Nasal Septal Perforation Secondary to Graft-Versus-Host Disease.

Nasal septal perforation is a full-thickness defect of the nasal septum. There are many described etiologies of nasal septal perforation, including trauma, infectious, neoplastic, iatrogenic, and autoimmune. Graft-versus-host disease (GVHD) is a common and potentially life-threatening complication that can occur after an allogenic transplant. GVHD can result in the development of autoantibodies that lead to granulomatous inflammation with necrotizing vasculitis, causing perforation of the nasal septum. In this report, we describe a patient with nasal septal perforation secondary to GVHD and hope to provide novel insights into the association of GVHD and nasal septal perforation.

Plasminogen Binding and Activation at the Mesothelial Cell Surface Promotes Invasion through a Collagen Matrix.

Plasminogen (Plg) activation to the serine protease plasmin (Pla) plays a key role in regulating wound healing and fibrotic responses, particularly when bound to cell surface receptors. Our previous work suggested that mesothelial cells bind Plg at the cell surface, though no Plg receptors were described for these cells. Since mesothelial cells contribute to injury responses, including cellular differentiation to a mesenchymal-like phenotype and extracellular matrix remodeling, we hypothesized that Plg binding would promote these responses. Here, we confirm that Plg binds to both pleural and peritoneal mesothelial cells via the lysine-binding domain present in Plg, and we demonstrate the presence of three Plg receptors on the mesothelial cell surface: α-Enolase, Annexin A2, and Plg-RKT. We further show that bound-Plg is activated to Pla on the cell surface and that activation is blocked by an inhibitor of urokinase plasminogen activator or by the presence of animal-derived FBS. Lastly, we demonstrate that Plg promotes mesothelial cell invasion through a type I collagen matrix but does not promote cellular differentiation or proliferation. These data demonstrate for the first time that mesothelial cells bind and activate Plg at the cell surface and that active Pla is involved in mesothelial cell invasion without cell differentiation.

Does urbanization favour exotic bee species? Implications for the conservation of native bees in cities.

A growing body of research indicates that cities can support diverse bee communities. However, urbanization may disproportionately benefit exotic bees, potentially to the detriment of native species. We examined the influence of urbanization on exotic and native bees using two datasets from Michigan, USA. We found that urbanization positively influenced exotic-but not native-bee abundance and richness, and that this association could not be explained by proximity to international ports of entry, prevalence of exotic flora or urban warming. We found a negative relationship between native and exotic bee abundance at sites with high total bee abundance, suggesting that exotic bees may negatively affect native bee populations. These effects were not driven by the numerically dominant exotic honeybee, but rather by other exotic bees. Our findings complicate the emerging paradigm of cities as key sites for pollinator conservation.

An ultrahigh-performance chromatography/tandem mass spectrometry quantitative method for trace analysis of potential endocrine disrupting steroid hormones in estuarine sediments.

RATIONALE: Estuaries are dynamic ecosystems, providing vital habitat for unique organisms of great ecological and commercial importance. The influx of natural and synthetic steroid hormones into estuaries poses risks to these organisms and to broader ecosystem health. However, detecting these trace level pollutants in estuarine water and sediment requires improved analytical techniques. METHODS: We describe an optimized ultrahigh-performance chromatography/tandem mass spectrometry (UHPLC/MS/MS) method for simultaneous quantitation of four classes of steroid hormones (estrogens, glucocorticoids, androgens and progestins) in sediment samples collected from an Alabama estuary. Sediment samples were homogenized using Hydromatrix (HM) sorbent and extracted with methanol and water (70%, v/v). Centrifuged extracts were purified using an Agilent Bond Elut QuEChERS dispersive-SPE kit to eliminate interfering substances that could negatively influence the ionization process. Chromatographic separation was achieved on a Poroshell 120 Phenyl-Hexyl column using an Agilent 1290 Infinity II UHPLC pump. Quantitation was carried out using an Agilent triple quadrupole mass spectrometer equipped with a JetStream/ESI source in dual mode. RESULTS: Chromatographic separation and better peak resolution were accomplished on an Agilent Poroshell 120 Phenyl-Hexyl column using a binary gradient method with a mobile phase consisting of 1 mM ammonium fluoride in water and a mixture of methanol/acetonitrile. A dynamic multiple reaction monitoring (MRM) method was developed by optimizing various MS parameters. The method was used to analyze target steroid hormones in estuarine sediments. A total of ten steroid hormones were detected at trace amounts in estuarine sediments. CONCLUSIONS: The optimized analytical method described here involves reasonably simple sample preparation and simultaneous trace level quantitation of four classes (estrogens, glucocorticoids, androgens and progestins) of steroid hormones in a single experimental run. Copyright © 2016 John Wiley & Sons, Ltd.

Tree species richness and ash density have variable effects on emerald ash borer biological control by woodpeckers and parasitoid wasps in post-invasion white ash stands.

Emerald ash borer (EAB) (Agrilus planipennis Fairmaire) (Coleoptera: Buprestidae) is the most destructive insect to invade North American forests. Identifying habitat features that support EAB natural enemies is necessary to enhance EAB biological control. In many forest ecosystems, tree species diversity has been linked with reduced pest abundance and increases in natural enemy abundance. We assessed the influence of tree species richness, ash density, and proportion of total ash basal area on ash canopy condition, EAB larval densities, and biocontrol by woodpeckers and parasitoids in pairs of healthy and declining overstory (DBH > 10 cm) and recruit-sized ash (DBH 2-10 cm) in 4 post-invasion forests in Michigan, USA. Tree species richness and ash density were not significantly associated with EAB larval densities, ash canopy dieback and transparency, and woodpecker predation of EAB larvae. In declining and healthy overstory ash, woodpeckers killed 38.5 ±â€…3.9% and 13.2 ±â€…3.7% of larvae, respectively, while the native parasitoid Phasgonophora sulcata Westwood killed 15.8 ±â€…3.8% and 8.3 ±â€…3.0% and the introduced parasitoid Spathius galinae Belokobylskij & Strazanac killed 10.8 ±â€…2.5% and 5.0 ±â€…2.6% of EAB larvae. Parasitism by P. sulcata was inversely related to ash density while parasitism by S. galinae was positively associated with ash density. Ash density, but not tree diversity, appears to differentially influence biological control of EAB by parasitoids, but this effect is not associated with reduced EAB densities or improved canopy condition.

Motor Processing in Children With Cochlear Implants as Assessed by Functional Near-Infrared Spectroscopy.

Auditory-motor and visual-motor networks are often coupled in daily activities, such as when listening to music and dancing; but these networks are known to be highly malleable as a function of sensory input. Thus, congenital deafness may modify neural activities within the connections between the motor, auditory, and visual cortices. Here, we investigated whether the cortical responses of children with cochlear implants (CI) to a simple and repetitive motor task would differ from that of children with typical hearing (TH) and we sought to understand whether this response related to their language development. Participants were 75 school-aged children, including 50 with CI (with varying language abilities) and 25 controls with TH. We used functional near-infrared spectroscopy (fNIRS) to record cortical responses over the whole brain, as children squeezed the back triggers of a joystick that vibrated or not with the squeeze. Motor cortex activity was reflected by an increase in oxygenated hemoglobin concentration (HbO) and a decrease in deoxygenated hemoglobin concentration (HbR) in all children, irrespective of their hearing status. Unexpectedly, the visual cortex (supposedly an irrelevant region) was deactivated in this task, particularly for children with CI who had good language skills when compared to those with CI who had language delays. Presence or absence of vibrotactile feedback made no difference in cortical activation. These findings support the potential of fNIRS to examine cognitive functions related to language in children with CI.

Cross-modal plasticity in children with cochlear implant: converging evidence from EEG and functional near-infrared spectroscopy.

Over the first years of life, the brain undergoes substantial organization in response to environmental stimulation. In a silent world, it may promote vision by (i) recruiting resources from the auditory cortex and (ii) making the visual cortex more efficient. It is unclear when such changes occur and how adaptive they are, questions that children with cochlear implants can help address. Here, we examined 7-18 years old children: 50 had cochlear implants, with delayed or age-appropriate language abilities, and 25 had typical hearing and language. High-density electroencephalography and functional near-infrared spectroscopy were used to evaluate cortical responses to a low-level visual task. Evidence for a 'weaker visual cortex response' and 'less synchronized or less inhibitory activity of auditory association areas' in the implanted children with language delays suggests that cross-modal reorganization can be maladaptive and does not necessarily strengthen the dominant visual sense.

Scale Insects Support Natural Enemies in Both Landscape Trees and Shrubs Below Them.

Scale insects are frequently abundant on urban trees. Although scales can worsen tree condition, some tree species tolerate moderate scale densities. Scales are prey for many natural enemies. Therefore, scale-infested trees may conserve natural enemies in their canopies and in nearby plants. We examined if scale-infested oaks-Quercus phellos L.-hosted more natural enemies than scale-uninfested oaks-Q. acutissima Carruth. and Q. lyrata Walter in Raleigh, NC. USA. We also tested if natural enemies were more abundant in holly shrubs (Ilex spp.) planted below scale-infested compared to scale-uninfested oaks. We collected natural enemies from the canopies of both tree types and from holly shrubs planted below these trees. To determine if tree type affected the abundance of natural enemies that passively dispersed to shrubs, we created hanging cup traps to collect arthropods as they fell from trees. To determine if natural enemies became more abundant on shrubs below scale-infested compared to scale-uninfested trees over short time scales, we collected natural enemies from holly shrubs below each tree type at three to six-day intervals. Scale-infested trees hosted more natural enemies than scale-uninfested trees and shrubs below scale-infested trees hosted more natural enemies than shrubs under scale-uninfested trees. Natural enemy abundance in hanging cup traps did not differ by tree type; however, shrubs underneath scale-infested trees accumulated more natural enemies than shrubs under scale-uninfested trees in six to nine days. Tolerating moderate pest densities in urban trees may support natural enemy communities, and thus biological control services, in shrubs below them.

Comparison of Dental Injury Rates in Perioperative Intubation and Suspension Laryngoscopy for Otolaryngology Procedures.

OBJECTIVE: Direct laryngoscopy is an essential skill during perioperative intubation and otolaryngology procedures. Dental injury is a common complication of direct laryngoscopy. However, the technique and tools used by anesthesiologists, nurse anesthetists, and others during perioperative intubation and by ear, nose, and throat surgeons for their procedures are different. The purpose of this review is to explore the literature for all studies detailing rates of dental injury in each of these settings and to compare them to see if the approaches have a significant difference in rate of dental injury. DATA SOURCES: PubMed. REVIEW METHODS: A comprehensive search of PubMed was performed through February 2021 with search terms "dental" and "intubation" or "laryngoscopy." PRISMA guidelines were followed. Studies documenting rates of dental injuries during intubation or during laryngologic procedures were included, and the 2 groups were compared. RESULTS: Twenty-three studies met inclusion criteria: 17 in the perioperative intubation group and 6 in the suspension laryngoscopy group. There was an increased incidence of dental injury in the perioperative intubation group (4.86%) as compared with the suspension laryngoscopy group (1.70%). CONCLUSIONS: The difference in dental injury rate between the groups could be due to the differences in direct laryngoscopy technique or tools used, the presence vs absence of a dental guard, or a combination of these factors. More studies need to be performed to develop definitive and specific conclusions to recommend changes that prevent dental injury.

Sinonasal immunoglobin G4-related disease: case report and review.

Immunoglobin G4-related disease (IgG4-RD) is a chronic fibro-inflammatory condition that presents as a single or multiple tumefactive lesions affecting virtually any organ system. Here we report a case of recurrent sinonasal IgG4-RD and review the literature of this evolving entity.

Factors Associated with Speech-Recognition Performance in School-Aged Children with Cochlear Implants and Early Auditory-Verbal Intervention.

BACKGROUND: Considerable variability exists in the speech recognition abilities achieved by children with cochlear implants (CIs) due to varying demographic and performance variables including language abilities. PURPOSE: This article examines the factors associated with speech recognition performance of school-aged children with CIs who were grouped by language ability. RESEARCH DESIGN: This is a single-center cross-sectional study with repeated measures for subjects across two language groups. STUDY SAMPLE: Participants included two groups of school-aged children, ages 7 to 17 years, who received unilateral or bilateral CIs by 4 years of age. The High Language group (N = 26) had age-appropriate spoken-language abilities, and the Low Language group (N = 24) had delays in their spoken-language abilities. DATA COLLECTION AND ANALYSIS: Group comparisons were conducted to examine the impact of demographic characteristics on word recognition in quiet and sentence recognition in quiet and noise. RESULTS: Speech recognition in quiet and noise was significantly poorer in the Low Language compared with the High Language group. Greater hours of implant use and better adherence to auditory-verbal (AV) therapy appointments were associated with higher speech recognition in quiet and noise. CONCLUSION: To ensure maximal speech recognition in children with low-language outcomes, professionals should develop strategies to ensure that families support full-time CI use and have the means to consistently attend AV appointments.

SMARCE1-related Coffin-Siris Syndrome: Case report and otolaryngologic manifestations of the syndrome.

Coffin-Siris Syndrome (CSS) is a genetic syndrome associated with multiple congenital anomalies due to mutations in the BAF-complex or SOX gene. Although well characterized overall, the subunits of the BAF-complex or SOX gene affected demonstrate phenotypic differences which are continuing to be defined. Among the variants is the SMARCE1 mutation, the least common identified genotype. This case report presents a pediatric patient with SMARCE1-related CSS, the seventh case reported in the literature. The congenital anomalies are discussed and compared to the reported cases of SMARCE1-related CSS and CSS overall with an emphasis on otolaryngologic manifestations.

Rosette-forming glioneuronal tumor: an illustrative case and a systematic review.

BACKGROUND: Rosette-forming glioneuronal tumors (RGNTs) are rare, low-grade, primary CNS tumors first described in 2002 by Komori et al. RGNTs were initially characterized as a World Health Organization (WHO) grade I tumors typically localized to the fourth ventricle. Although commonly associated with an indolent course, RGNTs have the potential for aggressive behavior. METHODS: A comprehensive search of PubMed and Web of Science was performed through November 2019 using the search term "rosette-forming glioneuronal tumor." Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. English, full-text case reports and series with histopathological confirmation were included. Patient demographics, presentations, MRI features, tumor location, treatment, and follow-up of all 130 cases were extracted. RESULTS: A 19-year-old man with a history of epilepsy and autism presented with acute hydrocephalus. MRI scans from 2013 to 2016 demonstrated unchanged abnormal areas of cortex in the left temporal lobe with extension into the deep gray-white matter. On presentation to our clinic in 2019, the lesion demonstrated significant progression. The patient's tumor was identified as RGNT, WHO grade I. One hundred thirty patients were identified across 80 studies. CONCLUSION: RGNT has potential to transform from an indolent tumor to a tumor with more aggressive behavior. The results of our systematic review provide insight into the natural history and treatment outcomes of these rare tumors.

The effects of urbanization on bee communities depends on floral resource availability and bee functional traits.

Wild bees are important pollinators in many ecosystems threatened by anthropogenic disturbance. Urban development can reduce and degrade natural habitat for bees and other pollinators. However, some researchers suggest that cities could also provide refuge for bees, given that agricultural intensification may pose a greater risk. In this study, we surveyed bee communities at 15 farms and gardens across an urban-rural gradient in southeastern Michigan, USA to evaluate the effect of urbanization on bees. We examined how floral resources, bee functional traits, temperature, farm size, and the spatial scale of analysis influence bee response to urbanization. We found that urbanization positively affected bee diversity and evenness but had no effect on total abundance or species richness. Additionally, urbanization altered bee community composition via differential effects on bee species and functional groups. More urbanized sites supported a greater number of exotic, above-ground nesting, and solitary bees, but fewer eusocial bees. Blooming plant species richness positively influenced bee species diversity and richness. Furthermore, the amount of available floral resources was positively associated with exotic and eusocial bee abundances. Across sites, nearly 70% of floral resources were provided by exotic plants, most of which are characterized as weedy but not invasive. Our study demonstrates that urbanization can benefit some bee species and negatively impact others. Notably, Bombus and Lasioglossum (Dialictus), were two important pollinator groups negatively affected by urbanization. Our study supports the idea that urban environments can provide valuable habitat for diverse bee communities, but demonstrates that some bees are vulnerable to urbanization. Finally, while our results indicate that increasing the abundance and richness of floral resources could partially compensate for negative effects of urbanization on bees, the effectiveness of such measures may be limited by other factors, such as urban warming.

Thyroid surgery YouTube videos: estimating quality by surgeon characteristics and view rate.

BACKGROUND: With readily available material online we aimed: (I) to estimate the volume of thyroid surgery-related video content readily available to the surgical trainee; (II) to stratify the sources of thyroid surgery-related video content by source (patient, institution, surgeon, or other) and (III) to estimate the quality of the surgeon source by related scholarly output. METHODS: A search of YouTube, a widely used source of open-access video content, was undertaken using "thyroidectomy" as the search term. The first 100 "hits" were analyzed for source. When the video was surgeon-sourced, the surgeon's name was used in a PubMed author query for "thyroidectomy" and publications noted. RESULTS: Approximately 7,260 videos were returned using "thyroidectomy" as the search term. The first 100 "hits" were stratified by source, assuming the typical surgical trainee would not delve further into the list. The sources were primarily surgeons, followed by patient testimonials, and institutions. The surgeons were stratified by related publications listed in PubMed. The majority of surgeons were not published in thyroid surgery-related topics. CONCLUSIONS: Internet video content is an increasingly utilized source of surgical education. Since video content can be posted without peer review or confirmation of veracity, this study measures the variety of sources of thyroid surgery information. Individuals without thyroid surgery publication history posted the majority of surgeon-sourced video content, although this history serves only as a surrogate for an academic career. Trainees and educators alike should critically analyze the quality of video content.

Making Sense of Clinical Laboratory Results: An Analysis of Questions and Replies in a Social Q&A Community.

Previous literature has revealed that patients have difficulty making sense of their clinical data. To address this barrier, we first need to understand what kinds of support that patients may seek. In this study, we analyzed question posts and their replies in a social Q&A community to understand what types of support people are providing to and receiving from the community and what contextual information they provide in order to elicit relevant answers.

A rapid UHPLC-MS/MS method for quantitation of phytoestrogens and the distribution of enterolactone in an Alabama estuary.

Endocrine disrupting chemicals (EDCs) are natural or synthetic compounds that can interfere with the endocrine systems of humans and wildlife. EDCs can pass through wastewater treatment systems, or run off from urban areas or agricultural operations, into natural water bodies, exposing resident and migratory organisms to complex EDC mixtures. Some phytoestrogenic polyphenolics (PEPP) are known or suspected EDCs; however, their contribution to total EDC burden in natural surface water systems is largely unknown. We describe a rapid, sensitive, and reproducible quantitative method for analysis of 15 PEPP in estuarine sediment and water, using ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS). The method provides excellent peak resolution, peak separation, and rapid run times (method separation/total run time: 8/12.5 min). With two exceptions, spiking experiments demonstrated that the percent recoveries for target PEPP in sediment and water samples were within acceptable analytical validation limits. LOD and LOQ values ranged from 0.004 to 0.010 ng/injection and 0.013-0.032 ng/injection, respectively. The validated method was used for PEPP analysis of sediment and water samples collected from 11 locations within the Perdido Bay estuary in coastal Alabama. No PEPP above the LOD were detected in sediment samples. The mammalian-derived lignin enterolactone was observed at low concentrations in water throughout the estuary, and significantly, at elevated concentrations at two locations associated with small-scale septic systems (3.66 ±â€¯0.27 ng L-1 and 4.01 ±â€¯0.33 ng L-1) and a large wastewater treatment system (4.56 ±â€¯0.24 ng L-1 and 5.69 ±â€¯0.43 ng L-1).

Minocycline fails to improve neurologic and histologic outcome after ventricular fibrillation cardiac arrest in rats.

BACKGROUND: Prolonged cardiac arrest (CA) produces extensive neuronal death and microglial proliferation and activation resulting in neuro-cognitive disabilities. Among other potential mechanisms, microglia have been implicated as triggers of neuronal death after hypoxic-ischemic insults. Minocycline is neuroprotective in some brain ischemia models, either by blunting the microglial response or by a direct effect on neurons. AIM: To improve survival, attenuate neurologic deficits, neuroinflammation, and histological damage after ventricular fibrillation (VF) CA in rats. METHODS: Adult male isoflurane-anesthetized rats were subjected to 6 min VF CA followed by 2 min resuscitation including chest compression, epinephrine, bicarbonate, and defibrillation. After return of spontaneous circulation (ROSC), rats were randomized to two groups: (1) Minocycline 90 mg/kg intraperitoneally (i.p.) at 15 min ROSC, followed by 22.5 mg/kg i.p. every 12 h for 72 h; and (2) Controls, receiving the same volume of vehicle (phosphate-buffered saline). The rats were kept normothermic during the postoperative course. Neurologic injury was assessed daily using Overall Performance Category (OPC; 1 = normal, 5 = dead) and Neurologic Deficit Score (NDS; 0% = normal, 100% = dead). Rats were sacrificed at 72 h. Neuronal degeneration (Fluoro-Jade C staining) and microglia proliferation (anti-Iba-1 staining) were quantified in four selectively vulnerable brain regions (hippocampus, striatum, cerebellum, cortex) by three independent reviewers masked to the group assignment. RESULTS: In the minocycline group, 8 out of 14 rats survived to 72 h compared to 8 out of 19 rats in the control group (P = 0.46). The degree of neurologic deficit at 72 h [median, (interquartile range)] was not different between survivors in minocycline vs controls: OPC 1.5 (1-2.75) vs 2 (1.25-3), P = 0.442; NDS 12 (2-20) vs 17 (7-51), P = 0.328) or between all studied rats. The number of degenerating neurons (minocycline vs controls, mean ± SEM: Hippocampus 58 ± 8 vs 76 ± 8; striatum 121 ± 43 vs 153 ± 32; cerebellum 20 ± 7 vs 22 ± 8; cortex 0 ± 0 vs 0 ± 0) or proliferating microglia (hippocampus 157 ± 15 vs 193 cortex 0 ± 0 vs 0 ± 0; 16; striatum 150 ± 22 vs 161 ± 23; cerebellum 20 ± 7 vs 22 ± 8; cortex 26 ± 6 vs 31 ± 7) was not different between groups in any region (all P > 0.05). Numerically, there were approximately 20% less degenerating neurons and proliferating microglia in the hippocampus and striatum in the minocycline group, with a consistent pattern of histological damage across the individual regions of interest. CONCLUSION: Minocycline did not improve survival and failed to confer substantial benefits on neurologic function, neuronal loss or microglial proliferation across multiple brain regions in our model of rat VF CA.

A rapid UHPLC-MS/MS method for simultaneous quantitation of 23 perfluoroalkyl substances (PFAS) in estuarine water.

Per- and polyfluoroalkyl substances (PFAS) represent a large group of synthetic organic compounds which, as a result of their unique chemical properties, render them extremely recalcitrant to environmental degradation. Research concerning the environmental, ecological, and human health effects of PFAS has focused on long aliphatic chain (> C7) compounds having no ether bonds. For new, less studied, or previously unknown PFAS (≤ C7 with ether bonds), there is little to no information about their environmental behavior, transport, fate, exposure, and toxicological effects. LC-MS/MS has proven effective for detection and quantitation of some PFAS, however, straightforward analytical methods for simultaneous trace quantitation of broad mixtures of PFAS in varied complex environmental media, available to a wide range of researchers and also suitable for routine monitoring, remain critical needs. Here we describe a simple, rapid, sensitive, and reproducible quantitative analytical method for trace analysis and monitoring of 23 PFAS in estuarine water, using ultra-high performance liquid chromatography-triple quadrupole mass spectrometry (UHPLC-MS/MS). The developed MRM method allows simultaneous trace quantitation of a broad mixture of PFAS, including 13 perfluoroalkyl carboxylic acids, 8 perfluoroalkyl sulfonates, and 2 short-chain perfluoroethers. The method provides better peak resolution and peak separation, and shorter run times (method separation/total run time: 6/8 min) compared to those of existing analytical methods. Percent recoveries for the validated method ranged from 78.54 to 112.61. LOD and LOQ values ranged from 0.48 to 1.68 pg/injection and 1.71 to 5.40 pg/injection, respectively. The validated method was used for quantitative PFAS analysis of estuarine water samples collected from 16 locations within the Perdido Bay estuary in coastal Alabama.

Revisiting the particular role of host shifts in initiating insect speciation.

The notion that shifts to new hosts can initiate insect speciation is more than 150 years old, yet widespread conflation with paradigms of sympatric speciation has led to confusion about how much support exists for this hypothesis. Here, we review 85 insect systems and evaluate the relationship between host shifting, reproductive isolation, and speciation. We sort insects into five categories: (1) systems in which a host shift has initiated speciation; (2) systems in which a host shift has made a contribution to speciation; (3) systems in which a host shift has caused the evolution of new reproductive isolating barriers; (4) systems with host-associated genetic differences; and (5) systems with no evidence of host-associated genetic differences. We find host-associated genetic structure in 65 systems, 43 of which show that host shifts have resulted in the evolution of new reproductive barriers. Twenty-six of the latter also support a role for host shifts in speciation, including eight studies that definitively support the hypothesis that a host shift has initiated speciation. While this review is agnostic as to the fraction of all insect speciation events to which host shifts have contributed, it clarifies that host shifts absolutely can and do initiate speciation.