Plasma Levels of Bevacizumab and Vascular Endothelial Growth Factor After Low-Dose Bevacizumab Treatment for Retinopathy of Prematurity in Infants

Importance

Intravitreal bevacizumab effectively treats severe retinopathy of prematurity (ROP), but it enters the bloodstream and may reduce serum vascular endothelial growth factor (VEGF), potentially causing detrimental effects on developing organs in the premature infant.

Objective

To evaluate the association of intravitreal bevacizumab with plasma bevacizumab and VEGF concentrations at 2 and 4 weeks after predefined, de-escalating doses of intravitreal bevacizumab were administered to infants with severe ROP.

Design, Setting, and Participants

This phase 1 dose de-escalation case series study was conducted at 10 US hospitals of ophthalmology institutions from May 21, 2015, to May 7, 2019. Blood samples were collected 2 and 4 weeks after intravitreal bevacizumab injection. Participants included 83 premature infants with type 1 ROP in 1 or both eyes and no previous ROP treatment. Data were analyzed from April 2017 to August 2021.

Interventions

Study eyes received a single bevacizumab injection of 0.250 mg, 0.125 mg, 0.063 mg, 0.031 mg, 0.016 mg, 0.008 mg, 0.004 mg, or 0.002 mg. When the fellow eye required treatment, one dose higher was administered. Total dose administered at baseline was defined as the sum of doses given to each eye within 3 days of initial study-eye injection.

Main Outcomes and Measures

Plasma bevacizumab concentration at 2 and 4 weeks after injection and the percentage change in plasma VEGF concentrations from pretreatment levels.

Results

A total of 83 infants (mean [SD] age, 25 [2] weeks; 48 boys [58%]) were included in this study. Higher doses of bevacizumab administered at baseline were associated with higher plasma bevacizumab concentrations at 2 weeks (ρ, 0.53; 95% CI, 0.31-0.70) and 4 weeks (ρ, 0.44; 95% CI, 0.18-0.64). Plasma VEGF concentrations decreased by 50% or more from pretreatment levels in 40 of 66 infants (61%) at 2 weeks and 31 of 61 infants (51%) at 4 weeks, but no association was observed between the total dose of bevacizumab administered at baseline and percentage change in plasma VEGF concentrations 2 weeks (ρ, -0.04; 95% CI, -0.28 to 0.20) or 4 weeks (ρ, -0.17; 95% CI, -0.41 to 0.08) after injection.

Conclusions and Relevance

Results of this phase 1 dose de-escalation case series study revealed that bevacizumab doses as low as 0.002 mg were associated with reduced plasma VEGF levels for most infants at 2 and 4 weeks after intravitreal administration; however, no association was observed between total bevacizumab dose administered and reductions in plasma VEGF levels from preinjection to 2 weeks or 4 weeks. Additional studies are needed to evaluate the long-term effects of low-dose bevacizumab on neurodevelopment and retinal structure.

Visual Outcomes and Complications After Lensectomy for Traumatic Cataract in Children

Importance

The Pediatric Eye Disease Investigator Group Cataract Registry provides a multicenter assessment of visual outcomes and complications after lensectomy for traumatic pediatric cataract.

Objective

To report visual acuity (VA) and the cumulative proportion with strabismus, glaucoma, and other ocular complications by 15 months after lensectomy for traumatic cataract among children younger than 13 years at the time of surgery.

Design, Setting, and Participants

From June 18, 2012, to July 8, 2015, 1266 eyes of 994 children from 33 pediatric eye care practices seen within 45 days after lensectomy were enrolled in a multicenter, prospective observational registry. Of these, 74 eyes of 72 participants undergoing lensectomy for traumatic cataract were included in a cohort study. Follow-up was completed by November 2, 2015, and data were analyzed from March 20, 2018, to July 7, 2020.

Exposures

Lensectomy after ocular trauma.

Main Outcomes and Measures

Best-corrected VA from 9 to 15 months after lensectomy for traumatic cataract (for those 3 years or older) and the cumulative proportion with strabismus, glaucoma, and other ocular complications by 15 months.

Results

Of 994 participants in the registry, 84 (8%) had traumatic cataract. The median age at lensectomy for 72 participants examined within 15 months after surgery was 7.3 (range, 0.1-12.6) years; 46 (64%) were boys. An intraocular lens was placed in 57 of 74 eyes (77%). In children 3 years or older at outcome, the median best-corrected VA was 20/250 (range, 20/20 to worse than 20/800) in 6 eyes with aphakia and 20/63 (range, 20/20 to 20/200) in 26 eyes with pseudophakia. Postoperative visual axis opacification was reported in 18 of 27 eyes with pseudophakia without primary posterior capsulotomy (15-month cumulative proportion, 77%; 95% CI, 58%-92%). The cumulative proportion with strabismus was 43% (95% CI, 31%-58%) in 64 participants with ocular alignment data; exotropia was present in 14 of 23 participants (61%). The cumulative proportion with glaucoma was 6% (95% CI, 2%-16%).

Conclusions and Relevance

Trauma was not a common cause of pediatric cataract requiring surgery. For children with traumatic cataract, substantial ocular morbidity including permanent vision loss was found, and long-term eye and vision monitoring are needed for glaucoma, strabismus, and capsular opacification.

Overminus Lens Therapy for Children 3 to 10 Years of Age With Intermittent Exotropia: A Randomized Clinical Trial

Importance

This is the first large-scale randomized clinical trial evaluating the effectiveness and safety of overminus spectacle therapy for treatment of intermittent exotropia (IXT).

Objective

To evaluate the effectiveness of overminus spectacles to improve distance IXT control.

Design, Setting, and Participants

This randomized clinical trial conducted at 56 clinical sites between January 2017 and January 2019 associated with the Pediatric Eye Disease Investigator Group enrolled 386 children aged 3 to 10 years with IXT, a mean distance control score of 2 or worse, and a refractive error between 1.00 and -6.00 diopters (D). Data analysis was performed from February to December 2020.

Interventions

Participants were randomly assigned to overminus spectacle therapy (-2.50 D for 12 months, then -1.25 D for 3 months, followed by nonoverminus spectacles for 3 months) or to nonoverminus spectacle use.

Main Outcomes and Measures

Primary and secondary outcomes were the mean distance IXT control scores of participants examined after 12 months of treatment (primary outcome) and at 18 months (3 months after treatment ended) assessed by an examiner masked to treatment group. Change in refractive error from baseline to 12 months was compared between groups. Analyses were performed using the intention-to-treat population.

Results

The mean (SD) age of 196 participants randomized to overminus therapy and 190 participants randomized to nonoverminus treatment was 6.3 (2.1) years, and 226 (59%) were female. Mean distance control at 12 months was better in participants treated with overminus spectacles than with nonoverminus spectacles (1.8 vs 2.8 points; adjusted difference, -0.8; 95% CI, -1.0 to -0.5; P < .001). At 18 months, there was little or no difference in mean distance control between overminus and nonoverminus groups (2.4 vs 2.7 points; adjusted difference, -0.2; 95% CI, -0.5 to 0.04; P = .09). Myopic shift from baseline to 12 months was greater in the overminus than the nonoverminus group (-0.42 D vs -0.04 D; adjusted difference, -0.37 D; 95% CI, -0.49 to -0.26 D; P < .001), with 33 of 189 children (17%) in the overminus group vs 2 of 169 (1%) in the nonoverminus group having a shift higher than 1.00 D.

Conclusions and Relevance

Children 3 to 10 years of age had improved distance exotropia control when assessed wearing overminus spectacles after 12 months of overminus treatment; however, this treatment was associated with increased myopic shift. The beneficial effect of overminus lens therapy on distance exotropia control was not maintained after treatment was tapered off for 3 months and children were examined 3 months later.

Trial Registration

ClinicalTrials.gov Identifier: NCT02807350.

Secondary 12-Month Ocular Outcomes of a Phase 1 Dosing Study of Bevacizumab for Retinopathy of Prematurity

Importance

Lower bevacizumab dosages are being used for type 1 retinopathy of prematurity, but there are limited data on long-term ocular outcomes with lower doses.

Objective

To evaluate ocular outcomes at 12 months' corrected age for eyes that received a dose of 0.625 mg, 0.25 mg, 0.125 mg, 0.063 mg, or 0.031 mg of bevacizumab for type 1 retinopathy of prematurity.

Design, Setting, and Participants

This prospective cohort study used a masked, multicenter, phase 1 dose de-escalation study design and was conducted from April 2016 to October 2017. Study eyes were treated with a dose of 0.25, 0.125, 0.063, or 0.031 mg of bevacizumab; fellow eyes were treated with a dosage 1 level higher than the study eye. Additional treatment after 4 weeks was at investigator discretion. Data analysis occurred from November 2018 to March 2019.

Interventions

Intravitreous bevacizumab injections of 0.625 mg to 0.031 mg.

Main Outcomes and Measures

Visual fixation, amblyopia, alignment, nystagmus, cycloplegic refraction, and ocular examinations were assessed at 12 months' corrected age as preplanned secondary outcomes. The primary outcome 4 weeks after treatment and secondary outcomes after 6 months' corrected age have been previously reported.

Results

Forty-six of 61 infants (75%) had a 12-month follow-up examination (46 study eyes and 43 fellow eyes; median [interquartile range] birth weight, 650 [590-760] g). Of 87 eyes with a cycloplegic refraction, 12 (14% [95% CI, 7%-27%]) had myopia of more than -5.00 D spherical equivalent; 2 (2%; [95% CI, 0%-8%]) had hyperopia greater than 5.00 D spherical equivalent; and 5 infants (11% [95% CI, 4%-24%]) had anisometropia greater than 1.50 D spherical equivalent. Abnormalities of the cornea, lens, or anterior segment were reported in 1 eye (1% [95% CI, 0%-6%]), 3 eyes (3% [95% CI, 1%-10%]), and 3 eyes (3% [95% CI, 1%-10%]), respectively. Optic nerve atrophy was identified in 11 eyes (13% [95% CI, 6%-26%]), and 1 eye (1% [95% CI, 0%-6%]) had total retinal detachment. Strabismus was reported in 13 infants (30% [95% CI, 17%-45%]), manifest nystagmus in 7 infants (15% [95% CI, 6%-29%]), and amblyopia in 3 infants (7% [95% CI, 1%-18%]). Overall, 98% of infants had central fixation in each eye (44 of 45 eyes).

Conclusions and Relevance

In this study of low-dose bevacizumab, the secondary outcomes of high myopia, strabismus, retinal detachment, nystagmus, and other ocular abnormalities at 1 year were consistent with rates reported in other studies with higher dosages.

Trial Registration

ClinicalTrials.gov identifier: NCT02390531.

A Randomized Trial Evaluating Short-term Effectiveness of Overminus Lenses in Children 3 to 6 Years of Age with Intermittent Exotropia

PURPOSE

To evaluate the short-term effectiveness of overminus spectacles in improving control of childhood intermittent exotropia (IXT).

DESIGN

Randomized, clinical trial.

PARTICIPANTS

A total of 58 children aged 3 to <7 years with IXT. Eligibility criteria included a distance control score of 2 or worse (mean of 3 measures during a single examination) on a scale of 0 (exophoria) to 5 (constant exotropia) and spherical equivalent refractive error between -6.00 diopters (D) and +1.00 D.

METHODS

Children were randomly assigned to overminus spectacles (-2.50 D over cycloplegic refraction) or observation (non-overminus spectacles if needed or no spectacles) for 8 weeks.

MAIN OUTCOME MEASURES

The primary outcome was distance control score for each child (mean of 3 measures during a single examination) assessed by a masked examiner at 8 weeks. Outcome testing was conducted with children wearing their study spectacles or plano spectacles for the children in the observation group who did not need spectacles. The primary analysis compared mean 8-week distance control score between treatment groups using an analysis of covariance model that adjusted for baseline distance control, baseline near control, prestudy spectacle wear, and prior IXT treatment. Treatment side effects were evaluated using questionnaires completed by parents.

RESULTS

At 8 weeks, mean distance control was better in the 27 children treated with overminus spectacles than in the 31 children who were observed without treatment (2.0 vs. 2.8 points, adjusted difference = -0.75 points favoring the overminus group; 2-sided 95% confidence interval, -1.42 to -0.07 points). Side effects of headaches, eyestrain, avoidance of near activities, and blur appeared similar between treatment groups.

CONCLUSIONS

In a pilot randomized clinical trial, overminus spectacles improved distance control at 8 weeks in children aged 3 to <7 years with IXT. A larger and longer randomized trial is warranted to assess the effectiveness of overminus spectacles in treating IXT, particularly the effect on control after overminus treatment has been discontinued.

Dual targeting of EGFR and ERBB2 pathways produces a synergistic effect on cancer cell proliferation and migration in vitro

Members of the epidermal growth factor receptor (EGFR/ERBB) gene family are frequently dysregulated in a range of human cancers, and therapeutics targeting these proteins are in clinical use. We hypothesized that similar pathways are involved in feline and canine tumours and that the same drugs may be of clinical use in veterinary patients. We investigated EGFR and ERBB2 targeting using a panel of feline and canine cell lines. EGFR and ERBB2 were targeted with siRNAs or tyrosine kinase inhibitors (TKIs) and their effect on cellular proliferation, colony formation and migration was investigated in vitro. Here we report that EGFR and ERBB2 combined siRNA targeting produced synergistic effects in feline and canine cell lines similar to that reported in human cell lines. We conclude that dual EGFR and ERBB2 targeting using TKIs should be further evaluated as a potential new therapeutic strategy in feline head and neck and mammary tumours and canine mammary tumours.

Effect of Seed Blends and Soil-Insecticide on Western and Northern Corn Rootworm Emergence from mCry3A+eCry3.1Ab Bt Maize

Seed blends containing various ratios of transgenic Bt maize (Zea mays L.) expressing the mCry3A+eCry3.1Ab proteins and non-Bt maize (near-isoline maize) were deployed alone and in combination with a soil applied pyrethroid insecticide (Force CS) to evaluate the emergence of the western corn rootworm, Diabrotica virgifera virgifera LeConte, in a total of nine field environments across the Midwestern United States in 2010 and 2011. Northern corn rootworm, Diabrotica barberi Smith & Lawrence emergence was also evaluated in four of these environments. Both western and northern corn rootworm beetle emergence from all Bt treatments was significantly reduced when compared with beetle emergence from near-isoline treatments. Averaged across all environments, western corn rootworm beetle emergence from 95:5, 90:10, and 80:20 seed blend ratios of mCry3A+eCry3.1Ab: near-isoline were 2.6-, 4.2-, and 6.7-fold greater than that from the 100:0 ratio treatment. Northern corn rootworm emergence from the same seed blend treatments resulted in 2.8-, 3.2-, and 4.2-fold more beetles than from the 100:0 treatment. The addition of Force CS (tefluthrin) significantly reduced western corn rootworm beetle emergence for each of the three treatments to which it was applied. Force CS also significantly delayed the number of days to 50% beetle emergence in western corn rootworms. Time to 50% beetle emergence in the 100% mCry3A+eCry3.1Ab treatment with Force CS was delayed 13.7 d when compared with western corn rootworm beetle emergence on near-isoline corn. These data are discussed in terms of rootworm resistance management.

Corneal injuries from liquid detergent pods

Laundry and dishwasher detergent "pods" were introduced to the United States market in 2010 and are sold by several manufacturers. They represent a high percentage of household cleaning product exposure in the United Kingdom. We present a consecutive case series of 10 children seen in a 9-month period with corneal injuries from exposure to liquid detergent pods.

Modeling a western corn rootworm, Diabrotica virgifera virgifera (Coleoptera: Chrysomelidae), maturation delay and resistance evolution in Bt corn

BACKGROUND

Emergence delay and female-skewed sex ratios among adults of Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) from Bt corn have been reported in field studies. The authors used a simulation model to study the effect of a maturation delay and a female-skewed sex ratio for D. v. virgifera emerging from Bt corn on the evolution of Bt resistance.

RESULTS

The effect of skewed toxin mortality in one sex on evolution of Bt resistance was insignificant. An emergence delay among resistant beetles from Bt corn slowed resistance evolution. A shift in the time of emergence for homozygous susceptible beetles from Bt corn did not have a significant effect on the evolution of Bt resistance in D. v. virgifera.

CONCLUSION

This simulation study suggested that skewed toxin mortality in one sex and an emergence delay for beetles in Bt corn are not major concerns for managing resistance by D. v. virgifera to single-toxin or pyramided Bt corn.

A comparative life-table analysis of Sipha flava (Hemiptera: Aphididae) on two biofuel hosts, Miscanthus x giganteus and Saccharum spp

Among the insects reported in biofuel crops, the yellow sugarcane aphid, Sipha flava (Forbes), is a potential pest of giant miscanthus, Miscanthus x giganteus Greef et Deu ex Hodkinson et Renvoize (M x g) and energy cane 'L79-1002', Saccharum spp. L. We studied the biology of S. flava on M x g and energy cane and estimated the development period, fecundity, longevity, intrinsic rate of increase, doubling time, reproductive value, and survivorship curves. To demonstrate the host suitability in a susceptible species, we studied the aphid life table on sorghum 'PL 18200,' Sorghum bicolor (L.) Moench. Life-table information was recorded under greenhouse conditions on the host plants. Our results suggested that both M x g and energy cane are suitable hosts for S. flava. We observed similar aphid development period on both hosts. Life-table estimates including longevity and fecundity suggested that M x g is a more suitable host for the aphid than energy cane. The intrinsic rate of increase for S. flava was lower on energy cane (0.231) than on M x g (0.258).

Effect of Bt maize and soil insecticides on yield, injury, and rootworm survival: implications for resistance management

A 2-yr field experiment was conducted to determine the effects on Diabrotica spp. (Coleoptera: Chrysomelidae) of an insecticidal seed treatment (Poncho 1250, (AI)/clothianidin) and a granular insecticide (Aztec 2.1G, (AI)/tebupirimphos and cyfluthrin) alone and in combination with maize producing the insectidical toxin Cry3Bb1 derived from the bacterium Bacillus thuringiensis (Bt). Yields for Bt maize plots were significantly greater than for non-Bt maize; however, insecticides did not significantly affect yield. Insecticides significantly decreased root injury in non-Bt maize plots, but there were no significant differences in root injury between Bt maize with or without either insecticide. Maize producing the Bt toxin Cry3Bb1 and the soil-applied insecticide Aztec significantly decreased survival of western corn rootworm (Diabrotica virgifera virgifera LeConte), while only Bt maize significantly decreased survival of the northern corn rootworm (Diabrotica barberi Smith & Lawrence). For both species, Bt maize and each of the insecticides delayed emergence. In the absence of density-dependent mortality, Bt maize imposed 71 and 80% reduction in survival on the western corn rootworm and the northern corn rootworm, respectively. The data from this study do not support combining insecticide with Bt maize because the addition of insecticide did not increase yield or reduce root injury for Bt maize, and the level of rootworm mortality achieved with conventional insecticide was likely too low to delay the evolution of Bt resistance. In addition, delays in emergence from Bt maize combined with insecticides could promote assortative mating among Bt-selected individuals, which may hasten resistance evolution.

Primary uveal melanoma in a 4-year-old black child

Primary uveal melanoma is extremely rare in children and also among blacks. Uveal melanomas may be associated with various preexisting conditions, including congenital ocular melanocytosis and dysplastic nevus syndrome. We report the case of a 4-year-old black girl who presented with pronounced proptosis and no light perception secondary to a massive intraocular tumor with extrascleral extension. Biopsy of the tumor confirmed the diagnosis of primary uveal melanoma, and the patient was treated by enucleation and external beam radiation therapy. Although metastatic disease was ruled out at the time, the patient died approximately 3 months later.

Applying an integrated refuge to manage western corn rootworm (Coleoptera: Chrysomelidae): effects on survival, fitness, and selection pressure

The refuge strategy can delay resistance of insect pests to transgenic maize producing toxins from Bacillus thuringiensis (Bt). This is important for the western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), because of its history of adaptation to several management practices. A 2-yr study across four locations was conducted to measure the effects of integrated refuge (i.e., blended refuge) on western corn rootworm survival to adulthood, fitness characteristics, and susceptibility to Bt maize in the subsequent generation. The treatments tested in this study were as follows: a pure stand of Bt maize (event DAS-59122-7, which produces Bt toxins Cry34Ab1/Cry35Ab1), a pure stand of refuge (non-Bt maize), and two variations on an integrated refuge consisting of 94.4% Bt maize and 5.6% non-Bt maize. Within the two integrated refuge treatments, refuge seeds received a neonicotinoid insecticidal seed treatment of either 1.25 mg clothianidin per kernel or 0.25 mg thiamethoxam per kernel. Insects in the pure stand refuge treatment had greater survival to adulthood and earlier emergence than in all other treatments. Although fecundity, longevity, and head capsule width were reduced in treatments containing Bt maize for some site by year combinations, Bt maize did not have a significant effect on these factors when testing data across all sites and years. We found no differences in susceptibility of larval progeny to Bt maize in bioassays using progeny of adults collected from the four treatments.

Outcomes of strabismus surgery for esotropia in children with Down syndrome compared with matched controls

PURPOSE

Strabismus surgery dosages used in children with various neurodevelopmental disorders have been the subject of controversy. Few data have been reported regarding surgical results in individuals with Down syndrome (DS).

METHODS

A retrospective, case-control study was performed in which children with DS and previous bilateral medial rectus recession surgery were matched with similar control patients without DS. Surgical results were compared using a random coefficients model for repeated measurements for each group.

RESULTS

Sixteen patients with DS were matched with 16 control patients. Mean preoperative esotropia was 28.4 prism diopters (PD) in the DS group and 27.9 PD in the control group. No significant difference was found in surgical dosages between the two groups (P = .2402). Median surgical dosage was 4.4 mm in the DS group and 4.5 mm in the control group. Preoperative and 4-month and 24-month postoperative mean angles of esotropia were not different between groups (P = .8050). The 4-month postoperative mean angles of esotropia for the DS and control groups were 3.15 and 2.66 PD, respectively. The 24-month mean angles of esotropia for the DS and control groups were 7.09 and 6.60 PD, respectively.

CONCLUSION

Standard bilateral medial rectus recession surgical dosages need not be modified for individuals with DS.

Complete genome sequence of switchgrass mosaic virus, a member of a proposed new species in the genus Marafivirus

The complete genome sequence of a virus recently detected in switchgrass (Panicum virgatum) was determined and found to be closely related to that of maize rayado fino virus (MRFV), genus Marafivirus, family Tymoviridae. The genomic RNA is 6408 nucleotides long. It contains three predicted open reading frames (ORFs 1-3), encoding proteins of 227 kDa, 43.9 kDa, and 31.5 kDa, compared to two ORFs (1 and 2) for MRFV. The complete genome shares 76 % sequence identity with MRFV. The nucleotide sequence of ORF2 of this virus and the amino acid sequence of its encoded protein are 49 % and 77 % identical, respectively, to those of MRFV. The virus-encoded polyprotein and capsid protein aa sequences are 83 % and 74-80 % identical, respectively, to those of MRFV. Although closely related to MRFV, the amino acid sequence of its capsid protein (CP) forms a clade that is separate from that of MRFV. Based on the International Committee on Taxonomy of Viruses (ICTV) sequence-related criteria for delineation of species within the genus Marafivirus, the virus qualifies as a member of a new species, and the name Switchgrass mosaic virus (SwMV) is proposed.

Relative feeding and development of armyworm on switchgrass and corn, and its potential effects on switchgrass grown for biomass

To help assess the potential for damage by armyworms [Mythimna (Pseudaletia) unipuncta (Haworth) (Lepidoptera: Noctuidae)] to switchgrass (Panicum virgatum L.) and surrounding crops, survival and development were evaluated for larvae reared on leaves of switchgrass, corn (Zea mays L.), and miscanthus (Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize). Additional tests assessed the relationship between leaf position and the concentration of saponins (plant compounds which can provide protection from insect herbivores) and examined the effect of defoliation on switchgrass dry mass. Survival to adulthood was similar when larvae were reared on field-grown leaves of switchgrass and corn. However, lower larval mass (10 d) and delayed development of M. unipuncta (to pupation, adult emergence) suggest switchgrass is an inferior host relative to corn. When fed field-grown miscanthus, no larvae survived 10 d. Few differences were noted between switchgrass and corn grown under controlled (laboratory) conditions, but M. unipuncta survival seemed to decline rapidly when larvae were fed the fourth and fifth leaves of switchgrass. Switchgrass leaf samples collected from different leaf positions and stages of tiller maturity showed up to 10-fold differences in the concentration of the saponin protodioscin, with the greatest concentrations in the fourth and fifth leaves. However, other saponins showed an opposite pattern, indicating the role of protodioscin on insect development should be tested in isolation (e.g., by addition of the purified compound to an artificial diet). Defoliation trials indicated that extremely high M. unipuncta populations may be necessary to cause any significant reduction in switchgrass biomass. Collectively, results suggest M. unipuncta may not present a significant risk to biomass production in switchgrass, but that the spring emergence of switchgrass provides an alternate host for M. unipuncta before colonizing annual food and feed crops.

Relevance of traditional integrated pest management (IPM) strategies for commercial corn producers in a transgenic agroecosystem: a bygone era?

The use of transgenic Bt maize hybrids continues to increase significantly across the Corn Belt of the United States. In 2009, 59% of all maize planted in Illinois was characterized as a "stacked" gene variety. This is a 40% increase since 2006. Stacked hybrids typically express one Cry protein for corn rootworm control and one Cry protein for control of several lepidopteran pests; they also feature herbicide tolerance (to either glyphosate or glufosinate). Slightly more than 50 years has passed since Vernon Stern and his University of California entomology colleagues published (1959) their seminal paper on the integrated control concept, laying the foundation for modern pest management (IPM) programs. To assess the relevance of traditional IPM concepts within a transgenic agroecosystem, commercial maize producers were surveyed at a series of meetings in 2009 and 2010 regarding their perceptions on their use of Bt hybrids and resistance management. Special attention was devoted to two insect pests of corn, the European corn borer and the western corn rootworm. A high percentage of producers who participated in these meetings planted Bt hybrids in 2008 and 2009, 97 and 96.7%, respectively. Refuge compliance in 2008 and 2009, as mandated by the U.S. Environmental Protection Agency (EPA), was 82 and 75.7%, respectively, for those producers surveyed. A large majority of producers (79 and 73.3% in 2009 and 2010, respectively) revealed that they would, or had, used a Bt hybrid for corn rootworm (Diabrotica virgifera virgifera LeConte) or European corn borer (Ostrinia nubilalis Hübner) control even when anticipated densities were low. Currently, the EPA is evaluating the long-term use of seed blends (Bt and non-Bt) as a resistance management strategy. In 2010, a large percentage of producers, 80.4%, indicated they would be willing to use this approach. The current lack of integration of management tactics for insect pests of maize in the U.S. Corn Belt, due primarily to the escalating use of transgenic Bt hybrids, may eventually result in resistance evolution and/or other unforeseen consequences.

First Report of Basal Stem Rot and Foliar Blight Caused by Pythium sylvaticum on Miscanthus sinensis in Illinois

Miscanthus sinensis Anderss., a perennial grass, is native to eastern Asia. It has been widely grown as an ornamental in temperate regions of the world, including the United States, and recently has become an important component of public and private sector bioenergy feedstock Miscanthus selection programs. In August 2008, stem rot and blight was observed on M. sinensis plants in two irregular patches, ~2 to 2.5 × 1 to 1.5 m each in a trial plot that was preceded by corn, at the University of Illinois Energy Farm near Urbana, IL. At the time of the observation, most plants were dead and the wilted tillers had black, soft rotted basal stems. A few plants were stunted and the crowns of the tillers had black-to-brown soft rot. Some tillers' leaves were dead and others had turned light brown. Sample tissue fragments were surface disinfested in 0.5% NaOCl and plated on 1% water agar (WA). After 3 days of incubation in the dark at 23°C, colonies were transferred to corn meal agar (CMA), potato dextrose agar (PDA), or 10% V8 juice agar and incubated at 23°C under continuous white light for up to 2 weeks. Morphological characteristics of the isolates correspond to those originally described for Pythium sylvaticum W.A. Campb. & J.W. Hendrix (1). The mycelia grew and covered the 10-cm-diameter plates within 5 days. On PDA, the culture was a creamy white mycelial mat of coenocytic hyphae. The isolates produced only globose, terminal or intercalary hyphal swellings ranging from 28 to 48 μm in diameter, but no oogonia were produced on any of the three growth media. No zoospores were produced when agar blocks bearing mycelium were flooded with distilled water or 1% soil water. Sequence analysis was performed with the internal transcribed spacer (ITS) region of the rDNA amplified with primer pair ITS1/ITS4 (3) and the mitochondrially encoded cytochrome c oxydase subunit II (cox II) gene using primers FM58/FM66 (2). The resulting 871-bp ITS nucleotide sequence (Accession No. HM991706) was identical among all three isolates analyzed and 99% identical (100% coverage) to ITS sequences of multiple isolates of P. sylvaticum in GenBank. Likewise, the 544-bp cox II sequence (Accession No. HQ454429) was 99% identical (97% coverage) to cox II sequences of multiple isolates of P. sylvaticum. Six pots of M. sinensis seedlings were inoculated by placing two CMA plugs of a 2-week-old culture of isolate F71 at the crown. The control pots were mock inoculated with sterile CMA plugs. The plants were incubated at ~90% relative humidity (RH) and 25°C day and 22°C night for 3 days, and thereafter left on the greenhouse bench at ~65% RH with alternating 9 h of darkness and 15 h of light. Three weeks after inoculation, two of the inoculated seedlings wilted, others were stunted with leaves wilting from the tip downwards and the stems rotting from the crown upward. A thick mat of mycelia was seen on the rotted basal stems. No symptoms were observed in the control. P. sylvaticum was reisolated from both the rotted basal stems and the wilted foliage. To our knowledge, this is the first report of P. sylvaticum on M. sinensis. Infestation of farm soils with P. sylvaticum could limit M. sinensis biomass production significantly by limiting seedling establishment. References: (1) W. A. Campbell and F. F. Hendrix. Mycologia 59:274, 1967. (2) F. M. Martin. Mycologia 92:711, 2000. (3) T. J. White et al. Page 38 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, San Diego, 1990.

Plant-Parasitic Nematodes Are Potential Pathogens of Miscanthus × giganteus and Panicum virgatum Used for Biofuels

A survey of Miscanthus × giganteus and switchgrass plots throughout the midwestern and southeastern United States was conducted to determine the occurrence and distribution of plant-parasitic nematodes associated with these biofuel crops. During 2008, rhizosphere soil samples were collected from 24 Miscanthus × giganteus and 38 switchgrass plots in South Dakota, Iowa, and Illinois. Additional samples were collected from 11 Miscanthus × giganteus and 10 switchgrass plots in Illinois, Kentucky, Georgia, and Tennessee the following year. The 11 dominant genera recovered from the samples were Pratylenchus, Helicotylenchus, Xiphinema, Longidorus, Heterodera, Hoplolaimus, Tylenchorhynchus, Criconemella, Paratrichodorus, Hemicriconemoides, and Paratylenchus. Populations of Helicotylenchus, Xiphinema, and Pratylenchus were common and recorded in 90.5, 83.8, and 91.9% of the soil samples from Miscanthus × giganteus, respectively, and in 91.6, 75, and 83.3% of the soil samples from switchgrass, respectively. Prominence value (PV) (PV = population density × √frequency of occurrence/10) was calculated for the nematodes identified. Helicotylenchus had the highest PV (PV = 384) and was followed by Xiphinema (PV = 152) and Pratylenchus (PV = 72). Several of the nematode species associated with the two biofuels crops were plant parasites. Of these, Pratylenchus penetrans, P. scribneri, P. crenatus, Helicotylenchus pseudorobustus, Hoplolaimus galeatus, X. americanum, and X. rivesi are potentially the most damaging pests to Miscanthus × giganteus and switchgrass. Due to a lack of information, the damaging population thresholds of plant-parasitic nematodes to Miscanthus × giganteus and switchgrass are currently unknown. However, damage threshold value ranges have been reported for other monocotyledon hosts. If these damage threshold value ranges are any indication of the population densities required to impact Miscanthus × giganteus and switchgrass, then every state surveyed has potential for yield losses due to plant-parasitic nematodes. Specifically, Helicotylenchus, Xiphinema, Pratylenchus, Hoplolaimus, Tylenchorhynchus, Criconemella, and Longidorus spp. were all found to have population densities within or above the threshold value ranges reported for other monocotyledon hosts.

Application of sequence-independent amplification (SIA) for the identification of RNA viruses in bioenergy crops

Miscanthus x giganteus, energycane, and Panicum virgatum (switchgrass) are three potential biomass crops being evaluated for commercial cellulosic ethanol production. Viral diseases are potentially significant threats to these crops. Therefore, identification of viruses infecting these bioenergy crops is important for quarantine purposes, virus resistance breeding, and production of virus-free planting materials. The application is described of sequence-independent amplification, for the identification of RNA viruses in bioenergy crops. The method involves virus partial purification from a small amount of infected leaf tissue (miniprep), extraction of viral RNA, amplification of randomly primed cDNAs, cloning, sequencing, and BLAST searches for sequence homology in the GenBank. This method has distinct advantage over other virus characterization techniques in that it does not require reagent specific to target viruses. Using this method, a possible new species was identified in the genus Marafivirus in switchgrass related to Maize rayado fino virus, its closest relative currently in GenBank. Sugarcane mosaic virus (SCMV), genus Potyvirus, was identified in M.xgiganteus, energycane, corn (Zea mays), and switchgrass. Other viruses identified were: Maize dwarf mosaic virus (MDMV), genus Potyvirus, in johnsongrass (Sorghum halepense); Soil borne wheat mosaic virus (SBWMV), genus Furovirus, in wheat (Triticum aestivum); and Bean pod mottle virus (BPMV), genus Comovirus, in soybean (Glycine max). The method was as sensitive as conventional RT-PCR. This is the first report of a Marafivirus infecting switchgrass, and SCMV infecting both energycane and M. x giganteus.

First Report of Pithomyces chartarum Causing a Leaf Blight of Miscanthus × giganteus in Kentucky

Miscanthus × giganteus is a warm-season perennial grass, native to eastern Asia. Brought into the United States as a landscape plant, it is currently being considered as a potential biomass fuel crop. In August 2009, a newly established and a 2-year-old M. × giganteus field research trial near Lexington, KY were found to have 100% incidence of severe leaf blight. Brown, mosaic-like, coalesced necrotic lesions covered leaf blades and sheaths on every stand, ultimately killing some leaves and tillers. The disease was more destructive in the newly established trial where 4- to 5-month-old M. × giganteus tillers were killed. No fruiting bodies were found immediately on diseased leaves. However, surface-disinfested diseased leaf tissue produced a sooty black mass of conidia after 1 week following incubation in a petri dish moisture chamber at 25°C in the dark. Single conidia isolations were made on half-strength potato dextrose agar (HSPDA) amended with 25 mg/liter of rifamycin and incubated at 25°C. Morphological characteristics of the fungus fit those originally described for Pithomyces chartarum (Berk. & Curt.) M.B. Ellis (2). Colonies were fast growing on HSPDA, at first hyaline, then shortly punctiform, grayish black, up to 1-mm diameter, and then became confluent, producing several dark brown multicellular conidia on small peg-like denticles on branched conidiophores. Every detached conidium had a small piece of the denticle attached to its base. The conidia were echinulate, broadly ellipsoidal, pyriform, 18 to 29 × 11 to 18 μm, with three transverse septa, and a longitudinal septum constricted at the transverse septa. The identity of the fungus was confirmed by sequence analysis of the internal transcribed spacers (ITS) region of the nuclear ribosomal DNA. The 615-bp cloned and sequenced amplicon (Accession No. GU195649) was 99% identical to sequences from multiple isolates of Leptosphaerulina chartarum (anamorph Pithomyces chartarum) in the GenBank. Five potted M. × giganteus plants (45 days old) were spray inoculated with an aqueous conidial suspension (2 × 10⁶ conidia/ml) and incubated in one tier of a two-tiered-growth chamber at 86 to 90% relative humidity. Initial incubation was in the dark at 26°C for 48 h, and thereafter at alternating 15 h of light (320 μmol) at 25°C and 9 h of darkness at 23°C. Control plants were sprayed with sterile water and incubated in the second tier of the same growth chamber. A week after inoculation, leaf blight developed on all inoculated plants, but not the controls. P. chartarum was reisolated from infected leaves 2 weeks after inoculation. To our knowledge, this is the first report of P. chartarum causing a disease on Miscanthus (3). The fungus is cosmopolitan, usually saprophytic, but can cause diseases on a wide range of plants as well as produce mycotoxins (3). It has been reported to cause a leaf spot of smooth bromegrass (Bromus inermis) in Nebraska (1) and a leaf blight of wheat (Triticum aestivum) in Hungary (4). The observed disease severity suggests P. chartarum could potentially limit M. × giganteus production as an ethanol feedstock. References: (1) C. Eken et al. Plant Dis. 90:108, 2006. (2) M. B. Ellis. Dematiaceous Hyphomycetes. Commonwealth Mycological Institute, Kew, Surrey, England, 1971. (3) D. F. Farr et al. Fungal Databases, Systematic Mycology and Microbiology Laboratory. Online publication. ARS, USDA, 2010. (4) B. Tóth et al. J. Plant Pathol. 89:405, 2007.

Development and feeding of fall armyworm on Miscanthus x giganteus and switchgrass

Observations of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), larvae infesting plots of Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize prompted laboratory-based tests of survival, development, and feeding preferences on leaf tissue from M. x giganteus and switchgrass, Panicum virgatum L. Survival from hatch to pupation was >70 and 50% for fall armyworms reared on switchgrass and M. x giganteus, respectively, although survival of the S. frugiperda rice strain was significantly greater than the corn strain on both crops. Developmental times from hatch to pupation or adult emergence showed effects of crop and S. frugiperda host strain, but analysis of an interaction revealed developmental times for the rice strain were similar on both crops, whereas corn strain larvae showed delayed development on M. x giganteus relative to switchgrass. Analysis of larval (10 d) and pupal masses showed a similar pattern, with effects of crop and an interaction (at 10 d), but only the mass of corn strain larvae feeding on M. x giganteus was reduced relative to the other crop and strain combinations. In choice tests, neonates of both corn and rice strains showed a strong preference for feeding on young tissues rather than mature leaves of M. x giganteus or switchgrass, but they also clearly favored corn, Zea mays L., leaves over either of the perennial grasses. Results indicate both plants are potential hosts for S. frugiperda, but additional information is needed to understand under which scenarios and to what degree fall armyworms may damage perennial grasses grown for biofuel production.

Development and feeding of fall armyworm on Miscanthus x giganteus and switchgrass

Observations of fall armyworm, Spodoptera frugiperda (J.E. Smith) (Lepidoptera: Noctuidae), larvae infesting plots of Miscanthus x giganteus Greef and Deuter ex Hodkinson and Renvoize prompted laboratory-based tests of survival, development, and feeding preferences on leaf tissue from M. x giganteus and switchgrass, Panicum virgatum L. Survival from hatch to pupation was >70 and 50% for fall armyworms reared on switchgrass and M. x giganteus, respectively, although survival of the S. frugiperda rice strain was significantly greater than the corn strain on both crops. Developmental times from hatch to pupation or adult emergence showed effects of crop and S. frugiperda host strain, but analysis of an interaction revealed developmental times for the rice strain were similar on both crops, whereas corn strain larvae showed delayed development on M. x giganteus relative to switchgrass. Analysis of larval (10 d) and pupal masses showed a similar pattern, with effects of crop and an interaction (at 10 d), but only the mass of corn strain larvae feeding on M. x giganteus was reduced relative to the other crop and strain combinations. In choice tests, neonates of both corn and rice strains showed a strong preference for feeding on young tissues rather than mature leaves of M. x giganteus or switchgrass, but they also clearly favored corn, Zea mays L., leaves over either of the perennial grasses. Results indicate both plants are potential hosts for S. frugiperda, but additional information is needed to understand under which scenarios and to what degree fall armyworms may damage perennial grasses grown for biofuel production.

Adaptation and invasiveness of western corn rootworm: intensifying research on a worsening pest

The western corn rootworm, Diabrotica virgifera virgifera LeConte, is an established insect pest of maize (Zea mays L.) in North America. The rotation of maize with another crop, principally soybeans, Glycine max (L.), was the primary management strategy utilized by North American producers and remained highly effective until the mid-1990s. In 1995, widespread and severe root injury occurred in east-central Illinois and northern Indiana maize fields that had been annually rotated with soybeans on a regular basis for several decades. The failure of this cultural tactic from a pest management perspective was attributed to a behavioral adaptation by a variant western corn rootworm that had lost fidelity to maize for egg laying. In 1992, an infestation of western corn rootworm was found within a small maize field near the Belgrade Airport. By 2007, the presence of this insect pest had been confirmed in 20 European countries. More recent molecular studies have confirmed that at least three separate invasions (until 2004) of western corn rootworms have occurred in Europe, increasing the risk that rotation-resistant western corn rootworms will be introduced into a new continent. Although biological control and use of conventional resistant maize hybrids have not achieved widespread success in the management of western corn rootworms in North America, these tactics are being evaluated in Europe.

A surface-focused biotinylation procedure identifies the Yersinia pestis catalase KatY as a membrane-associated but non-surface-located protein

This study identified major surface proteins of the plague bacterium Yersinia pestis. We applied a novel surface biotinylation method, followed by NeutrAvidin (NA) bead capture, on-bead digestion, and identification by liquid chromatography-tandem mass spectrometry (LC-MS-MS). The use of stachyose during biotinylation focused the reaction to the surface. Coupled with NA pulldown and immunoblot analysis, this method determined whether a protein was accessible to the surface. We applied the method to test the hypothesis that the catalase KatY is a surface protein of the plague bacterium Y. pestis. A rabbit serum recognized the catalase KatY as a major putative outer membrane-associated antigen expressed by Y. pestis cells grown at 37 degrees C. Similar findings by other groups had led to speculations that this protein might be exposed to the surface and might be a candidate for evaluation as a protective antigen for an improved plague vaccine. KatY was obtained only in the total membrane fraction, and stachyose greatly reduced its biotinylation as well as that of the periplasmic maltose binding protein, indicating that KatY is not on the bacterial surface. LC-MS-MS analysis of on-bead digests representing ca. 10(9) cells identified highly abundant species, including KatY, Pal, and OmpA, as well as the lipoprotein Pcp, all of which bound in a biotin-specific manner. Pla, Lpp, and OmpX (Ail) bound to the NA beads in a non-biotin-specific manner. There was no contamination from abundant cytoplasmic proteins. We hypothesize that OmpX and Pcp are highly abundant and likely to be important for the Y. pestis pathogenic process. We speculate that a portion of KatY associates with the outer membrane in intact cells but that it is located on the periplasmic side. Consistent with this idea, it did not protect C57BL/6 mice against bubonic plague.

Population dynamics of a Western corn rootworm (Coleoptera: Chrysomelidae) variant in east central Illinois commercial maize and soybean fields

Three on-farm sites in Iroquois County, IL, each containing an adjacent 16.2-ha commercial production maize, Zea mays L., and soybean, Glycine max (L.) Merr., field, were monitored for western corn rootworm, Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae), adults from June through September 1999-2001. Mean captures of D. v. virgifera adults as measured with Pherocon AM yellow sticky traps were significantly greater in maize than in soybean. Overall mean numbers of D. v. virgifera adults captured with vial traps were significantly greater in soybean than in maize. Emergence cage data revealed that after 50% emergence of D. v. virgifera adults occurred, peak captures of D. v. virgifera adults occurred in maize as measured with vial and Pherocon AM traps. After maize reached the R2 (blister stage, 10-14 d after silking) stage of development and 90% emergence of D. v. virgifera adults had occurred, peak captures of D. v. virgifera adults were observed in soybean by using vial and Pherocon AM traps. Also, after maize reached the R2 stage of development, numbers of females significantly increased in soybean and decreased in maize. Captures of female D. v. virgifera adults frequently exceeded published economic thresholds in soybean, regardless of trap type used. Estimated survival of variant D. v. virgifera (egg to adult) in these commercial rotated maize fields was 10.7 and 9.4% from 1999 to 2000 and from 2000 to 2001, respectively. This compares with nonvariant D. v. virgifera survival estimates in continuous maize production systems in Iowa of 6.7 and 11% from 1983 to 1984 and from 1984 to 1985, respectively.

Ciliary body melanoma with limited nodular extrascleral extension and diffuse iris-angle infiltration treated by whole anterior segment plaque radiotherapy

BACKGROUND

Primary uveal malignant melanoma of the ciliary body associated with nodular extrascleral extension, diffuse iris-angle infiltration, and secondary glaucoma is usually treated by prompt enucleation. We report a patient with ciliary body melanoma associated with nodular extrascleral extension and diffuse infiltration of the iris and angle treated conservatively because the fellow eye was blind.

METHODS

The clinical features and surgical management of a melanoma of the ciliary body with extrascleral extension and diffuse infiltration of the iris and angle are presented. The tumor was treated with focal I-125 plaque radiotherapy followed by supplemental whole anterior segment I-125 plaque radiotherapy.

RESULTS

The patient has been followed for over 2.5 years since the initial plaque radiotherapy and over 1.5 years since the supplemental whole anterior segment radiotherapy. His visual acuity is correctable to 20/40 OD and there is no evidence of metastatic disease. His glaucoma is well controlled following trabeculectomy and tube shunt procedure.

CONCLUSION

Whole anterior segment plaque radiotherapy for ciliary body melanoma with diffuse iris-angle infiltration provided palliative local tumor control without significant local complications through available follow-up.

Planting transgenic insecticidal corn based on economic thresholds: consequences for integrated pest management and insect resistance management

A simulation model of the western corn rootworm, Diabrotica virgifera virgifera LeConte, was used to investigate whether sampling and economic thresholds can improve integrated pest management (IPM) and insect resistance management (IRM) when transgenic insecticidal crops are used for insect pest management. When transgenic corn killed at least 80% of susceptible larvae, the calculated economic threshold increased linearly as the proportion of susceptible beetles surviving the toxin increased. The use of economic thresholds slightly slowed the evolution of resistance to transgenic insecticidal crops. In areas with or without rotation-resistant western corn rootworm phenotypes, the use of sampling and economic thresholds generated similar returns compared with strategies of planting transgenic corn, Zea mays L., every season. Because transgenic crops are extremely effective, farmers may be inclined to plant transgenic crops every season rather than implementing costly and time-consuming sampling protocols.

Effect of four cropping systems on variant western corn rootworm (Coleoptera: Chrysomelidae) adult and egg densities and subsequent larval injury in rotated maize

The cultural practice of rotating corn, Zea mays L., with soybean, Glycine max (L.) Merrill, to manage larval injury by the western corn rootworm, Diabrotica virgifera virgifera LeConte, was used extensively throughout east central Illinois and northern Indiana until the mid-1990s. The effectiveness of this management tactic diminished due to a shift in the ovipositional behavior of the western corn rootworm. The variant western corn rootworm has since spread as far as northwestern Illinois, southern Wisconsin, southern Michigan, and eastern Ohio. The objective of this study was to evaluate the influence of four cropping systems on adult and egg densities of the western corn rootworm and to quantify the level of root injury in rotated corn after each system. The four cropping systems used included: 1) corn; 2) soybean; 3) double-cropped winter wheat, Triticum aestivum L., followed by soybean; and 4) winter wheat. Research trials were conducted near Monmouth (northwestern), DeKalb (northern), and Urbana (east central), IL, during 2003 and 2004. Results indicated variant western corn rootworm adults can be found in all four treatments at each location and consequently no crop was immune to oviposition or root injury by corn rootworm larvae in rotated corn the following season. Adults were found primarily in corn and soybean, whereas egg densities were greatest in corn plots in all three locations in both years of the study. Root injury by larvae was most abundant in corn following corn at all three sites. Of the four systems evaluated, the use of wheat demonstrated the most potential for preventing yield reducing levels of root injury in rotated corn.

Economic analysis of dynamic management strategies utilizing. Transgenic corn for control of western corn rootworm (Coleoptera: Chrysomelidae)

We studied management strategies for western corn rootworm, Diabrotica virgifera virgifera LeConte, using transgenic corn, Zea mays L., from both a biological and an economic perspective. In areas with and without populations adapted to a 2-yr rotation of corn and soybean (rotation-resistant), the standard management strategy was to plant 80% of a cornfield (rotated and continuous) to a transgenic cultivar each year. In each area, we also studied dynamic management strategies where the proportion of transgenic corn increased over time in a region. We also analyzed management strategies for a single field that is the first to adopt transgenic corn within a larger unmanaged region. In all areas, increasing the expression of the toxin in the plant increased economic returns. In areas without rotation-resistance, planting 80% transgenic corn in the continuous cornfield each year generated the greatest returns with a medium toxin dose or greater. In areas with alleles for rotation-resistance at low initial levels, a 2-yr rotation of nontransgenic corn and soybean, Glycine max (L.) Merr., may be the most economical strategy if resistance to crop rotation is recessive. If resistance to crop rotation is additive or dominant, planting transgenic corn in the rotated cornfield was the most effective strategy. In areas where rotation-resistance is already a severe problem, planting transgenic corn in the rotated cornfield each year was always the most economical strategy. In some cases the strategies that increased the proportion of transgenic corn in the region over time increased returns compared with the standard strategies. With these strategies the evolution of resistance to crop rotation occurred more rapidly but resistance to transgenic corn was delayed compared with the standard management strategy. In areas not managed by a regional norm, increasing the proportion of transgenic corn and increasing toxin dose in the managed field generally increased returns. In a sensitivity analysis, among the parameters investigated, only density-dependent survival affected the results.

Ovarian development and ovipositional preference of the western corn rootworm (Coleoptera: Chrysomelidae) variant in east central Illinois

The rotation of maize, Zea mays L., and soybean, Glycine max (L.) Merr., has been the traditional cultural tactic to manage the western corn rootworm, Diabrotica virgifera virgifera LeConte, in the Corn Belt. The reduced effectiveness of this rotation as a pest management tool in east central Illinois, northern Indiana, and southern Michigan can be explained by the shift in the ovipositional behavior of the new variant of western corn rootworm. The objective of this study was to evaluate the influence of maize, soybean, oat, Avena sativa L., stubble, and alfalfa, Medicago sativa L., on the ovarian development and ovipositional preferences of the variant western corn rootworm. Field research was conducted near Urbana, IL, during 1998-2000. Gravid females were present throughout the season in all crops, and due to the prolonged period in which western corn rootworm females can lay eggs, none of the crops were immune from oviposition. Results indicated that the western corn rootworm variant oviposits in maize, soybean, oat stubble, and alfalfa In 1998 and 1999, maize was the preferred oviposition site among crops; however, in 2000, maize, soybean, and oat stubble treatments had similar densities of western corn rootworm eggs. Lack of oviposition preference of the western corn rootworm variant demonstrated in this experiment represents a reasonable explanation of why the effectiveness of the rotation strategy to control western corn rootworm has diminished.

Economics versus alleles: balancing integrated pest management and insect resistance management for rotation-resistant western corn rootworm (Coleoptera: Chrysomelidae)

Western corn rootworm, Diabrotica virgifera virgifera LeConte, has overcome crop rotation in several areas of the central United States. We expanded a simple model of adult behavior and population genetics to explain how rotation resistance may have developed and to study ways to manage the western corn rootworm in a landscape of corn, soybean, and winter wheat where evolution of resistance may occur. We modeled six alternative management strategies over a 15-yr time horizon, as well as a strategy involving a 2-yr rotation of corn and soybean in 85% of the landscape, to investigate their effectiveness from both a biological and economic perspective. Generally, resistance to crop rotation evolves in fewer than 15 yr, and the rate of evolution increases as the level of rotated landscape (selection pressure) increases. When resistance is recessive, all six alternative strategies were effective at preventing evolution of rotation resistance. The two most successful strategies were the use of transgenic rotated corn in a 2-yr rotation and a 3-yr rotation of corn, soybean, and wheat with unattractive wheat (for oviposition) preceding corn. Results were most sensitive to increases in the initial allele frequency and modifications of the density-dependent survival function. Economically, three alternative strategies were robust solutions to the problem, if technology fees were not too high. Repellant soybean, attractive rotated corn, and transgenic rotated corn, all in 2-yr rotations, were economically valuable approaches. However, even the currently common 2-yr rotation was economical when resistance was recessive and the actual costs of resistance would not be paid until far in the future.

Captures of western corn rootworm (Coleoptera: Chrysomelidae) adults with Pherocon AM and vial traps in four crops in east central Illinois

It is hypothesized that the long-term rotation of maize (Zea mays L.) and soybean (Glycine max L.) in east central Illinois has caused a significant change in the ovipositional behavior of the western corn rootworm, Diabrotica virgifera virgifera LeConte. Since the mid 1990s in east central Illinois, western corn rootworm adults have been observed feeding on soybean foliage and also now use soybean fields as egg laying sites. This behavioral adaptation has greatly decreased the effectiveness of rotation as a pest management tactic. By using Pherocon AM and vial traps, we evaluated the influence of maize, soybean, oat stubble (Avena sativa L.), and alfalfa (Medicago sativa L.) on male and female adult western corn rootworm densities from April 1998 through September 2000 near Urbana, IL. Our results indicated that western corn rootworm adults are common inhabitants of maize, soybean, oat stubble, and alfalfa. Trapping efforts with both Pherocon AM (attractive) and vial traps (passive) revealed that initial densities of both male and female western corn rootworm adults were greater in maize. Soon after emergence, densities of females began to decline within maize and increase in other crops (soybean, oat stubble, and alfalfa). Results from this experiment support the hypothesis that variant western corn rootworm females in east central Illinois are colonizing crops other than maize at densities of potential economic importance. Those producers who choose to rotate maize with soybean or alfalfa may remain at risk to economic larval injury to maize roots. Potentially, oat stubble also may support levels of western corn rootworm females resulting in sufficient oviposition to cause economic losses to rotated maize the following season.

Modeling the dynamics of adaptation to transgenic corn by western corn rootworm (Coleoptera: Chrysomelidae)

A simulation model of the population dynamics and genetics of the western corn rootworm, Diabrotica virgifera virgifera LeConte, was created for a landscape of corn, soybean, and other crops. Although the model was created to study a 2-locus problem for beetles having genes for resistance to both crop rotation and transgenic corn, during this first phase of the project, the model was simulated to evaluate only resistance management plans for transgenic corn. Allele expression in the rootworm and toxin dose in the corn plant were the two most important factors affecting resistance development. A dominant resistance allele allowed quick evolution of resistance to transgenic corn, whereas a recessive allele delayed resistance >99 yr. With high dosages of toxin and additive expression, the time required to reach 3% resistance allele frequency ranged from 13 to >99 yr. With additive expression, lower dosages permitted the resistant allele frequency to reach 3% in 2-9 yr with refuges occupying 5-30% of the land. The results were sensitive to delays in emergence by susceptible adults and configuration of the refuge (row strips versus blocks).

Predicting western corn rootworm (Coleoptera: Chrysomelidae) larval injury to rotated corn with Pherocon AM traps in soybeans

Crop rotation for portions of east central Illinois and northern Indiana no longer adequately protects corn (Zea mays L.) roots from western corn rootworm, Diabrotica virgifera virgifera LeConte. Seventeen growers in east central Illinois monitored western corn rootworm adults in soybean (Glycine max L.) fields with unbaited Pherocon AM traps during 1996 and 1997. In the following years (1997 and 1998), growers left untreated strips (no insecticide applied) when these fields were planted with corn. Damage to rotated corn by rootworms was more severe in untreated than in treated strips of rotated corn, ranging from minor root scarring to a full node of roots pruned. Densities of western corn rootworms in soybean fields from 1996 were significantly correlated with root injury to rotated corn the following season. Adult densities from 1997 were not significantly correlated with root injury in 1998, due to heavy precipitation throughout the spring of 1998 and extensive larval mortality. Twenty-eight additional growers volunteered in 1998 to monitor rootworm adults in soybean fields with Pherocon AM traps based on recommendations that resulted from our research efforts in 1996 and 1997. In 1999, these 28 fields were rotated to corn, and rootworm larval injury was measured in untreated strips. Based on 1996-1997 and 1998-1999 data, a regression analysis revealed that 27% of the variation in root injury to rotated corn could be explained by adult density in soybeans the previous season. We propose a sampling plan for soybean fields and a threshold for predicting western corn rootworm larval injury to rotated corn.

Temporal-spatial distribution of hepatocyte nuclear factor-3beta in developing human lung and other foregut derivatives

We assessed the temporal-spatial distribution of hepatocyte nuclear factor-3beta (HNF-3beta) in developing human lung and other foregut derivatives. Tissue from 31 fetuses (10-40 weeks) and 24 infants with hyaline membrane disease (HMD) or bronchopulmonary dysplasia (BPD) (2 days to 7 months) was studied. HNF-3beta was detected in nuclei of epithelial cells of trachea and of conducting and terminal airways at 10 weeks. Thereafter, epithelial nuclei were immunolabeled more widely in peripheral than proximal airways. HNF-3beta was confined to bronchiolo-alveolar portals and Type II cells in nonfetal lung. In infants with BPD, HNF-3beta was expressed abundantly in regenerating epithelial cells at the periphery of lung lobules. HNF-3beta was also detected in fetal esophagus, pancreas, duodenum, stomach, and gallbladder, suggesting that it is a marker for progenitor cells in foregut derivatives. The pattern of expression of HNF-3beta in the lung was similar to that of thyroid transcription factor-1 (TTF-1) at all ages. The temporal-spatial patterns of HNF-3beta and TTF-1 in the developing and regenerating lung are consistent with their proposed role in epithelial cell differentiation, regeneration, and surfactant protein gene expression. (J Histochem Cytochem 46:955-962, 1998)

Immunogold EM localization of neurochemicals in human pulmonary neuroendocrine cells

Antibodies against the pulmonary neuroendocrine cell peptides gastrin-releasing peptide (bombesin), calcitonin and calcitonin gene-related peptide (CGRP) have been labeled with colloidal gold spheres for immunocytochemical localization in human fetal and newborn lung tissue. In general, the presence and amount of immunolabeling increased with increasing gestational age, with only calcitonin appearing late in fetal life. The largest percentage of neuroepithelial body (NEB) cells labeled and the largest number of labeled dense core vesicles (DCV) were in infants with chronic lung disease (bronchopulmonary dysplasia). Serial ribbons allowed identification of more than one peptide in a single NEB cell. The use of two antibodies labeled with colloidal gold spheres of different sizes allowed the identification of two peptides in the same DCV. Quantification of relative amounts of labeled peptides was not possible, as the peptide labeling with the larger size gold sphere was consistently underestimated. Colocalization to the same DCV has been shown in humans for bombesin and calcitonin, calcitonin and CGRP, bombesin and CGRP and, by others for cholecystokinin (CCK) and serotonin. Colocalization of two or more peptides or an amine to a single DCV within the same cell implies simultaneous discharge by exocytosis. The action of the two (or more) substances might be in concert, perhaps with one acting in a paracrine fashion, and the second in an autocrine fashion. In this case, the second peptide or amine might have a regulatory function in the parent cell, influencing DCV storage or rate of release.

Immunogold EM localization of neurochemicals in human pulmonary neuroendocrine cells

Antibodies against the pulmonary neuroendocrine cell peptides gastrin-releasing peptide (bombesin), calcitonin and calcitonin gene-related peptide (CGRP) have been labeled with colloidal gold spheres for immunocytochemical localization in human fetal and newborn lung tissue. In general, the presence and amount of immunolabeling increased with increasing gestational age, with only calcitonin appearing late in fetal life. The largest percentage of neuroepithelial body (NEB) cells labeled and the largest number of labeled dense core vesicles (DCV) were in infants with chronic lung disease (bronchopulmonary dysplasia). Serial ribbons allowed identification of more than one peptide in a single NEB cell. The use of two antibodies labeled with colloidal gold spheres of different sizes allowed the identification of two peptides in the same DCV. Quantification of relative amounts of labeled peptides was not possible, as the peptide labeling with the larger size gold sphere was consistently underestimated. Colocalization to the same DCV has been shown in humans for bombesin and calcitonin, calcitonin and CGRP, bombesin and CGRP and, by others for cholecystokinin (CCK) and serotonin. Colocalization of two or more peptides or an amine to a single DCV within the same cell implies simultaneous discharge by exocytosis. The action of the two (or more) substances might be in concert, perhaps with one acting in a paracrine fashion, and the second in an autocrine fashion. In this case, the second peptide or amine might have a regulatory function in the parent cell, influencing DCV storage or rate of release.

Ontogeny of Clara cell-specific protein and its mRNA: their association with neuroepithelial bodies in human fetal lung and in bronchopulmonary dysplasia

Clara cell-specific 10-KD protein (CCSP) is an abundant product of nonciliated bronchiolar epithelial (Clara) cells in the lung. We have determined the temporal-spatial distribution of CCSP and its mRNA in developing human lung and in neonatal lung disease, using immunohistochemistry and in situ hybridization. CCSP immunoreactivity was found in nonciliated bronchiolar epithelial cells from 12 weeks of gestation onward. Tracheal and bronchial epithelia showed positive immunoreactivity at each gestational week after 15 weeks and 14 weeks, respectively. CCSP mRNA was seen in the bronchial and bronchiolar epithelia from 16 weeks onward and was detected in the trachea from 19 through 23 weeks of gestation. CCSP immunoreactivity and mRNA were present in nonciliated single cells of bronchial and bronchiolar epithelia in fetuses and in infants with and without lung disease. CCSP- and CCSP mRNA-containing epithelial cells also formed dusters around neuroepithelial bodies (NEBs), especially at airway branch points, suggesting that NEBs and Clara cells might interact during development and during pulmonary regeneration. Because of evidence of overlapping of some but not all cells expressing CCSP, SP-A, and pro-SP-B during lung development, a common cell lineage is proposed, with subsequent divergence of phenotypes.

Expression of thyroid transcription factor-1(TTF-1) in fetal and neonatal human lung

We assessed the immunohistochemical localization of thyroid transcription factor-1 (TTF-1) in the lungs of 24 human fetuses (11-23 weeks), three infants without pulmonary pathology (36-42 weeks), and 24 infants (2 days-6.5 months) with hyaline membrane disease (HMD) or bronchopulmonary dysplasia (BPD). TTF-1 was detected in fetal lung epithelial cell nuclei by 11 weeks' gestation. Budding tips of terminal airways had prominently labeled nuclei. By 17 weeks, labeling was present in scattered nonciliated columnar and cuboidal cells. Throughout gestation, TTF-1 nuclear staining was prominent in airways abutting pleural, peribronchial, or perivascular connective tissue, being less prominent in centers of lobules. By 23 weeks, many cells in cuboidal but not columnar cell-lined airways had labeled nuclei. At term, TTF-1 was detected primarily in Type II epithelial cells. In HMD with alveolar hemorrhage, edema, or airway collapse, little or no TTF-1 was present except in open terminal airways. In BDP lungs, TTF-1 was absent in areas of alveolar collapse or infection, being present in regenerating open airways. The temporal-spatial distribution of TTF-1, in general, follows patterns of distribution of surfactant protein-B in developing and pathological lungs, consistent with its role in the regulation of epithelial cell gene expression in the lung.

Respiratory syncytial virus infection enhances the response to laryngeal chemostimulation and inhibits arousal from sleep in young lambs

To evaluate the effect of respiratory syncytial virus (RSV) infection on the response to laryngeal chemostimulation (LCS) with water, five lambs were inoculated with human RSV and three lambs were given control media at an age of 3-5 days. During RSV infection, LCS resulted in increased inhibition of minute ventilation and delayed recovery of regular breathing. Sleep further increased the response, and arousal was less likely to occur in active sleep. Two of the five infected lambs needed resuscitation after LCS when arousal was absent. Histological studies showed bronchiolitis and pneumonitis. Laryngeal tastebud morphology was unchanged at 8 days after inoculation. However, infected lambs had disrupted tastebuds 4-6 weeks after infection. Failure to arouse and to terminate reflex apnea may play a role in the pathogenesis of the sudden infant death syndrome associated with respiratory tract infection.

Temporal-spatial distribution of SP-B and SP-C proteins and mRNAs in developing respiratory epithelium of human lung

We determined the temporal and spatial distribution of surfactant protein B (pro-SP-B) and C (pro-SP-C) mRNAs and proteins by immunohistochemistry and in situ hybridization in fetal, neonatal, and adult human lung. Pro-SP-B and SP-B mRNA were detected in bronchi and bronchioles by 15 weeks' gestation. After 25 weeks, pro-SP-B, active SP-B peptide, and SP-B mRNA were co-localized in bronchiolo-alveolar portal cells and in Type II epithelial cells. In adult lung, pro-SP-B and SP-B mRNA were detected primarily in non-ciliated bronchiolar epithelial cells and in Type II cells in the alveolus. Pro-SP-C and SP-C mRNA were detected in cells lining terminal airways from 15 weeks' gestation and thereafter. After 25 weeks, SP-C mRNA and precursor protein were detected in epithelial cells of the bronchiolo-alveolar portals and in Type II cells, where expression increased with advancing gestational age. Distinct cellular patterns of staining for pro-SP-B compared with SP-B active peptide support the concept that its proteolytic processing or cellular routing may be influenced by cell type and/or cell differentiation. SP-B and SP-C are expressed primarily in distal conducting and terminal airway epithelium of human fetal lung well in advance of surfactant lipid synthesis or physiologic requirements to produce pulmonary surfactant at the time of birth.

Developmental expression of SP-A and SP-A mRNA in the proximal and distal respiratory epithelium in the human fetus and newborn

We used immunolocalization and in situ hybridization to determine the distribution of SP-A and SP-A mRNA in lungs of human fetuses and normal newborn infants. Early in the second fetal trimester a few immunostained cells were observed in tracheal epithelium, often in mucosal folds near the origin of submucosal gland ducts. Non-mucous tracheal gland cells were immunostained for SP-A as they became differentiated. Expression of SP-A mRNA was similar to that of immunolocalization in the second trimester. Immunostained cells and SP-A mRNA also appeared about the same time in gestation in isolated cells of bronchial epithelium and glands. SP-A mRNA was seen in bronchiolar cells and pre-Type II cells lining terminal airways of fetuses at 19-20 weeks of gestation. Only in liveborn infants did cells of bronchioloalveolar portals and mature Type II cells contain SP-A mRNA or immunostain for SP-A. In postnatal infants, luminal material was also stained for SP-A. Although some alveolar macrophages contained immunoreactive material, SP-A mRNA was never detected. The abundance of SP-A in tracheal and bronchial glands and epithelium of conducting airways supports the importance of non-surfactant-associated functions for SP-A and may be related to a role in host defense.

Colocalization of peptide hormones in neuroendocrine cells of human fetal and newborn lungs: an electron microscopic study

This study investigated the colocalization of the peptide hormones bombesin or calcitonin with calcitonin gene related peptide (CGRP) in neuroendocrine cells (NE) in the lungs of human fetuses of varying gestational ages and in the lungs of newborn infants who died with acute or chronic lung disease in the first weeks or months after birth. Double immunolabeling of dense core granules for these peptides was also studied in this same patient population. On-grid double gold immunolabeling was carried out on 29 subjects using anti-bombesin and anti-CGRP and on 22 subjects using anti-calcitonin and anti-CGRP as primary antibodies, the secondary antibodies being labeled with different-size gold spheres. Colocalization of both bombesin and calcitonin with CGRP was demonstrated, not only in the same NE cell, but also on the same dense core granule. Colocalization was rarely found in normal fetuses, and most frequently found in newborn infants with acute lung disease, usually hyaline membrane disease (HMD), or with the development of chronic lung disease in the first weeks or months after birth. Double labeling of the same dense core granules might imply action of peptides in concert, or perhaps one peptide acting in a paracrine role (e.g., on bronchial or bronchiolar smooth muscle) and the second peptide acting in an autocrine fashion on the parent cell (e.g., in the regulation of granule production or release).

The ontogeny and distribution of surfactant protein B in human fetuses and newborns

The distribution of immunoreactive surfactant-associated protein B (IR-SP-B) was studied immunohistochemically in 120 subjects from 10 weeks of gestation to 7 postnatal months with a polyclonal antibody against human SP-B. Electron microscopy (EM) was done in 72 subjects to document the presence of Type II cells containing lamellar bodies. Fetuses of less than 18 weeks' gestation showed no immunostaining. Beginning at 18 weeks, non-mucous cells of tracheal glands immunostained in a few instances. Fetuses of 19 through 23 weeks showed progressive immunostaining of cells lining terminal airways. Infants 26-40 weeks who died with or without pulmonary pathology showed immunostaining of Type II cells and bronchioloalveolar (BA) portal cells of the respiratory bronchioles. In infants with hyaline membrane disease (HMD) who died less than 12 days after birth, occasional tracheal gland cells, BA portal cells, and mature and relining Type II cells immunostained. In bronchopulmonary dysplasia (BPD), BA portal cells, relining Type II cells, macrophages, and luminal material immunostained. Occasional tracheal and bronchial gland cells and Clara cells immunostained. The appearance of IR-SP-B at mid-gestation correlated with differentiation of Type II cells. There was good correlation of immunostaining with the presence of lamellar bodies on EM. Accelerated maturation of the lung was often associated with premature rupture of membranes (PROM).

Human surfactant protein-A contains blood group A antigenic determinants

A major blood group antigenic epitope was identified on human pulmonary surfactant protein A (SP-A). MAb and polyclonal antibodies generated against purified human SP-A aggregated blood group A human erythrocytes and immunostained epithelial cells in a variety of human tissues, consistent with the tissue distribution of major blood group antigens. SP-A MAb (MAb-8) agglutinated red cells and immunostained tissues from A or AB blood groups, but did not react with cells or tissues from O or B individuals. MAb-8 immunostaining of tissue from blood group A individuals was ablated by incubation with blood group A red cells. MAb and polyclonal antibodies directed against A blood group antigens reacted strongly with purified SP-A obtained from a blood group A individual with alveolar proteinosis. MAb and polyclonal antibodies specific for B blood group antigen failed to react with SP-A from this patient or from patients who were in blood group B. Reactivity of anti-blood group MAb was lost after treatment of SP-A with endoglycosidase-F, demonstrating its reactivity with an epitope dependent on the asparagine-linked oligosaccharide at asparagine 187. Reactivity of MAb-8 with SP-A persisted after endoglycosidase-F treatment, but was lost after digestion with collagenase as assessed by Western blot after SDS-PAGE. Reactivity of MAb to SP-A was sensitive to beta-elimination, supporting the presence of another blood group antigenic site distinct from the epitope dependent on the asparagine-linked carbohydrate. The finding that the SP-A molecule contains a major blood group epitope has implication for the clinical use of surfactant replacement preparations and diagnostic reagents based on this protein.

Lipocortin-1 immunoreactivity in the human pituitary gland

We evaluated the distribution of lipocortin-1 immunoreactivity in 118 immature or mature human hypophyses using the peroxidase-antiperoxidase (PAP) technique with a polyclonal rabbit antiserum against lipocortin-1. Serial sections were evaluated for five pituitary hormones and S-100 protein immunoreactivity to compare their distributions with that of lipocortin-1. Scattered or moderate numbers of cells exhibited lipocortin-1 immunoreactivity in the pars distalis of 89 subjects ranging in age from 27 weeks' gestation to 83 years. Seven immature and seven aged specimens exhibited no immunostaining, while 15 specimens from older individuals exhibited only rare immunostaining. Immunostaining did not appear to co-localize selectively with any specific pituitary hormone, although the distribution of immunoreactivity did overlap that of some corticotrophs and was seen in elongated processes of S-100-containing folliculostellate cells. Lipocortin-1 was also found in epithelial cells lining colloid cysts of the residual pars intermedia in 115 of 118 pituitaries ranging in age from 23 weeks' gestation to 83 years. In many intermediate lobe cysts, lipocortin-1 exhibited a pattern of immunoreactivity that partially overlapped the distribution of S-100 protein immunostaining, although the pattern was not identical. Pre-absorption of anti-lipocortin-1 antiserum with lipocortin-1-coupled Sepharose-4B immunoreactivity resulted in loss of immunoreactivity in both lobes. No lipocortin-1 immunoreactivity was seen in the neurohypophysis.