Outcome of Primary Monocanalicular Stent Placement in Pediatric Down Syndrome Patients with Congenital Nasolacrimal Obstruction

PURPOSE

Congenital Nasolacrimal duct obstruction (CNLDO) is a relatively common problem in children with Down syndrome (DS). Probing and irrigation (PI) with monocanalicular stent intubation may be less successful than in non-DS patients, thus raising some concerns regarding the preferred treatment in this population. We aimed to analyze the surgical outcome of PI along with monocanalicular stent intubation in children with DS compared with non-DS patients.

METHODS

Retrospective cohort study. Thirty-five eyes of 19 children with DS and 1,472 eyes of 1,001 children without DS underwent PI-monocanalicular stent intubation as a primary treatment for CNLDO. All patients were operated on by a single surgeon at the Children's Hospital of Philadelphia between 2009 and 2020. The main outcome measure was a surgical success, defined as the resolution of symptoms after surgery.

RESULTS

A total of 1,020 patients were included, 48% females; mean age of 1.9 ± 1.4 years. The mean follow-up time was 35.0 months. The DS patients group consisted of 19 patients. Higher rates of right nasolacrimal duct obstruction and bilateral obstructions were observed in the DS group (100% vs. 73.2%; p = 0.006, and 84.2% vs. 46.8%; p = 0.001, respectively). Patients with DS had a lower success rate (57.1% vs. 92.4%; p < 0 .0001). The median time to failure was 3.1 months in the DS group, and 5.2 months in the group of patients without DS. The hazard ratio comparing DS to the no-DS outcome was 6.6 (95% CI: 3.2-13.7; p < 0.001).

CONCLUSIONS

CNLDO in DS is more likely to be bilateral and less likely to resolve after primary monocanalicular stent placement.

Clinical Impact of Contouring Variability for Prostate Cancer Tumor Boost

PURPOSE/OBJECTIVE(S)

In the FLAME randomized phase III trial, adding a focal radiotherapy (RT) boost to tumors visible on MRI improved prostate cancer disease-free survival, local control, and regional/distant metastasis-free survival without increasing toxicity. In a prospective study (ReIGNITE RT Boost), we found substantial variability in radiation oncologists' attempts to contour prostate cancer tumors on MRI. Participants' accuracy and reliability improved when they used a quantitative MRI biomarker for cancer called the restriction spectrum imaging restriction score (RSIrs). Here, we measure the impact of radiation oncologists' tumor contour attempts on RT plans and predicted probability of biochemical failure.

MATERIALS/METHODS

A total of 44 radiation oncologists (participants) from multiple institutions contoured prostate tumors on 30 patient cases, some with only conventional MRI and some with conventional MRI plus RSIrs maps. We developed a knowledge-based planning automated algorithm to generate RT plans with focal tumor boost per the FLAME trial protocol: 77 Gy in 35 fractions to prostate and integrated boost up to 95 Gy to the focal target, provided no normal tissue constraints were violated. We applied this algorithm to each participant's tumor contour and compared dosimetric parameters to those achieved when using the expert-defined tumor (consensus of two radiologists and a radiation oncologist). The primary metric was dose covering 98% of the expert-defined tumor (D98%), which was associated with probability of biochemical failure in a model published with the FLAME trial.

RESULTS

In this preliminary analysis, 42 target volumes were analyzed from 20 participants and two patient cases: case 1 was contoured with conventional MRI alone and case 2 with RSIrs. All plans had adequate coverage of the prostate and met all key normal tissue constraints. For case 1 (without RSIrs), the expert's D98% was 87.1 Gy. By comparison, median D98% for participants was 82.2 Gy (IQR 77.8 - 84.6 Gy). Per the FLAME trial model, the predicted probability of biochemical failure at 7 years is 6% for the expert, but participants' plans yielded a median failure probability of 11% (IQR 18 - 9%). For case 2 (with RSIrs), the expert's D98% was 82.8 Gy, while median D98% for participants was 80.6 Gy (IQR 80.0 - 81.0 Gy). Predicted probability of biochemical failure is 12% for the expert-defined target and median 13% (IQR 14 - 13%) for participants.

CONCLUSION

Variability in radiation oncologists' prostate tumor contours can lead to clinically meaningful changes to focal RT boost plans. The probability of biochemical failure for one patient case increased from 6% to a median of 11% when using conventional MRI alone. Use of RSIrs may mitigate this problem by increasing the accuracy and reliability of radiation oncologists' tumor contours.

Outcomes of resident physician-performed cataract surgery in a diverse veterans affairs health system population

Purpose

To evaluate visual acuity (VA) outcomes and complications from resident physician-performed cataract surgery in a diverse Veterans Affairs Hospital population.

Methods

A retrospective chart review was conducted for patients who underwent cataract surgery performed by resident physicians from 01/01/2013 to 12/31/2015 at the Veterans Affairs Medical Center. Intraoperative and postoperative clinical information, best-corrected VA (BCVA) (1 day, months 1, 2-3, and 6), and surgery complications were extracted. Univariable and multivariable linear regression models were performed for risk factors of BCVA change.

Results

This study included 1183 patients, with mean (SD) age of 70.8 (9.3) years. 1154 (97.5%) were males, 493 (41.7%) African-American, and 681 (57.6%) Caucasian. The mean (SD) VA in logMAR was 0.69 (0.74) at baseline, improved to 0.19 (0.36) at 1 month, 0.16 (0.34) at 2-3 months, and 0.14 (0.36) at 6 months. 1080 (91.3%) patients experienced VA improvement from baseline and 1023 (86.5%) patients achieved at least 20/40 BCVA at 1 month. There were 86 (7.3%) complications, most commonly including 47 (4.0%) posterior capsular tears and 64 (5.4%) vitreous loss. In multivariable analysis, younger age (P < 0.0001), worse baseline VA (P < 0.0001), and absence of iris prolapse (P < 0.001) were significantly associated with greater improvement in VA at 1 month.

Conclusion

In a diverse VAMC, resident-performed cataract surgeries achieved significant improvement in VA with a cumulative complication rate lower than previously reported. Resident physician education may benefit from specific focus on prevention of iris prolapse and better incision construction during surgery as these intraoperative events often led to delayed stabilization of visual outcome beyond 1 month.

Glucagon-like peptide 1 receptor agonist use is associated with reduced risk for glaucoma

BACKGROUND/AIMS

Glucagon-like peptide-1 receptor (GLP-1R) agonists regulate blood glucose and are commonly used to treat type 2 diabetes mellitus. Recent work showed that treatment with the GLP-1R agonist NLY01 decreased retinal neuroinflammation and glial activation to rescue retinal ganglion cells in a mouse model of glaucoma. In this study, we used an insurance claims database (Clinformatics Data Mart) to examine whether GLP-1R agonist exposure impacts glaucoma risk.

METHODS

A retrospective cohort of patients who initiated a new GLP-1R agonist was 1:3 age, gender, race, classes of active diabetes medications and year of index date matched to patients who initiated a different class of oral diabetic medication. Inverse probability of treatment weighting (IPTW) was used within a multivariable Cox proportional hazard regression model to test the association between GLP-1R agonist exposure and a new diagnosis of primary open-angle glaucoma, glaucoma suspect or low-tension glaucoma.

RESULTS

Cohorts were comprised of 1961 new users of GLP-1R agonists matched to 4371 unexposed controls. After IPTW, all variables were balanced (standard mean deviation <|0.1|) between cohorts. Ten (0.51%) new diagnoses of glaucoma were present in the GLP-1R agonist cohort compared with 58 (1.33%) in the unexposed controls. After adjustment, GLP-1R exposure conferred a reduced hazard of 0.56 (95% CI: 0.36 to 0.89, p=0.01), suggesting that GLP-1R agonists decrease the risk for glaucoma.

CONCLUSIONS

GLP-1R agonist use was associated with a statistically significant hazard reduction for a new diagnosis of glaucoma. Our findings support further investigations into the use of GLP-1R agonists in glaucoma prevention.

Effect of Autologous Platelet-Rich Plasma Drops in the Treatment of Ocular Surface Disease

Purpose

Platelet rich plasma (PRP) is an autologous preparation that concentrates platelets in a small volume of plasma. The purpose of this study was to determine if PRP eye drops improved the symptoms and signs of ocular surface disease.

Patients and Methods

A retrospective case series was conducted of patients who were prescribed PRP eye drops. Subjects were excluded if they did not have follow-up, underwent intraocular surgery prior to follow-up, received nerve growth factor treatments, or did not have a baseline examination with photography. Symptoms were assessed using the Ocular Surface Disease Index (OSDI). Patients also underwent a slit lamp exam, ocular surface staining with fluorescein and lissamine green, and Schirmer testing.

Results

The charts of 47 patients treated with PRP drops for ocular surface disease were reviewed. Sixty-four eyes of 32 patients were included in the study who had photographs of lissamine green staining taken at baseline and at follow-up. Thirteen patients (28%) had ocular graft-versus-host disease, 16 patients (34%) had Sjögren's syndrome, and 4 patients (8.5%) had rheumatoid arthritis. There was a statistically significant decrease in OSDI score from baseline to follow-up (39.5 vs 30.8 points, p = 0.02). Among the 64 eyes included, 9 (14%) had an improvement in conjunctival lissamine green staining, while 6 (9%) had an increase in staining at follow-up. Among the 20 eyes with Schirmer testing, there was a borderline significant increase in score from baseline to follow-up (5.9 vs 9.7, p = 0.06). Among the 44 eyes that had corneal fluorescein staining (CFS) reported, 8 (18.2%) had decreased staining and 2 (4.5%) had increased staining at follow-up.

Conclusion

Treatment with PRP drops was associated with a significant improvement in symptoms in patients with ocular surface disease. Future larger prospective studies are needed to further evaluate the efficacy of PRP drops for treating ocular surface disease.

Recent Practice Patterns in Acute Retinal Artery Occlusions in the United States

PURPOSE

To determine how to practice patterns for work-up of incident retinal artery occlusion (RAO) compare to the American Academy of Ophthalmology (AAO) guidelines.

METHODS

In this cohort study, patients receiving a new diagnosis of RAO, either central (CRAO) or branch (BRAO), were identified between 2002 and 2020 from a large US medical claims database. Claims were reviewed for diagnostic tests specified by the AAO as essential components of an RAO work-up including carotid ultrasound, echocardiogram, magnetic resonance imaging (MRI) and emergency department (ED) referral. Outcomes included rates of and time to completion of work-up.

RESULTS

18697 new outpatient diagnoses of RAO (11348 BRAO, 7349 CRAO) were analyzed. 15.9% and 30.4% of patients received carotid ultrasounds within 7 and 30 days, respectively. 9.4% and 21.1% of patients received echocardiograms within 7 and 30 days, respectively. 4.9% and 8.1% of patients received a brain MRIs within 7 and 30 days, respectively. Only 4.1% of patients were referred to the ED within a day of diagnosis. Ophthalmologists diagnosed the majority (78.7%) of RAOs compared to neurologists (0.6%). Patients diagnosed by ophthalmologists were significantly more likely to have carotid ultrasound within 7 days, but those diagnosed by neurologists were more likely to have echocardiogram, MRI, and ED referral (p < .01 for all comparisons). The rates of adherence to the AAO care guidelines increased significantly between 2002 and 2020 (p < .01).

CONCLUSIONS

The referral and work-up practices demonstrated in this new RAO diagnosis patient cohort have improved with time but are still far below the standard recommended by the AAO.

Primary Monocanalicular Stent Intubation for Children With Congenital Nasolacrimal Duct Obstruction: Surgical Outcome and Risk Factors

PURPOSE

To determine the risk factors impacting the surgical success of primary monocanalicular stent intubation for congenital nasolacrimal duct obstruction (CNLDO).

METHODS

This is a retrospective interventional case series of patients 18 years and younger treated more than a 12-year period with monocanalicular stent intubation with inferior turbinate fracture for CNLDO by a single surgeon. Patients with dacryocystoceles, dacryocystitis, Down syndrome and previous tear duct surgery were excluded. An intraoperative grading scale of tear duct stenosis, date of stent removal, stent length, and postoperative symptoms were recorded. Surgical success was defined as the complete resolution of symptoms.

RESULTS

One thousand four hundred sixty-nine stents were placed in 1,001 pediatric participants (533 unilateral, 468 bilateral). The mean age at surgery was 1.86 years (0.1-18.07). The mean follow up was 34.99 months (0.43-134.3) with mean in-office stent removal at 3.41 months (0.63-36.9). Early stent loss occurred in 14.8% intubations (217/1,469). The overall success rate was 92.4% (1,357/1,469 eyes). Subjects less than the age of 4 years had a success rate of 92.8% (1,296/1,397) compared with 84.7% (61/72) in children more than 4. In multivariable analysis, bilateral surgery, severe tear duct stenosis, and early stent loss were significantly associated with higher risk of surgical failure.

CONCLUSIONS

Severe tear duct stenosis, early stent loss, and bilateral surgery were significant risk factors for surgical failure. While the success rate stratified by age at surgery suggested a lower success after the age of 4. Primary monocanalicular stent intubation is an effective and safe treatment for CNLDO sparing a child the need for multiple staged surgeries.

Thiazolidinedione use and retinal fluid in the comparison of age-related macular degeneration treatments trials

Background

Thiazolidinediones, commonly used antidiabetic medications, have been associated with an increased risk of development of diabetic macular oedema and increased vascular endothelial cell permeability. Macular neovascularisation in age-related macular degeneration (AMD) and associated fluid leakage may be influenced by thiazolidinediones. This study aims to determine the association between thiazolidinedione usage and retinal morphological outcomes or visual acuity (VA) in patients treated with bevacizumab or ranibizumab for neovascular AMD (nAMD).

Methods

Secondary analysis of data from the Comparison of Age-related Macular Degeneration Treatments Trials. Participant self-reported diabetes status and thiazolidinedione usage at baseline. VA, intraretinal, subretinal and subretinal pigment epithelium fluid, and foveal thickness of retinal layers were evaluated at baseline and during 2-year follow-up. Comparisons of outcomes between thiazolidinedione usage groups were adjusted by macular neovascularisation lesion type in multivariable regression models.

Results

Patients taking thiazolidinedione (n=30) had lower adjusted mean VA score at baseline (difference −6.2 letters; p=0.02), greater proportion with intraretinal fluid (IRF) at year 2 (75% vs 50%, adjusted OR 2.8; p=0.04), greater mean decrease in subretinal tissue complex thickness from baseline at year 1 (difference −75.1 um; p=0.02) and greater mean decrease in subretinal thickness at year 1 (difference −41.9 um; p=0.001) and year 2 (difference −43.3 um; p=0.001).

Conclusions

In this exploratory analysis, patients with diabetes taking thiazolidinediones and treated with bevacizumab or ranibizumab for nAMD had worse baseline mean VA, greater reductions in subretinal and subretinal tissue complex thickness from baseline, and greater proportions with IRF comparing to patients not taking thiazolidinediones.

Trial registration number

ClinicalTrials.gov NCT00593450.

Predominantly Persistent Intraretinal Fluid in the Comparison of Age-related Macular Degeneration Treatments Trials (CATT)

PURPOSE

To describe predominantly persistent intraretinal fluid (PP-IRF) and its association with visual acuity (VA) and retinal anatomic findings at long-term follow-up in eyes treated with pro re nata (PRN) ranibizumab or bevacizumab for neovascular age-related macular degeneration.

DESIGN

Cohort within a randomized clinical trial PARTICIPANTS: Participants in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT) assigned to PRN treatment.

METHODS

IRF presence on optical coherence tomography (OCT) scans was assessed at baseline and monthly follow-up visits by the Duke OCT Reading Center. PP-IRF through week 12, year 1, and year 2 were defined as IRF presence at baseline and ≥80% of follow-up visits. Among eyes with baseline IRF, mean VA scores (letters) and change from baseline were compared between eyes with and without PP-IRF. Adjusted mean VA scores and change from baseline were also calculated using linear regression analysis to account for baseline patient features identified as predictors of VA in previous CATT studies. Outcomes were also adjusted by concomitant predominantly persistent subretinal fluid.

PRIMARY OUTCOME MEASURES

Predominantly persistent intraretinal fluid through week 12, year 1, and year 2, VA score and VA change, Scar development at year 2 RESULTS: Among 363 eyes with baseline IRF, 108 (29.8%) had PP-IRF through year 1 and 95 (26.1%) through year 2. Comparing eyes with and without PP-IRF through year 1, mean 1-year VA score was 62.4 vs. 68.5 (p=0.002) and was 65.0 vs. 67.4 after adjustment (p=0.13). PP-IRF through year 2 was associated with worse adjusted 1-year mean VA score (64.8 vs. 69.2; P=0.006) and change (4.3 vs. 8.1; P=0.01), and 2-year mean VA score (63.0 vs. 68.3; P=0.004) and change (2.4 vs. 7.1; P=0.009). PP-IRF through year 2 was associated with higher 2-year risk of scar development (adjusted hazard ratio=1.49; P=0.03).

CONCLUSIONS

Approximately one-quarter of eyes had PP-IRF through year 2. PP-IRF through year 1 was associated with worse long-term VA, but the relationship disappeared after adjustment for baseline predictors of VA. PP-IRF through year 2 was independently associated with worse long-term VA and scar development.

Self-identified Black Race as a Risk Factor for Intraocular Pressure Elevation and Iritis Following Prophylactic Laser Peripheral Iridotomy

PRCIS

In primary angle closure suspects (PACS), self-identified Black race was a risk factor for intraocular pressure (IOP) elevation and iritis following laser peripheral iridotomy (LPI). Laser type was not associated with either immediate post-LPI IOP elevation or iritis in multivariate analysis.

PURPOSE

The aim was to determine the impact of laser type and patient characteristics on the incidence of IOP elevation and iritis after LPI in PACS.

MATERIALS AND METHODS

The electronic medical records of 1485 PACS (2407 eyes) who underwent either neodymium-doped yttrium-aluminum-garnet or sequential argon and neodymium-doped yttrium-aluminum-garnet LPI at the University of Pennsylvania between 2010 and 2018 were retrospectively reviewed. Average IOP within 30 days before LPI (baseline IOP), post-LPI IOP within 1 hour, laser type, laser energy, and the incidence of new iritis within 30 days following the procedure were collected. Multivariate logistic regression accounting for intereye correlation was used to assess factors associated with incidence of post-LPI IOP elevation and iritis, adjusted by age, sex, surgeon, and histories of autoimmune disease, diabetes, and hypertension.

RESULTS

The incidence of post-LPI IOP elevation and iritis were 9.3% (95% confidence interval: 8.1%-10.5%) and 2.6% (95% CI: 1.9%-3.2%), respectively. In multivariate analysis, self-identified Black race was a risk factor for both IOP elevation [odds ratio (OR): 2.08 compared with White; P=0.002] and iritis (OR: 5.07; P<0.001). Higher baseline IOP was associated with increased risk for post-LPI IOP elevation (OR: 1.19; P<0.001). Laser type and energy were not associated with either post-LPI IOP elevation or iritis (P>0.11 for all).

CONCLUSIONS

The incidence of immediate IOP elevation and iritis following prophylactic LPI was higher in Black patients independent of laser type and energy. Heightened vigilance and increased medication management before and after the procedure are suggested to help mitigate these risks.

Statin Use and the Risk of Progression to Vision Threatening Diabetic Retinopathy

PURPOSE

This study aims to assess the effect of statins on progression from nonproliferative diabetic retinopathy (NPDR) to vision-threatening diabetic retinopathy (VTDR), proliferative diabetic retinopathy (PDR) or diabetic macular edema (DME).

METHODS

Two cohort studies using a U.S. medical claims database from 2002 to 2019 including NPDR patients 18 years or older. A risk factor analysis performed a time-updating cox regression model assessing statin usage. A second new-user active comparator design analysis replicating a previously published study. Main outcomes included a new diagnosis of VTDR (composite of either PDR or DME) or DME and PDR individually for the risk factor study and included additional outcomes of new DR, NPDR, vitreous hemorrhage (VH) and tractional retinal detachment (TRD) for the new user study.

RESULTS

Risk factor analysis included 66 617 statin users with NPDR at baseline and 83 365 nonstatin users. Of these, 27 325 (18.2%) progressed to VTDR, 4086 (2.71%) progressed to PDR, and 22 750 (15.1%) progressed to DME. After multivariable analysis, no protective effect of statin use was found for progression to VTDR, PDR, or DME (HR = 1.01-3, p >0.33 for all comparisons). Replicated new user design analysis also showed no protective effect for statins on risk of development of DR (HR = 1.03, 95% CI: 0.99-1.07, p = 0.13), PDR (HR = 0.89, 95% CI: 0.79-1.02, p = 0.09), DME (HR = 0.94, 95% CI: 0.86-1.03, p = 0.21), VH (HR = 1.00, 95% CI: 0.86-1.16, p = 0.99), and TRD (HR = 1.11, 95% CI: 0.89-1.38, p = 0.36).

CONCLUSION

Statin use was found not to be protective for progression of DR regardless of study methodology. These results suggest that the specifics of the population studied rather than differing study methodology are important in assessing the effect of statins on DR progression.

Colonoscopy utilization and outcomes in older adults: Data from the New Hampshire Colonoscopy Registry

BACKGROUND

Colonoscopy is frequently performed in older adults, yet data on current use, and clinical outcomes of and follow-up recommendations after colonoscopy in older adults are lacking.

METHODS

This was an observational study using the New Hampshire Colonoscopy Registry of adults age ≥65 years undergoing colonoscopy for screening, surveillance of prior polyps, or evaluation of symptoms. The main outcomes were clinical findings of polyps and colorectal cancer and recommendations for future colonoscopy by age.

RESULTS

Between 2009 and 2019, there were 42,611 colonoscopies, of which 17,527 (41%) were screening, 19,025 (45%) surveillance, and 6059 (14%) for the evaluation of symptoms. Mean age was 71.1 years (SD 5.0), and 49.3% were male. The finding of colorectal cancer was rare (0.71%), with the highest incidence among diagnostic examinations (2.4%). The incidence of advanced polyps increased with patient age from 65-69 to ≥85 years for screening (7.1% to 13.6%; p = 0.05) and surveillance (9.4% to 12.0%; p < 0.001). Recommendations for future colonoscopy decreased with age and varied by findings at current colonoscopy. In patients without any significant findings, 85% aged 70-74 years, 61.9% aged 75-79 years, 39.1% aged 80-84 years, and 27.4% aged ≥85 years (p < 0.001) were told to continue colonoscopy. Among patients with advanced polyps, 97.2% aged 70-74 years, 89.6% aged 75-79 years, 78.4% aged 80-84 years, and 66.7% aged ≥85 years were told to continue colonoscopy (p < 0.001).

CONCLUSIONS

Within this comprehensive statewide registry, clinical findings during colonoscopy varied by indication and increased with age. Overall rates of finding advanced polyps and colorectal cancer are low. Older adults are frequently recommended to continue colonoscopy despite advanced age and insignificant clinical findings on current examination. These data inform the potential benefits of ongoing colonoscopy, which must be weighed with the low but known potential immediate and long-term harms of colonoscopy, including cost, psychological distress, and long lag time to benefit exceeding life expectancy.

Outcomes of Resident Performed Hydrus, iStent, and Kahook Glaucoma Procedures in a Predominantly African American Population

PRCIS

This retrospective study characterized the efficacy and safety of 3 different microinvasive glaucoma surgery (MIGS) procedures in a predominantly African American population at the Philadelphia Veterans Affairs Hospital (Hydrus, Kahook, iStent), demonstrating no significant difference in intraocular pressure (IOP) and medication reduction between the 3 at long-term follow-up.

PURPOSE

To compare the efficacy and safety of 3 different MIGS procedures in a predominantly African American population.

METHODS

Retrospective cohort study of patients undergoing cataract extraction combined with 1 of 3 MIGS procedures (Hydrus, iStent, Kahook) at the Philadelphia Veterans Affairs Medical Center between January 1, 2015 and November 1, 2020. Analysis of variance and regression models were used to compare reduction in IOP and medication use among 3 MIGS types.

RESULTS

A total of 123 eyes of 112 patients were included, including 56 (45.5%) eyes for Hydrus, 40 (32.5%) eyes for iStent, and 27 (22.0%) eyes for Kahook. Adjusted mean IOP reduction was greater for Hydrus at postoperative day 1 (-4.49 vs. -1.76 for iStent and -1.69 for Kahook, P=0.05 and greater for Kahook at postoperative week 1 (-2.53 vs. +0.70 for iStent vs. -1.41 for Hydrus, P=0.02), but did not differ significantly between MIGS types at subsequent postoperative visits (all P>0.05). In multivariable analysis, MIGS type was not significantly associated with reduction in IOP or medication use at 9 to 12 months postoperatively. There were no significant differences in complication rates across MIGS types.

CONCLUSION

In this study, the difference in IOP lowering and medication reduction postoperatively between the Hydrus, iStent, and Kahook was not statistically significant after postoperative day 1. More studies are needed to evaluate outcomes of MIGS surgeries in glaucoma populations of different disease severity.

Efficacy of an Intranasal Tear Neurostimulator in Sjögren Syndrome Patients

PURPOSE

To assess the efficacy and safety of an intranasal tear neurostimulator (ITN) device in Sjögren syndrome (SS) patients.

METHODS

This was a two-visit prospective, randomized, controlled, same-day crossover study in participants with SS. Inclusion criteria were assessed at a baseline screening visit and included an Ocular Surface Disease Index (OSDI) score ≥13, and a Schirmer with anesthesia ≤10 mm/5 min (in at least one eye), with a cotton swab stimulation induced increase of ≥4 mm in the same eye. Participants returned for the application visit, where they received intranasal and extranasal applications of the ITN in random sequence, separated by at least 60 min. Schirmer scores were measured in both eyes after each application and compared to baseline values. Generalized linear models were performed to compare the change in Schirmer scores from baseline, and generalized estimating equations were used to account for correlations from repeated measurements in the same eye and measurements from two eyes of the same patient.

RESULTS

Fifty-five participants were screened and 35 were enrolled (all female), ranging in age from 31 to 72 years (mean, 57 years). The baseline OSDI score ranged from 14 to 91 (mean, 50.5), and the baseline Schirmer score had a mean (SD) of 6.4 (3.5) ranging from 0 to 20 (mm/5min). Improvement in Schirmer scores was significantly greater for intranasal device application (13.5 mm/5min, 95% CI: 10.4, 16.5) compared to extranasal device application (0.8mm/5min, 95% CI: -0.9, 2.4) (p<0.0001). The effects of the intranasal device application were significant regardless of the participant's baseline Schirmer score and systemic SS medication usage (p<0.05).

CONCLUSION

Intranasal application of the ITN device significantly increased tear production in a subset of SS patients compared to baseline and was more effective than extranasal application. While production of the ITN device was recently discontinued, our findings suggest that other therapies that neurostimulate the lacrimal function unit may be effective in a subset of SS patients.

Predominantly Persistent Subretinal Fluid in the Comparison of Age-Related Macular Degeneration Treatments Trials

OBJECTIVE

To describe predominantly persistent subretinal fluid (SRF) in eyes receiving ranibizumab or bevacizumab for neovascular age-related macular degeneration and to compare visual acuity (VA) to eyes with nonpersistent SRF.

DESIGN

Cohort within randomized clinical trial.

PARTICIPANTS

Comparison of Age-related Macular Degeneration Treatments Trials patients assigned to pro re nata treatment.

METHODS

Graders evaluated monthly OCT scans for SRF. Predominantly persistent SRF through week 12 was defined as SRF at baseline and weeks 4, 8, and 12. Predominantly persistent SRF through 1 or 2 years was defined as SRF in 80% or more of visits by years 1 or 2, respectively. Linear regression models including baseline predictors of VA and predominantly persistent intraretinal fluid (IRF) were used to evaluate mean differences in vision outcomes.

PRIMARY OUTCOME MEASURES

Predominantly persistent SRF through year 1, adjusted VA score and VA change, and foveal SRF thickness.

RESULTS

Among 406 eyes with baseline SRF, SRF persisted in 108 eyes (26.6%) through week 12, in 94 eyes (23.2%) through year 1, and in 77 eyes (19.0%) through year 2. Adjusted VA means at year 1 were similar between eyes with predominantly persistent versus non persistent SRF by week 12 (68.1 vs. 70.2 letters; P = 0.18), year 1 (67.6 vs. 70.2 letters; P = 0.11), and year 2 (71.4 vs. 70.9 letters; P = 0.78). Adjusted changes in mean VA at year 1 were similar between eyes with predominantly persistent versus nonpersistent SRF by week 12 (6.3 vs. 7.6 letters; P = 0.38), year 1 (5.5 vs. 7.8 letters; P = 0.14), and year 2 (8.1 vs. 7.7 letters; P = 0.78). Among eyes with predominantly persistent SRF through year 1, foveal SRF was absent in 46 eyes (48.9%), thickness was 1 to 200 μm in 48 eyes (50.0%) and more than 200 μm in 1 eye (1.1%) at year 1.

CONCLUSIONS

Eyes with predominantly persistent and nonpersistent SRF through week 12, year 1, or year 2 showed similar VA outcomes after adjustment for baseline covariates and persistent IRF. At the foveal center, predominantly persistent SRF was most commonly absent or present in small quantities.

Appendectomy Should Be Performed During Minimally Invasive Surgery for Endometriosis

Objectives:

To determine the prevalence of appendiceal histopathology in patients with confirmed endometriosis following minimally invasive surgery (MIS) for endometriosis. To determine whether pre-operative symptoms, age, intra-operative appendiceal appearance, or endometrioma laterality were associated with appendix histopathology in patients with suspected endometriosis.

Methods:

One hundred thirty-five patients ages 16–52 with suspected endometriosis undergoing MIS for endometriosis with concomitant appendectomy at two metropolitan academic hospitals from January 1, 2012 to June 30, 2017 were included in this retrospective chart-review study. Medical records were reviewed for pre-operative symptoms, age, intraoperative appendix appearance, appendix histopathology, histopathologically-confirmed endometriosis, and endometriomas.

Results:

In patients with confirmed endometriosis, the prevalence of all appendiceal histopathology was 25%, which included appendiceal endometriosis (18%), appendiceal tumors (2%), and inflammation (5%). Dyspareunia was the only pre-operative symptom significantly associated with appendiceal histopathology (p = 0.04). The presence of a right endometrioma was associated with appendiceal histopathology (p = 0.009). Additionally, appendiceal histopathology was not significantly associated with age nor intra-operative appendiceal characteristics.

Conclusion:

This manuscript adds to the limited pool of studies regarding appendiceal histopathology and appendiceal tumors in patients with suspected and confirmed endometriosis. On the basis of the high rate of histopathological appendices found in this population; the lack of association with possible diagnostic factors such as age, most pre-operative symptoms, and intra-operative appendiceal characteristics; and the relatively low risks of concomitant appendectomy, we suggest that surgeons consider concomitant appendectomies at the time of MIS for endometriosis.

SYSTEMIC MEDICATION USE AND THE INCIDENCE AND GROWTH OF GEOGRAPHIC ATROPHY IN THE COMPARISON OF AGE-RELATED MACULAR DEGENERATION TREATMENTS TRIALS

PURPOSE

To determine associations of systemic medications with the incidence and growth of geographic atrophy (GA) in participants of the comparison of age-related macular degeneration treatments trials.

METHODS

Participants of comparison of age-related macular degeneration treatments trials with new untreated choroidal neovascularization in the study eye (one study eye per participant) were randomized to receive treatment with bevacizumab or ranibizumab. Participants were released from clinical trial treatment at 2 years and examined at approximately 5 years. Color fundus photographs and fluorescein angiograms taken at baseline, Years 1, 2, and 5 were assessed for the presence and size of GA by two masked graders. Participants were interviewed about systemic medication use at baseline. Systemic medications previously reported to be associated with age-related macular degeneration were evaluated for associations with GA incidence in study eye using univariable and multivariable Cox models and for association with the GA growth using linear mixed effects models.

RESULTS

In multivariable analysis of 1,011 study eyes without baseline GA, systemic medications, including cholinesterase inhibitors, angiotensin-converting enzyme inhibitors, calcium channel blockers, beta-blockers, diuretics, aspirin, steroids, statins, hormone replacement therapy, antacids, and drugs targeting G protein-coupled receptors, were not associated with GA incidence in the study eye (all adjusted hazard ratios ≤1.86, P ≥ 0.18). In multivariable analysis of 214 study eyes with longitudinal GA size measurements, calcium channel blockers were associated with a higher GA growth rate (0.40 vs. 0.30 mm/year, P = 0.02).

CONCLUSION

None of the systemic medications analyzed were associated with GA incidence. However, calcium channel blockers were associated with a higher growth rate of GA in the study eye.

Association of metformin and development of dry age-related macular degeneration in a U.S. insurance claims database

PURPOSE

To assess whether metformin is associated with dry age-related macular degeneration (dAMD) development.

METHODS

In this retrospective cohort study, patients enrolled in a nationwide U.S. medical insurance claims database from 2002 to 2016 were included if they had diabetes mellitus, were ⩾55 years old, and were enrolled for ⩾2 years without a prior AMD diagnosis. The primary exposure was metformin use analyzed as either active or prior use or cumulative metformin dosage over the study period. A time updating Cox proportional hazard regression was used to estimate the hazard ratio of dAMD incidence with metformin exposure.

RESULTS

Among 1,007,226 diabetic enrollees, 53.3% were female and 66.4% were white with a mean hemoglobin A1c of 6.8%. Of eligible enrollees, 166,115 (16.5%) were taking metformin at the index date. Over the study period, 29,818 (3.0%) participants developed dAMD. In the active versus prior use of metformin model, active use conferred an increased hazard of developing dAMD (HR, 1.08; 95% CI, 1.04-1.12) while prior use had a decreased hazard (HR, 0.95; 95% CI 0.92-0.98). The cumulative metformin dosage model showed a significant trend toward increased hazard of dAMD incidence with increasing cumulative dosage (p < 0.001), with the lowest dosage quartile having decreased hazard of dAMD incidence (HR, 0.95; 95% CI, 0.91-0.99) and the highest having increased hazard (HR, 1.07; 95% CI, 1.01-1.13).

CONCLUSIONS

Small, conflicting associations between metformin exposure and development of dAMD were observed depending on cumulative dosage and whether drug use was active, suggesting metformin did not substantially affect the development of dAMD.

Characteristics of Eyes With Good Visual Acuity at 5 Years After Initiation of Treatment for Age-Related Macular Degeneration but Not Receiving Treatment From Years 3 to 5: Post Hoc Analysis of the CATT Randomized Clinical Trial

Importance

Identifying the characteristics of eyes with neovascular age-related macular degeneration (nAMD) that maintain good vision without anti-vascular endothelial growth factor treatment for at least 3 years after management, as occurred in the Comparison of Age-Related Macular Degeneration Treatments Trials (CATT), may have prognostic importance and help in understanding the disease and its treatment.

Objectives

To ascertain the characteristics of eyes in the CATT that retained good vision despite receiving no therapy for 3 years after release from the 2-year CATT treatment protocol.

Design, Setting and Participants

This case-control study analyzed the baseline and follow-up characteristics of eyes with nAMD that were enrolled in the CATT from 43 US clinical centers between February 20, 2008, and December 9, 2009. After initial randomization to 1 of 4 treatment groups (ranibizumab monthly, bevacizumab monthly, ranibizumab as needed, or bevacizumab as needed), at year 1, participants in the monthly groups were rerandomized to continue monthly treatment or to switch to as-needed treatment using the same drug as originally assigned. At year 2, participants were released from the protocol to treatment at the discretion of their ophthalmologist. At year 5, participants were recalled for examination. This present analysis, conducted from December 1, 2018, to September 30, 2019, compared the eyes of 40 participants (referred to as the cessation of treatment with good visual acuity, or CTGVA, group) with the eyes of the remainder of the CATT Follow-up Study (referred to as the other group).

Main Outcomes and Measures

Visual acuity, morphologic characteristics, and number of treatments over 5 years.

Results

Among 625 eyes with nAMD at baseline and a visual acuity measurement at year 5, 40 (6.4%; 95% CI, 4.7%-8.7%) were included in the analysis. These 40 participants, compared with the other group (n = 585), had a lower mean (SD) age of 74.7 (7.3) years (vs 77.7 [7.3] years; P = .01) and included 26 women (65.0%). Baseline characteristics were similar between eyes in the CTGVA and other groups, except for better visual acuity letter score in the study eye (68.8 vs 61.8; P = .001) and the fellow eye (78.4 vs 68.0; P = .01) as well as the presence of blocked fluorescence seen more often in participants in the CTGVA vs the other group (27.5% vs 13.8%; P = .02). Eyes in the CTGVA group with as-needed treatment received fewer mean (SD) injections in year 1 (5.8 [4.0] vs 8.1 [3.5]) and year 2 (7.7 [5.7] vs 13.8 [6.8]) than eyes in the other as-needed group. Mean (SD) visual acuity letter score at 5 years was 79.0 (5.5; Snellen 20/25) in the CTGVA group and 57.5 (24.2; Snellen 20/80) in the other group.

Conclusions and Relevance

These findings suggest that a small proportion of eyes with nAMD can retain good visual acuity with no treatment for at least 3 years after the initial 2 years of treatment. Unique characteristics of eyes that could discontinue treatment while maintaining good visual acuity could not be identified at baseline, but data suggest that not all eyes with this disease may need treatment forever.

Trial Registration

ClinicalTrials.gov Identifier: NCT00593450.

COX-2-derived prostaglandins as mediators of the deleterious effects of nicotine in chronic kidney disease

Tobacco smoking has been identified as a risk factor in the progression of chronic kidney disease (CKD). In previous studies, we showed that nicotine induces cyclooxygenase (COX)-2 expression in vivo and in vitro and that the administration of nicotine in vivo worsens the severity of renal injury in a model of subtotal renal ablation. In the present study, we tested the role of COX-2-derived prostaglandins on the deleterious effects of nicotine in CKD. Sham and 5/6 nephrectomy (5/6Nx) rats received tap water or nicotine (100 μg/mL) in the drinking water for 12 wk. Additional groups also systemically received the COX-2 inhibitor NS-398 (1.5 mg·kg^-1·day^-1 via osmotic minipump). The administration of nicotine worsened renal injury and proteinuria in 5/6Nx rats and increased proteinuria in sham rats. 5/6Nx rats had increased cortical production of the prostaglandins PGE₂, PGI₂, PGD₂, and PGF_2α and of thromboxane A₂. In these rats, nicotine reduced the production of all prostaglandins examined except thromboxane A₂. Treatment with the COX-2 inhibitor NS-398 resulted in complete inhibition of all prostaglandins studied and ameliorated renal injury and proteinuria in 5/6Nx rats on nicotine but not in 5/6 Nx rats on tap water. Nicotine also reduced the expression of megalin in all groups examined, and this was partially prevented by COX-2 inhibition. In the present study, we showed that in CKD, nicotine worsens renal injury at least in part by producing an imbalance in the production of prostaglandins. This imbalance in the production of prostaglandins likely plays a role in the deleterious effects of smoking on the progression of CKD.

ADVERSE CONSEQUENCES OF UNMET NEEDS AMONG INDIVIDUALS WITH DEMENTIA: THE ROLE OF PAID CAREGIVING

Individuals with dementia may enlist help from paid caregivers (i.e. home health aides, personal care attendants) to address increasingly complex care needs. Yet it is unclear what specific tasks paid caregivers help with and how this is related to the individual’s experience of unmet care needs. We used data from the 2015 National Health and Aging Trends Study (NHATS) to examine the association between type and intensity of individual paid caregiver tasks and adverse consequences of unmet needs among community-dwelling adults with dementia. Nearly one half (46%) of those with any functional impairment reported an adverse consequence of an unmet need (e.g., inability to go outside because of lack of help). Individuals who experienced adverse consequences were more likely to receive paid caregiving (37.9% vs. 21.4%, p<0.01). Those who received paid care with an individual task (e.g. toileting) were more likely to report an adverse consequence related to that task (e.g. remaining in wet or soiled clothes 50.2% vs. 41.0%, p=0.21). Paid caregivers provided a median of 15 hours of care per week. For those persons with dementia receiving less hours of care weekly, paid caregivers rarely helped with unscheduled or frequently recurring functional tasks like toileting or eating (<10% of the time). The help received by individuals with dementia was inadequate to meet their care needs. Paid caregiving will only be able to prevent adverse consequences of unmet care needs when the level of paid care provided is better matched to the care needs of the individual with dementia.

Are older drivers' driving patterns during an on-road driving task representative of their real-world driving patterns?

OBJECTIVE

The current study investigated whether older drivers' driving patterns during a customized on-road driving task were representative of their real-world driving patterns.

METHODS

Two hundred and eight participants (male: 68.80%; mean age = 81.52 years, SD = 3.37 years, range = 76.00-96.00 years) completed a customized on-road driving task that commenced from their home and was conducted in their own vehicle. Participants' real-world driving patterns for the preceding 4-month period were also collected via an in-car recording device (ICRD) that was installed in each participant's vehicle.

RESULTS

During the 4-month period prior to completing the on-road driving task, participants' median real-world driving trip distance was 2.66 km (interquartile range [IQR] = 1.14-5.79 km) and their median on-road driving task trip distance was 4.41 km (IQR = 2.83-6.35 km). Most participants' on-road driving task trip distances were classified as representative of their real-world driving trip distances (95.2%, n = 198).

CONCLUSIONS

These findings suggest that most older drivers were able to devise a driving route that was representative of their real-world driving trip distance. Future research will examine whether additional aspects of the on-road driving task (e.g., average speed, proportion of trips in different speed zones) are representative of participants' real-world driving patterns.

The study of the tumor stem cell properties of CD133+CD44+ cells in the human lung adenocarcinoma cell line A549

We studied the tumor stem cell properties of the CD133+CD44+ subpopulation in the human lung adenocarcinoma cell line A549. A549 cells were classified into subpopulations based on differential expression patterns for CD133 and CD44. Cells from different subpopulations were cultured and subcutaneously injected into 32 nude mice. Our results as following, (1) The majority of A549 cells died, whereas only about 4.11% of cells divided and proliferated to form cell clones. (2) The expression of CD133 and CD44 in proliferative cancer cells was statistically significantly different from that in normal A549 cells (p < 0.001). (3) Cell proliferation in group A (CD133+CD44+) was the fastest among all groups. Cell proliferation in A549 cells was slower than in group A but faster than in groups B (CD133-CD44-), C (CD133-CD44+), and D (CD133+CD44-). (4) The tumorigenic capacity in cells from group A was significantly higher than that in cells from groups B (p<0.001), C (p<0.001) and D (p<0.04). In conclusion, CD133+CD44+ cells in the adenocarcinoma cell line A549 have expressive significant cancer stem cell properties with continuous proliferative capacity and differentiation potential.

Characterization of the main effects, epistatic effects and their environmental interactions of QTLs on the genetic basis of yield traits in rice

Main effects, epistatic effects and their environmental interactions of QTLs are all important genetic components of quantitative traits. In this study, we analyzed the main effects, epistatic effects of the QTLs, and QTL by environment interactions (QEs) underlying four yield traits, using a population of 240 recombinant inbred lines from a cross between two rice varieties tested in replicated field trials. A genetic linkage map with 220 DNA marker loci was constructed. A mixed linear model approach was used to detect QTLs with main effects, QTLs involved in digenic interactions and QEs. In total, 29 QTLs of main effects, and 35 digenic interactions involving 58 loci were detected for the four traits. Thirteen QTLs with main effects showed QEs; no QE was detected for the QTLs involved in epistatic interactions. The amount of variations explained by the QTLs of main effect were larger than the QTLs involved in epistatic interactions, which in turn were larger than QEs for all four traits. This study illustrates the ability of the analysis to assess the genetic components underlying the quantitative traits, and demonstrates the relative importance of the various components as the genetic basis of yield traits in this population.

[Growth and metabolism of human skin fibroblasts cultured on microcarriers]

Human foreskin fibroblasts were cultured in vitro on microcarriers in spinners and traditional static flasks. The cultured cells obtained with these approaches were compared in cell shape, cell growth, cell production, and the metabolisms of glucose, lactate, and ammonium. The cells from microcarrier cultures through medium exchange were 8 times more than those from traditional static flasks. It was found that the specific growth rate and specific glucose consumption rate in microcarrier spinner cultures were 0.64/d-1 and 5.56 mmol/10(9) cell/d, respectively, higher than those in static flask cultures. However, the average lactate yield on glucose consumption in spinner cultures was only 0.955 mmol/mmol, lower than that in static flask cultures, 1. 125 mmol/mmol. This indicated that the energy metabolism in spinner cultures was significantly more efficient than that in static flasks. The experimental results from this work suggest that the microcarrier culture system is a suitable way to expand the seeding cells for tissue engineering, due to its ideal cultivation environment provided.

Canine ehrlichiosis caused simultaneously by Ehrlichia canis and Ehrlichia platys

To identify the causative agent of canine ehrlichiosis that has occurred in the suburbs of Guangzhou, China, since 1998, the 16S rRNA gene was amplified and sequenced. Two sequences of 1,482 and 1,483 base pairs were obtained and named as Gzh981 and Gzh982, respectively. The level of similarity of these two was 91.50%, and Gzh981 closely resembled the 16S rRNA gene of Ehrlichia canis, whereas Gzh982 resembled Ehrlichia platys. We therefore conclude that E. canis and E. platys together caused recent outbreaks of canine ehrlichiosis in China.

[On-line measurement of oxygen uptake rate in the cultivation of Vero cells using the dynamic method]

The oxygen uptake rate(OUR) during the cultivation of Vero cells in 1.5 L CelliGen bioreactor was on-line determined using the dynamic method. The results showed that the cell growth and metabolic state during the exponential growth phase was lineally related to the OUR. This implies that the on-line measurement of OUR can be used to promptly monitor the physiological state of cultured cells and to efficiently avoid contamination because of frequent sampling in the large-scale cultivation of mammalian cells.

Aerosol delivery of robust polyethyleneimine-DNA complexes for gene therapy and genetic immunization

Aerosol delivery of plasmid DNA to the lungs offers the possibility of direct application of gene preparations to pulmonary surfaces as a means of treating a variety of genetic pulmonary disorders. However, the process of jet nebulization rapidly degrades naked DNA, viral vectors, and many lipid-based formulations. While complexing DNA with cationic lipids has been shown to significantly stabilize plasmid DNA, losses of biological activity often occur during nebulization, severely limiting the efficiency of aerosol delivery of many such complexes. In conjunction with the design of aerosol delivery systems appropriate for DNA delivery, we have developed formulations using polyethyleneimine (PEI, a polycationic polymer) and DNA that result in a high level of pulmonary transfection (10- to 100-fold greater than many cationic lipids) and are stable during nebulization. In addition, these PEI-based formulations exhibit a high degree of specificity for the lungs. The properties of PEI-based formulations that make them resistant to nebulization and efficient as DNA delivery vectors for pulmonary sites have been investigated. Potential applications of this technology, including the use of aerosolized PEI-DNA for genetic immunization, are discussed.

Attachment kinetics of vero cells onto CT-3 microcarriers

The effects of cell seeding density, microcarrier concentration, agitation speed and age of seeding cells on the rate of cell attachment to the surface of CT-3 microcarriers were investigated. It was shown that the attachment followed first-order kinetics. When either the cell seeding density or the microcarrier concentration was increased, the kinetic constant increased due to an increase in the probability of collision between cells and microcarriers. However, at higher microcarrier concentrations, the increase in the kinetic constant with increasing microcarrier concentration was not significant. Cell attachment was decelerated upon increasing the agitation speed because of the shorter cell-microcarrier contact time. In addition, it was also demonstrated that cell attachment occurred more efficiently when seeding cells from the middle or early exponential growth phase were used. The process of cell attachment onto CT-3 microcarriers was investigated, and our results showed that the attachment stage was the rate-limiting step. These results will facilitate the optimization of the Vero cell culture process.

Identification of profilin and src homology 3 domains as binding partners for Drosophila enabled

Drosophila Enabled (Ena) was first identified as a genetic suppressor of mutations in the Abelson tyrosine kinase and subsequently was shown to be a member of the Ena/vasodilator-stimulated phosphoprotein family of proteins. All members of this family have a conserved domain organization, bind the focal adhesion protein zyxin, and localize to focal adhesions and stress fibers. Members of this family are thought to be involved in the regulation of cytoskeleton dynamics. The Ena protein sequence has multiple poly-(L-proline) residues with similarity to both profilin and src homology 3 binding sites. Here, we show that Ena can bind directly to the Drosophila homolog of profilin, chickadee. Furthermore, Ena and profilin were colocalized in spreading cultured cells. We report that the proline-rich region of Ena is responsible for this interaction as well as for mediating binding to the src homology 3 domain of the Abelson tyrosine kinase. These data support the hypothesis that Ena provides a regulated link between signal transduction and cytoskeleton assembly in the developing Drosophila embryo.

Triple helix formation: binding avidity of acridine-conjugated AG motif third strands containing natural, modified and surrogate bases opposed to pyrimidine interruptions in a polypurine target

A critical issue for the general application of triple-helix-forming oligonucleotides (TFOs) as modulators of gene expression is the dramatically reduced binding of short TFOs to targets that contain one or two pyrimidines within an otherwise homopurine sequence. Such targets are often found in gene regulatory regions, which represent desirable sites for triple helix formation. Using intercalator-conjugated AG motif TFOs, we compared the efficacy and base selectivity of 13 different bases or base surrogates in opposition to pyrimidines and purines substituted into selected positions within a paradigm 15-base polypurine target sequence. We found that substitutions closer to the intercalator end of the TFO (positions 4-6) had a more deleterious effect on the dissociation constant (K d) than those farther away (position 11). Opposite T residues at position 11, 3-nitropyrrole or cytosine in the TFO provided adequate binding avidity for useful triplex formation (K ds of 55 and 110 nM, respectively). However, 3-nitropyrrole was more base selective than cytosine, binding to T >/=4 times better than to A, G or C. None of the TFOs tested showed avid binding when C residues were in position 11, although the 3-nitropyrrole-containing TFO bound with a K d of 200 nM, significantly better than the other designs. Molecular modeling showed that the 3-nitropyrrole.T:A triad is isomorphous with the A.A:T triad, and suggests novel parameters for evaluating new base triad designs.

A 15-base acridine-conjugated oligodeoxynucleotide forms triplex DNA with its IL-2R alpha promoter target with greatly improved avidity

Attachment of 6,9-diamino-2-methoxyacridine to the 5' end of a purine-rich oligodeoxynucleotide targeting a 15 bp oligopurine oligopyrimidine stretch in the promoter region of the interleukin-2 receptor alpha chain (IL-2R alpha) gene results in an approximately 500-fold increase in its triplex forming avidity as determined by both band shift assay and DMS footprinting (Kd lowered from 2.5 microM to 5 nM). This oligonucleotide participates in Mg(2+)-dependent three-stranded DNA formation in which it is oriented antiparallel relative to the purine strand of the target duplex as determined by acridine moiety sensitized photoreactivity with the target duplex DNA. The oligonucleotides used in these studies were synthesized with a 3-amino-2-hydroxypropyl group at the 3' end to protect against exonucleolytic degradation for future in vivo applications. The 3'-amino group underwent partial removal, probably during the NaOH deprotection step. Both the 3'-amino and the 3'-free forms of the oligo have the same binding avidity and specificity. The interaction of the third strand with its target is sequence specific and can be essentially abolished by a point G-->T transversion 4 bases away from the 3' end of the target oligopurine block or severely reduced by other mutations within the target duplex. Thus, the attachment of the acridine moiety to the 5' end of the oligonucleotide does not seem to substantially compromise the sequence specificity of binding. Additionally, the oligonucleotide composed of G and A nucleotides was found to be superior to the oligonucleotide containing G and T residues since the difference in avidity of binding to the same target site was 17-fold.