. Few studies are available to guide the treatment of these injuries. Small case series and expert recommendations suggest superiority of the open approach for direct reduction of the articular surface. This approach poses risks of vascular compromise and elbow stiffness. However, success with percutaneous intercondylar screw fixation has been described for simple split patterns. The authors present a case that illustrates a novel percutaneous technique to treat this fracture type. A healthy 8-year-old boy sustained a T-type intercondylar fracture of the distal humerus (AO 13-C1). Excellent reduction was noted after closed reduction and crossed percutaneous pinning. Compression was applied across the pins through a small external fixator bar to address the intercondylar split component. At the 6-week postoperative clinic visit, the pins and fixator were removed uneventfully, and normal healing with full range of elbow motion was noted. This case report describes a simple, minimally invasive technique to treat uncomplicated T-type intercondylar fractures of the distal humerus in skeletally immature patients. Practitioners familiar with percutaneous fixation of supracondylar fractures can easily perform this technique. The described technique spares an open dissection and avoids permanent implants around the joint. Further multicenter research is warranted to determine the long-term outcomes and safety of the described technique. [Orthopedics. 2017; 40(6):e1096-e1098.].

Sacral-Alar-Iliac Fixation in Children with Neuromuscular Scoliosis: Minimum 5-Year Follow-Up

OBJECTIVE

To investigate the 5-year outcomes of children with neuromuscular scoliosis treated with sacral-alar-iliac screws.

METHODS

We reviewed clinical and radiographic records of patients aged ≤18 years treated by 1 pediatric orthopedic surgeon for neuromuscular scoliosis with spinal fusion using sacral-alar-iliac pelvic anchors. Thirty-eight patients with a minimum 5-year radiographic follow-up (mean, 6.0 ± 1.2 years) were studied. The mean patient age was 13 ± 2.0 years, and 47% were female. The mean number of levels fused was 18 ± 0.7. Two-thirds (66%) of the patients were diagnosed with cerebral palsy.

RESULTS

Between the preoperative period and final follow-up, the patients exhibited a mean correction of the major coronal curve of 79% (preoperative, 85° to final, 18°) and a mean 57% correction of the pelvic obliquity (preoperative, 16° to final, 7°). Patients maintained the correction of mean pelvic obliquity from the early postoperative period (6°) to final follow-up (7°). Preoperatively, 76% of the patients had a pelvic obliquity of >10°, compared with 26% of patients postoperatively. There were no cases of neurologic or vascular complications or pseudarthrosis. Radiographs revealed bilateral sacral-alar-iliac screw lucency in 8 patients; 4 of these patients had deep wound infections, and the other 4 were asymptomatic. Unilateral screw fracture was found in 1 patient with an 8-mm-diameter screw (1.3%; 1 of 76 screws); the patient was observed and remained asymptomatic. There were no cases of set screw displacement, screw back-out, or rod dislodgement.

CONCLUSIONS

Sacral-alar-iliac screws are safe and effective pelvic anchors for use in children with neuromuscular scoliosis.

Intra-Annual Variation in Responses by Flying Southern Pine Beetles (Coleoptera: Curculionidae: Scolytinae) to Pheromone Component endo-Brevicomin

The southern pine beetle Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) is attracted to an aggregation pheromone that includes the multifunctional pheromone component endo-brevicomin. The effect of endo-brevicomin on attractive lures varies from strong enhancement to reduction of beetle attraction depending upon release rate, lure component spacing, and proximity of beetle infestations. Anecdotal observations have further suggested that the effects of endo-brevicomin vary during the year. We investigated this possibility under nonoutbreak conditions in southwestern Mississippi where for two-and-a-half years we monitored traps baited with frontalin and the host odor alpha-pinene either (a) alone, or with an endo-brevicomin release device either (b) located directly on the trap, or (c) displaced 6 m away. The endo-brevicomin devices in our tests increased D. frontalis catches during all times of year, and 6 m displacement of the endo-brevicomin release device from the trap did not significantly alter responses except during the spring flight peak when displacement increased catches. Our data suggest that flying D. frontalis have a stronger tendency to avoid the immediate proximity of a release point of endo-brevicomin during their springtime dispersal flight when catches are greatest. Catches of Thanasimus dubius (F.) (Coleoptera: Cleridae), a major predator of D. frontalis, were not altered by endo-brevicomin, and ratios of D. frontalis to T. dubius changed over the course of the year. We discuss the possible effects of intra-annual variation in D. frontalis response to endo-brevicomin both on beetle attack behavior and use of endo-brevicomin as a lure adjuvant in D. frontalis population monitoring.

The Role of Multimodal Signals in Species Recognition Between Tree-Killing Bark Beetles in a Narrow Sympatric Zone

When related species coexist, selection pressure should favor evolution of species recognition mechanisms to prevent interspecific pairing and wasteful reproductive encounters. We investigated the potential role of pheromone and acoustic signals in species recognition between two species of tree-killing bark beetles, the southern pine beetle, Dendroctonus frontalis Zimmermann, and the western pine beetle, Dendroctonus brevicomis LeConte, in a narrow zone of sympatry, using reciprocal pairing experiments. Given the choice of adjacent con- or heterospecific female gallery entrance in a log, at least 85% of walking males chose the entrance of the conspecific, and half the males that initially entered heterospecific galleries re-emerged and entered the conspecific gallery within 15 min. Waveform analysis of female acoustic "chirps" indicated interspecific differences in chirp timing. Males may use information from female acoustic signals to decide whether to enter or remain in the gallery. Individuals in forced heterospecific pairings (produced by confinement of a heterospecific male within the female entrance) did not differ in pheromone production from individuals of conspecific pairs. However, due to the absence of the right species of male, galleries with heterospecific pairs released an abnormal pheromone blend that lacked at least one key component of the aggregation pheromone of either species. The complete aggregation pheromone (i.e., the pheromone blend from entrances with pairs) does not appear to deter interspecific encounters or confer premating reproductive isolation per se; however, it may confer selective pressure for the maintenance of other reproductive isolation mechanisms.

Western Pine Beetle Populations in Arizona and California Differ in the Composition of Their Aggregation Pheromones

We compared pheromone production and response for populations of western pine beetle, Dendroctonus brevicomis LeConte, from sites in northern Arizona and northern California. Volatiles were collected from individuals of both sexes that had mined as a pair in a Pinus ponderosa log for 1 d, and they were subsequently analyzed by gas chromatography coupled to mass-spectrometry. Principal component analysis of quantities of Dendroctonus pheromone components indicated strong site-associated clustering of blend composition for females but not males. Much of the clustering in females evidently was due to differences in the production of endo- and exo-brevicomin, which occurred in average ratios of 0.1:1 and 19:1 for populations in the California and Arizona sites, respectively. In the California site, exo- was better than endo-brevicomin in enhancing trap catches of both sexes to lures containing the host-tree odor α-pinene and the male-produced aggregation pheromone component frontalin. In an identical test in the Arizona site, endo- was a better adjuvant than exo-brevicomin for male attraction, whereas females did not show a significant preference. At neither location were the isomers antagonistic to one another in activity. Thus, one aggregation pheromone has apparently diverged between these populations, concurrent with published evidence that D. brevicomis on either side of the Great Basin are genetically distinct and are possibly different species. Furthermore, production of and response to the isomers of brevicomin by flying Dendroctonus frontalis Zimmermann in the Arizona site were similar to those of sympatric D. brevicomis. This interspecific signal overlap is likely sustainable since joint species mass-attacks may assist both species in overcoming host defenses, thereby increasing host availability.

Responses by Dendroctonus frontalis and Dendroctonus mesoamericanus (Coleoptera: Curculionidae) to Semiochemical Lures in Chiapas, Mexico: Possible Roles of Pheromones During Joint Host Attacks

In southern Mexico and Central America, the southern pine beetle Dendroctonus frontalis Zimmermann (Coleoptera: Curculionidae: Scolytinae) commonly colonizes host trees simultaneously with Dendroctonus mesoamericanus Armendáriz-Toledano and Sullivan, a recently described sibling species. We hypothesized that cross-species pheromone responses by host-seeking beetles might mediate joint mass attack, bole partitioning, and reproductive isolation between the species. Previous studies had indicated that D. frontalis females produce frontalin and that female D. mesoamericanus produce frontalin, endo-brevicomin, and ipsdienol (males of both species produce endo-brevicomin and possibly ipsdienol). In field trapping trials in the Mexican state of Chiapas, D. frontalis was attracted to the lure combination of turpentine and racemic frontalin; racemic endo-brevicomin enhanced this response. In a single test, D. mesoamericanus was attracted in low numbers to the combination of turpentine, racemic frontalin, and racemic endo-brevicomin after the addition of racemic ipsdienol; in contrast, racemic ipsdienol reduced responses of D. frontalis. Inhibition of D. frontalis was generated in both sexes by (+)- and racemic ipsdienol, but by (−)-ipsdienol only in females. Logs infested with D. mesoamericanus females (the pioneer sex in Dendroctonus) attracted both species in greater numbers than either D. frontalis female-infested or uninfested logs. Our data imply that D. frontalis may be more attracted to pioneer attacks of D. mesoamericanus females, and that this could be owing to the presence of endo-brevicomin in the latter. Possible intra- and inter-specific functions of semiochemicals investigated in our experiments are discussed.

Sex Pheromone of the Baldcypress Leafroller (Lepidoptera: Tortricidae)

The baldcypress leafroller, Archips goyerana Kruse (Lepidoptera: Tortricidae), is a specialist on Taxodium distichum (L.) Richard and has caused serious defoliation in swamps of southeastern Louisiana, accelerating decline of baldcypress forests concurrently suffering from nutrient depletion, prolonged flooding, and saltwater intrusion. We investigated the composition of the sex pheromone of this species. Coupled gas chromatography-electroantennographic detection (GC-EAD) analyses indicated that male antennae were sensitive to four compounds [(Z)-11-tetradecenyl acetate (Z11-14:OAc), (E)-11-tetradecenyl acetate (E11-14:OAc), (Z)-9-tetradecenyl acetate (Z9-14:OAc), and (Z)-11-tetradecen-1-ol (Z11-14:OH)] present in female abdominal tip extracts in an approximately 100:1.5:0.6:10 ratio. In trapping trials performed in a cypress-tupelo swamp in southeastern Louisiana, moths were attracted to blends of these four components presented in approximately the female-produced ratios. Elimination of Z11-14:OH had no impact on moth response, whereas elimination of any of the three acetates strongly reduced or eliminated attraction. A blend in which the E11:Z11 ratio of 14:OAc was 5:100 was much less attractive than the same blend with the female produced ratio of 1.5:100. A. goyerana is closely related to the sympatric species Archips argyrospilus (Walker) with which it was previously synonymous. Our data revealed differences between the pheromone composition of A. goyerana and that reported for A. argyrospilus, which could account for the apparent absence of cross-attraction between these species. We conclude that a lure containing a 100:1.5:0.6 ratio of Z11-14:OAc, E11-14:OAc, and Z9-14:OAc has the potential to be used in traps to detect and measure A. goyerana populations and thereby monitor an important biotic factor contributing to the loss of coastal baldcypress forests.

J. A. Dobrowolski (1931-2013): in memoriam

J. A. Dobrowolski, or George, as he was known to his friends and colleagues, passed away on February 12, 2013 in Ottawa, Ontario. George was a leading pioneer in the field of optical thin films. His work stretched over 60 years beginning with his graduate studies in 1953, and he impacted all areas of research in this field. This in memoriam outlines both his professional career and personal life; as befitting George, there is a comprehensive list of his numerous publications in books, papers, and patents. An in memoriam talk on George's life and career was presented at the 2013 Optical Interference Coatings Conference held in Whistler, B.C., Canada on June 16-21, 2013.

Variation in manuka oil lure efficacy for capturing Xyleborus glabratus (Coleoptera: Curculionidae: Scolytinae), and cubeb oil as an alternative attractant

Redbay ambrosia beetle, Xyleborus glabratus Eichoff, is an exotic species to North America vectoring a deadly vascular wilt disease of redbay [Persea borbonia (L.) Spreng], swampbay [P. palustris (Raf.) Sarg.], avocado (P. americana Mill.), and sassafras [Sassafras albidum (Nutt.) Nees]. Xyleborus glabratus is attracted to manuka oil lures, which are commercially available, and phoebe oil. Variable efficacy of manuka oil lures and insufficient availability of phoebe oil prompted us to investigate the reasons behind changes in manuka oil lure efficacy and to test cubeb oil, a readily available essential oil from Piper cubeba L. seeds, as an alternative attractant. Attraction, release rates and durations, and volatile composition of manuka oil lures manufactured in 2008 were compared with manuka oil lures manufactured in 2012, and to whole and a distilled fraction of cubeb oil. Manuka oil lures from 2008 were more attractive to X. glabratus than controls for 8 wk, whereas lures from 2012 were attractive for only 2 wk. Cubeb oil and the distilled fraction of it were as attractive as or more attractive than manuka oil in three trials. In gravimetric studies, manuka oil lures from 2008 and cubeb oil lures continued to release volatiles for 57 d, whereas lures from 2012 stopped after 16 d. The chemical composition of volatiles released from new manuka oil lures from 2008 was similar to 2012; however, a preservative (butylated hydroxytoluene) was detected in the 2008 lures. Cubeb oil was an effective attractant for X. glabratus that lasted 8-9 wk when released from bubble lures.

The role of uncertainty and reward on eye movements in a virtual driving task

Eye movements during natural tasks are well coordinated with ongoing task demands and many variables could influence gaze strategies. Sprague and Ballard (2003) proposed a gaze-scheduling model that uses a utility-weighted uncertainty metric to prioritize fixations on task-relevant objects and predicted that human gaze should be influenced by both reward structure and task-relevant uncertainties. To test this conjecture, we tracked the eye movements of participants in a simulated driving task where uncertainty and implicit reward (via task priority) were varied. Participants were instructed to simultaneously perform a Follow Task where they followed a lead car at a specific distance and a Speed Task where they drove at an exact speed. We varied implicit reward by instructing the participants to emphasize one task over the other and varied uncertainty in the Speed Task with the presence or absence of uniform noise added to the car's velocity. Subjects' gaze data were classified for the image content near fixation and segmented into looks. Gaze measures, including look proportion, duration and interlook interval, showed that drivers more closely monitor the speedometer if it had a high level of uncertainty, but only if it was also associated with high task priority or implicit reward. The interaction observed appears to be an example of a simple mechanism whereby the reduction of visual uncertainty is gated by behavioral relevance. This lends qualitative support for the primary variables controlling gaze allocation proposed in the Sprague and Ballard model.

Electrophysiological and behavioral responses of the bark beetle Dendroctonus rhizophagus to volatiles from host pines and conspecifics

The bark beetle Dendroctonus rhizophagus is endemic to northwestern Mexico where it kills immature pines < 3 m tall. We report the first investigation of the chemical ecology of this pest of forest regeneration. We used GC-EAD to assess olfactory sensitivity of this species to volatile compounds from: resin of a major host, Pinus arizonica; mid/hindguts of single, gallery-initiating females; and mate-paired males within galleries of attacked host trees in the field. Antennae of both sexes responded to monoterpenes α-pinene, β-pinene and 3-carene as well as to the beetle-derived oxygenated monoterpenes fenchyl alcohol, myrtenal, cis-verbenol, trans-verbenol, verbenone, and myrtenol. These monoterpenes were quantified from pre-emerged D. rhizophagus adults forced to attack host tissue in the laboratory, and from individuals dissected from naturally-attacked hosts at different stages of colonization. In both bioassays, myrtenol and trans-verbenol were the most abundant volatiles, and trans-verbenol was the only one produced in significantly greater quantities by females than males in a naturally-colonized host. Two field experiments were performed to evaluate behavioral responses of D. rhizophagus to antennally-active monoterpenes. Results show that 3-carene was significantly attractive either alone or in a ternary (1:1:1) combination with α-pinene and β-pinene, whereas neither α-pinene nor β-pinene alone were attractive. None of the beetle-associated oxygenated monoterpenes enhanced the attractiveness of the ternary mixture of monoterpenes, while verbenone either alone or combined with the other five oxygenated terpenes reduced D. rhizophagus attraction to the ternary mixture. The results suggest that attraction of D. rhizophagus to the host tree P. arizonica is mediated especially by 3-carene. There was no conclusive evidence for an aggregation or sex attractant pheromone.

Abstract LB-194: The Wnt inhibitor VS-507 reduces cancer stem cell (CSC) function in vitro and tumorigenicity in mice

VS-507 was previously identified as a selective inhibitor of cancer stem cells (Gupta et al., Cell, 2009) using a high throughput screen that capitalized on the cancer stem cell (CSC) phenotype of cells pushed through EMT (epithelial-mesenchymal transition). We have now characterized the mechanism, CSC selectivity and anti-tumor activity of VS-507. In Wnt3A-stimulated MDA-MB-231 breast cancer cells, VS-507 was found to preferentially inhibit β-catenin signaling in a dose-dependent manner as indicated by a TOP-Flash reporter assay. Inhibition of β-catenin signaling in VS-507-treated cells correlated with decreased protein expression of LRP6, the common co-receptor of the Wnt signaling pathway. Since human mammary cells driven through EMT by stable overexpression of the transcription factor Twist have been shown to demonstrate the hallmarks of CSCs, we used HMLE-Twist cells to assess selectivity of VS-507 for CSC inhibition. In proliferation assays, VS-507 showed 10-fold greater potency against CSC-like mesenchymal HMLE-Twist cells as compared to non-CSC-like epithelial control HMLE cells. In addition, VS-507 induced dose-dependent inhibition of tumorsphere formation by MDA-MB-231 cells, further indicating inhibition of the CSC phenotype. The preferential effects of VS-507 on mesenchymal breast cancer cell lines relative to epithelial breast cancer cell lines was further probed among a panel of 13 adherent human breast cancer cell lines. In general, triple negative mesenchymal breast cancer cell lines such as MDA-MB-436 or HCC1395 were more potently inhibited by VS-507 than were epithelial breast cancer cell lines such as MCF7 or HCC1937. Finally, efficacy of VS-507 was characterized upon systemic administration of the compound to mice. Inhibition of both primary tumor growth and experimental metastasis were observed in triple negative breast cancer models. These observations suggest that VS-507 is a potent anti-tumor agent that attenuates Wnt/β-catenin signaling, cancer stem cell self-renewal, tumor growth and metastasis. These results support clinical development of VS-507 for the treatment of triple negative breast cancer.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr LB-194. doi:1538-7445.AM2012-LB-194

Semiochemical emission from individual galleries of the southern pine beetle, (Coleoptera: Curculionidae: Scolytinae), attacking standing trees

We collected, identified, and quantified volatiles arising from individual gallery entrances of the monogamous bark beetle Dendroctonus frontalis Zimmermann. Samples were collected while the insects were mass attacking mature loblolly pines (Pinus taeda L.) in an established infestation in western Mississippi, 1 August through 3 October 2005. Following volatile sample collection, the entrances were dissected and categorized according to those that 1) contained a solitary female (the gallery initiating sex), 2) contained a pair that had not yet produced an egg gallery, 3) led to an egg gallery with niches and/or eggs, or 4) represented failed attacks (either abandoned or containing dead beetles). The greatest mean release rate of the female-produced aggregation pheromone components frontalin (74 ng/h) and trans-verbenol (0.35 microg/h) was detected from entrances of solitary females, whereas the highest mean quantities of the male-produced multifunctional pheromone components endo-brevicomin (18 ng/h) and verbenone (0.15 microg/h) were detected from entrances of preoviposition beetle pairs. Alpha-pinene, a host-produced monoterpene that functions as a synergist for the aggregation attractant for D. frontalis, was detected from entrances of solitary females and preoviposition pairs at a rate of 0.6 mg/h, or 3-4 orders of magnitude greater than the insect-produced components of the attractant. Our results indicate that the release rates of pheromone components used in published field studies of the chemical ecology of D. frontalis (generally > 0.1 mg/h) represent thousands of 'attack equivalents' or production rates on the scale of a beetle mass attack on a single host. Additionally, our data suggest that the loss in attractiveness of host tissue fully colonized by D. frontalis is because of the disappearance of attractants rather than an increase in inhibitors.

Cytokeratin 18 expression inhibits cytokine-induced death of cervical cancer cells

OBJECTIVES

In cervical cancer, increased cytokeratin 18 (CK18) filament expression is associated with disease progression. However, it may also provide resistance to cytokine-induced apoptosis. The present study tested whether CK18 expression influences susceptibility to cytokine-induced apoptosis.

METHODS

The cervical cancer cell lines C-4II (high CK18 expression), ME-180 (low CK18 expression), and 2 subtypes of HeLa cells containing or lacking CK18 expression (CK18+ and CK18- cells, respectively) were exposed to vehicle (control), Fas ligand (FasL) (50 ng/mL), or tumor necrosis factor α (TNF-α; 10 ng/mL) without/with cycloheximide (CHX; 2.5 μg/mL) to test the hypothesis that diminished CK18 expression increases susceptibility to cytokine-induced apoptosis.

RESULTS

Flow cytometric analysis of cell death via TUNEL staining revealed that cytokine-induced apoptosis was 2-fold greater in ME-180 cells than C-4II cells in response to FasL+CHX or TNF-α+CHX (P < 0.05). Similarly, there was a higher incidence of FasL-induced apoptosis in CK18- HeLa cells (23% and 91% apoptotic for FasL and FasL+CHX, respectively) than CK18+ HeLa cells (1% and 11%, respectively; P < 0.05). Surprisingly, TNF-α had no effect on either CK18+ or CK18- HeLa cells (P > 0.05). Caspase 3 activity was greater in CK18- HeLa cells than in CK18+ HeLa cells at 8 and 18 hours after FasL treatment (P < 0.05), an effect abrogated by the caspase 8 inhibitor IETD-fmk (P < 0.05).

CONCLUSIONS

Cervical cancer cells with diminished CK18 expression are more susceptible to cytokine-induced apoptosis, particularly in response to FasL treatment. These observations suggest that relative CK18 expression is an important factor when considering therapeutic strategies to enhance immune cell-mediated death of cervical cancer cells.

Expression and distribution of cytokeratin 8/18 intermediate filaments in bovine antral follicles and corpus luteum: an intrinsic mechanism of resistance to apoptosis?

Apoptosis is a mechanism of cell elimination during follicular atresia and luteal regression. Recent evidence suggests sensitivity to apoptosis in some cell types is partly dependent upon cytokeratin-containing intermediate filaments. Specifically, cytokeratin 8/18 (CK8/18) filaments are thought to impart resistance to apoptosis. Here, cytokeratin filament expression within bovine ovarian follicles and corpora lutea (CL) was characterized and the potential relationship between cell-specific CK8/18 expression and apoptosis explored. Immunoprecipitation and western blot analysis confirmed CK8 associates with CK18 to form CK8/18 heterodimeric filaments within bovine ovarian cells. Immunostaining revealed populations of CK18-positive (CK18+) cells in healthy growing follicles that increased in postovulatory follicles. Atretic follicles at all stages of atresia also contained some CK18+ cells. However, no CK18+ cells were detected in primordial or primary follicles. In CL, developing CL contained a higher proportion of CK18+ cells (approximately 35%, range 30-70%) than mature CL (approximately 16%) and regressing CL (approximately 5%; P<0.05, n = 3-5 CL/stage), suggesting CK8/18 filament expression diminishes over time, as luteal cells become more susceptible to apoptosis. Dual-fluorescence labeling for CK18 and a cell death marker (TUNEL labeling) confirmed this view, demonstrating less death of CK18+ than CK18- luteal cells throughout the estrous cycle (P<0.05). The results indicate differential expression of CK8/18 filaments occurs in cells of bovine ovarian follicles and CL throughout the estrous cycle. The prevalence and cell-specific pattern of cytokeratin expression in these structures is consistent with the concept these filaments might impart resistance to apoptosis in ovarian cells as is seen in other cell types.

Characterization of an aggregation pheromone in Hylesinus pruinosus (Coleoptera: Curculionidae: Scolytinae)

We conducted laboratory and field bioassays to characterize the pheromone system of an ash bark beetle, Hylesinus pruinosus Eichhoff (Coleoptera: Curculionidae: Scolytinae). Solitary females in newly initiated galleries in ash logs produced (+)-exo-brevicomin, whereas male beetles paired with females produced (+)-endo-brevicomin, lesser quantities of (+)-exo-brevicomin, and a third compound that could not be identified. Beetles produced these compounds also after exposure to juvenile hormone III, and they were the sole volatile chemicals isolated from beetles or aerations of infested logs that elicited electrophysiological responses from antennae of either sex. In the field, both sexes were strongly attracted to traps baited solely with either racemic or pure (+)-endo-brevicomin. Racemic exo-brevicomin was much less attractive to both sexes than racemic endo-brevicomin, and it did not increase attraction of endo-brevicomin when released in combination. Host odors (volatiles from mechanically damaged ash branches) failed to attract beetles or increase attractiveness of racemic exo-brevicomin. Our evidence suggests that male-produced (+)-endo-brevicomin is the major component of an aggregation pheromone for H. pruinosus, with (+)-exo-brevicomin and the unidentified male compound playing an indeterminate role in the chemical ecology of this species. Our data thus show an instance in which the major aggregation pheromone component of a bark beetle is produced by the secondarily arriving sex, a rare occurrence in bark beetles but one which has been reported previously for the Hylesini.

Field response of Dendroctonus frontalis (Coleoptera: Scolytinae) to synthetic semiochemicals in Chiapas, Mexico

Dendroctonus frontalis Zimmermann (Coleoptera: Scolytinae) is the most serious pest of pines (Pinus spp.) in Mexico. Conspecifics are attracted to trees undergoing colonization by the aggregation pheromone frontalin, which is synergized by odors of pine oleoresin released from beetle-damaged host tissue. Synthetic racemic frontalin combined with turpentine has been the operational bait used in traps for monitoring populations of D. frontalis in Mexico as well as the United States. Recently, racemic endo-brevicomin has been reported to be a synergist of the frontalin/turpentine bait and as an important component of the aggregation pheromone for D. frontalis populations in the United States. To determine whether racemic endo-brevicomin also might function as an aggregation synergist for the geographically isolated D. frontalis populations of Central America and Mexico, we performed a field trapping trial in Lagunas de Montebello National Park, Chiapas, Mexico, during July and August 2007. The combination of endo-brevicomin (placed either directly on the trap or 4 m away) plus racemic frontalin and turpentine caught at least 5 times more D. frontalis of both sexes than did turpentine either alone or in combination with either frontalin or endo-brevicomin. The addition of endo-brevicomin to the frontalin/turpentine bait also increased the proportion of females trapped. We conclude that the addition of endo-brevicomin might substantially improve the efficiency of the frontalin/turpentine bait for monitoring of D. frontalis in Central America and Mexico. We discuss factors that reconcile our results with previous studies that reported endo-brevicomin to be an attractant antagonist for populations of D. frontalis in Mexico and Honduras.

Ablation of leptin signaling disrupts the establishment, development, and maintenance of endometriosis-like lesions in a murine model

Leptin, a 16-kDa cytokine, has been implicated in several reproductive processes and disorders. Notably, elevated leptin levels in the peritoneal fluid of women with mild endometriosis has been demonstrated, suggesting a role for this cytokine in the early stages of disease establishment. To gain insight into the functional significance of leptin during the initial requisite proliferative and neovascularization events involved in endometriosis, we investigated the effect of disruption of in vivo leptin signaling on the establishment and/or maintenance of an endometriosis-like lesion in a syngeneic immunocompetent mouse model of endometriosis. Findings of this study show that the disruption of leptin signaling by ip injection of the pegylated leptin peptide receptor antagonist (LPrA) impairs the establishment of endometriosis-like lesions (derived from uteri of C57BL/6 female siblings) and results in a reduction of viable organized glandular epithelium, vascular endothelial growth factor-A expression, and mitotic activity. LPrA treatment resulted in a significant reduction of microvascular density in endometriosis-like lesions after continuous and acute courses. Endometriosis-like lesions (derived from tissue with functional leptin receptor) of Lepr(db) hosts (nonfunctional leptin receptor) were phenotypically similar to those of LPrA-treated mice. Our results confirm that leptin signaling is a necessary component in lesion proliferation, early vascular recruitment, and maintenance of neoangiogenesis in a murine model of endometriosis.

Attraction of the southern pine beetle, Dendroctonus frontalis, to pheromone components of the western pine beetle, Dendroctonus brevicomis (Coleoptera: Curculionidae: Scolytinae), in an allopatric zone

Subtle differences in pheromone components of sympatric species should be attractive only to the producing species and unattractive or repellent to the nonproducing species, and thereby maintain reproductive isolation and reduce competition between species. Bark beetles Dendroctonus brevicomis and D. frontalis (Coleoptera: Curculionidae) are known to have common pheromone components, except for exo-brevicomin, which is produced by D. brevicomis. We predicted that D. frontalis would not respond to exo-brevicomin outside of the zone of sympatry with D. brevicomis. We conducted a field experiment to determine the effect of exo-brevicomin on attraction of D. frontalis and associated species in Mississippi. We determined whether D. frontalis pheromone production differed inside and outside the sympatric zone and compared the pheromone profiles with D. brevicomis within the sympatric zone. Trapping studies revealed that D. frontalis can perceive and respond positively to exo-brevicomin, an aggregation pheromone of a sympatric congener (D. brevicomis), at locations hundreds of kilometers outside the sympatric zone. Qualitative pheromone profiles showed that both species emit similar pheromone components: frontalin, endo-brevicomin, exo-brevicomin, trans-verbenol, verbenone, and myrtenol. Although not previously reported, D. frontalis males from Arizona produced exo-brevicomin. The predator Thanasimus dubius did not discriminate traps baited with exo-brevicomin and was most attracted to traps with frontalin. Hylastes beetles were significantly attracted to traps baited with exo-brevicomin in combination with other compounds. Our results raise new practical and evolutionary questions on the role of exo-brevicomin in the behavioral ecology of D. frontalis. The addition of exo-brevicomin to the current lure might increase the efficiency of trapping programs in the southeastern United States.

An automated approach to detecting signals in electroantennogram data

Coupled gas chromatography/electroantennographic detection (GC-EAD) is a widely used method for identifying insect olfactory stimulants present in mixtures of volatiles, and it can greatly accelerate the identification of insect semiochemicals. In GC-EAD, voltage changes across an insect's antenna are measured while the antenna is exposed to compounds eluting from a gas chromatograph. The antenna thus serves as a selective GC detector whose output can be compared to that of a "general" GC detector, commonly a flame ionization detector. Appropriate interpretation of GC-EAD results requires that olfaction-related voltage changes in the antenna be distinguishable from background noise that arises inevitably from antennal preparations and the GC-EAD-associated hardware. In this paper, we describe and compare mathematical algorithms for discriminating olfaction-generated signals in an EAD trace from background noise. The algorithms amplify signals by recognizing their characteristic shape and wavelength while suppressing unstructured noise. We have found these algorithms to be both powerful and highly discriminatory even when applied to noisy traces where the signals would be difficult to discriminate by eye. This new methodology removes operator bias as a factor in signal identification, can improve realized sensitivity of the EAD system, and reduces the number of runs required to confirm the identity of an olfactory stimulant.

High individual variation in pheromone production by tree-killing bark beetles (Coleoptera: Curculionidae: Scolytinae)

Aggregation via pheromone signalling is essential for tree-killing bark beetles to overcome tree defenses and reproduce within hosts. Pheromone production is a trait that is linked to fitness, so high individual variation is paradoxical. One explanation is that the technique of measuring static pheromone pools overestimates true variation among individuals. An alternative hypothesis is that aggregation behaviour dilutes the contribution of individuals to the trait under selection and reduces the efficacy of natural selection on pheromone production by individuals. We compared pheromone measurements from traditional hindgut extractions of female southern pine beetles with those obtained by aerating individuals till they died. Aerations showed greater total pheromone production than hindgut extractions, but coefficients of variation (CV) remained high (60-182%) regardless of collection technique. This leaves the puzzle of high variation unresolved. A novel but simple explanation emerges from considering bark beetle aggregation behaviour. The phenotype visible to natural selection is the collective pheromone plume from hundreds of colonisers. The influence of a single beetle on this plume is enhanced by high variation among individuals but constrained by large group sizes. We estimated the average contribution of an individual to the pheromone plume across a range of aggregation sizes and showed that large aggregation sizes typical in mass attacks limit the potential of natural selection because each individual has so little effect on the overall plume. Genetic variation in pheromone production could accumulate via mutation and recombination, despite strong effects of the pheromone plume on the fitness of individuals within the aggregation. Thus, aggregation behaviour, by limiting the efficacy of natural selection, can allow the persistence of extreme phenotypes in nature.

Evidence that (+)-endo-brevicomin is a male-produced component of the Southern pine beetle aggregation pheromone

Previous research indicated that the aggregation pheromone of the southern pine beetle, Dendroctonus frontalis, is produced only by females, the sex that initiates attacks. We provide evidence indicating that secondarily arriving males augment mass aggregation by releasing the attractive synergist (+)-endo-brevicomin. Healthy pines artificially infested with both sexes of D. frontalis were significantly more attractive to conspecifics than trees infested solely with females. Coupled gas chromatography-electroantennographic detection (GC-EAD) analyses of volatiles isolated from male beetles revealed substantially greater olfactory sensitivity by D. frontalis to endo-brevicomin than to any other component. The threshold of detection of both sexes for (+)-endo-brevicomin was four orders of magnitude lower than for its antipode and at least one order of magnitude lower than for either enantiomer of frontalin, the major female-produced aggregation pheromone component. Pairing with a female in a gallery stimulated individual male beetles to produce hundreds of nanograms of (+)-endo-brevicomin. (+)-endo-Brevicomin was detected in a small percentage of female D. frontalis, whereas (-)-endo-brevicomin was never detected in either sex. In field trapping bioassays, we confirmed that (+)-endo-brevicomin is a potent synergist for attractive combinations of frontalin and pine turpentine. However, (+)-endo-brevicomin failed to attract D. frontalis either when presented alone or in combination with turpentine. We postulate that mass colonization of host trees by D. frontalis is mediated by distinct semiochemicals from both sexes rather than females alone. Our discovery of a key aggregation pheromone component in such an apparently well-studied species implies that the pheromone models of other bark beetles could benefit from systematic reexamination using newer technologies. Additionally, baits fortified with (+)-endo-brevicomin may enhance pest management strategies that exploit attractants for D. frontalis.

Leptin Signaling Promotes the Growth of Mammary Tumors and Increases the Expression of Vascular Endothelial Growth Factor (VEGF) and Its Receptor Type Two (VEGF-R2)

To gain insight into the mechanism(s) by which leptin contributes to mammary tumor (MT) development we investigated the effects of leptin, kinase inhibitors, and/or leptin receptor antagonists (LPrA2) on 4T1 mouse mammary cancer cells in vitro and LPrA2 on 4T1-MT development in vivo. Leptin increases the expression of vascular endothelial growth factor (VEGF), its receptor (VEGF-R2), and cyclin D1 through phosphoinositide 3-kinase, Janus kinase 2/signal transducer and activator of transcription 3, and/or extracellular signal-activated kinase 1/2 signaling pathways. In contrast to leptin-induced levels of cyclin D1 the changes in VEGF or VEGF-R2 were more dependent on specific signaling pathways. Incubation of 4T1 cells with anti-VEGF-R2 antibody increased leptin-mediated VEGF expression suggesting an autocrine/paracrine loop. Pretreatment of syngeneic mice with LPrA2 prior to inoculation with 4T1 cells delayed the development and slowed the growth of MT (up to 90%) compared with controls. Serum VEGF levels and VEGF/VEGF-R2 expression in MT were significantly lower in mice treated with LPrA2. Interestingly, LPrA2-induced effects were more pronounced in vivo than in vitro suggesting paracrine actions in stromal, endothelial, and/or inflammatory cells that may impact the growth of MT. Although all the mechanism(s) by which leptin contributes to tumor development are unknown, it appears leptin stimulates an increase in cell numbers, and the expression of VEGF/VEGF-R2. Together, these results provide further evidence suggesting leptin is a MT growth-promoting factor. The inhibition of leptin signaling could serve as a potential adjuvant therapy for treatment of breast cancer and/or provide a new target for the designing strategies to prevent MT development.

Fitness consequences of pheromone production and host selection strategies in a tree-killing bark beetle (Coleoptera: Curculionidae: Scolytinae)

Timing of arrival at a resource often determines an individual's reproductive success. Tree-killing bark beetles can reproduce in healthy trees by attacking in adequate numbers to overcome host defences that could otherwise be lethal. This process is mediated by aggregation and antiaggregation pheromones. Beetles that arrive early in such a "mass attack" must contend with undiminished tree defences, and produce enough pheromones to attract more beetles, but have a head start on gallery construction and egg-laying. Beetles that arrive late may be impeded by competition and diminishing availability of phloem, but should experience fewer costs associated with pheromone production and battling tree defences. We investigated relationships between timing of arrival, body size, pheromone production and fitness in the southern pine beetle, Dendroctonus frontalis. In field experiments, we captured beetles that arrived early (pioneers) and late on slash pine trees, Pinus elliottii, and measured pheromone amounts in their hindguts. We marked gallery entrances of beetles as they landed on a tree and measured their reproductive success after the attack terminated. We found no difference in body size or pheromone amounts between early and late arrivers. Most beetles arrived at the middle of the attack sequence, and excavated longer galleries per day than early arrivers. The number of offspring produced per day by beetles that established galleries midway through mass attack was higher than those that arrived early or very late in the sequence. Our results suggest that beetles do not exhibit adaptive phenotypic plasticity in pre-landing pheromone production, depending on the extent of previous colonisation of a host. Rather, it appears that stabilising selection favours beetles that attack in the middle of the sequence, and contributes to attack synchrony. Synchronous attack on trees is essential before population booms characteristic of tree-killing bark beetles can occur in nature.

Electrophysiological and behavioral responses of Dendroctonus frontalis (Coleoptera: Curculionidae) to volatiles isolated from conspecifics

Olfactory sensitivity of the southern pine beetle, Dendroctonus frontalis Zimmermann, to compounds isolated from the mid/hindguts of newly emerged conspecific adults was assayed with coupled gas chromatography-electroantennographic detection. All previously reported pheromones for D. frontalis plus eight additional compounds (fenchyl alcohol, myrtenal, cis-verbenol, trans-pinocarveol, acetophenone, trans-myrtanol, cis-myrtanol, and 2-phenylethanol) consistently elicited antennal responses from at least one sex. The eight additional compounds were assayed individually at three release rates (0.4-0.8, 3-9, and 25-100 mg/d) for the ability to alter D. frontalis responses to traps baited with D. frontalis attractant (4 mg/d frontalin and 17 mg/d alpha-pinene). At the high release rate, cis-verbenol enhanced attraction of D. frontalis females, whereas the other seven compounds significantly reduced attraction of one or both sexes. Acetophenone significantly reduced attraction of male D. frontalis at the low release rate, and five compounds (fenchyl alcohol, trans-pinocarveol, acetophenone, cis-myrtanol, and 2-phenylethanol) reduced attraction of one or both sexes at the intermediate rate. Only acetophenone significantly altered the sex ratio of beetles trapped, decreasing the proportion of males. Attraction of predatory checkered beetles (Cleridae) was enhanced by cis-verbenol released at the high rate but was not altered by any compound inhibitory to D. frontalis. Analyses of volatiles from individual D. frontalis indicated that the majority of the eight compounds were produced in greater quantities by newly emerged beetles than ones attacking pine bolts. Five of the compounds were associated predominantly with one sex. Possible ecological roles of these compounds in the biology of D. frontalis are discussed.