Academic versus Community Retinal Surgery for Primary Retinal Detachment: Characteristics, Duration, and Value Analysis of Teaching Modifier.

PURPOSE: To compare operative time and case characteristics of primary rhegmatogenous retinal detachment (RRD) repairs between academic and community vitreoretinal surgeons. DESIGN: A retrospective, observational clinical study. SUBJECTS: Patients who underwent primary RRD repair surgeries at Massachusetts Eye and Ear between 2019 and 2021. METHODS: A random sample of 20 vitreoretinal surgeons distributed evenly among the academic or community setting was selected. Fifteen consecutive cases of primary RRD repair surgeries were included from each surgeon. A cost analysis was performed for the teaching modifier for the physician fee and for hospital costs. MAIN OUTCOME MEASURES: Length of surgery. RESULTS: Of 300 primary RRD repairs, fellows were present in 75%, which comprised all academic surgeon cases and 50% of community surgeon cases, P < 0.001. Mean operation length was shorter for community surgeon cases without fellows (55.0 ± 24.1) than either academic (73.0 ± 30.8) or community surgeon cases with fellows (75.7 ± 32.5) (P < 0.001). There was a higher percentage of macula-off RRDs in academic versus community surgeon cases (52.7% vs. 38.0%, P = 0.002) and higher rates of combined scleral buckle (SB)/pars plana vitrectomy (PPV) repairs (14% vs. 3%, P < 0.001). When excluding combined SB/PPV cases, there was no difference in operative time between academic and community surgeon cases. Among RRDs repaired by PPV only, there was a 31.4% (16.6 minutes) greater procedure duration in cases with fellows compared with cases without fellows (P < 0.001). Covariates associated with greater surgery time: addition of an SB (ß = 32.6), membrane peel (ß = 18.5), presence of a fellow (ß = 14.5), proliferative vitreoretinopathy (ß = 12.8), and greater number of retinal breaks (ß = 2.4). The teaching modifier adds 16% extra reimbursement ($184.16) to the physician fee, which is 50.9% of what is necessary to cover the percentage increase in surgeon time (31.4%). Using a time-driven activity-based costing for hospital costs, the extra 16.6 minutes leads to an additional $1038.00, which is 5.6 times more than the reimbursement for the modifier. CONCLUSIONS: Retinal detachment repair cases performed by academic surgeons are more likely to be macula-off and include the addition of an SB, which drive longer operative times. Medicare's reimbursement of the assistant modifier in a teaching facility significantly undercompensates the time-driven activity-based costing of trainee participation. FINANCIAL DISCLOSURE(S): Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

Extensive Endolaser During Vitrectomy for Primary Rhegmatogenous Retinal Detachment Is Associated With Epiretinal Membrane Formation.

BACKGROUND AND OBJECTIVE: Epiretinal membrane (ERM) formation, a common complication following pars plana vitrectomy (PPV) for primary rhegmatogenous retinal detachment (RRD) repair, is associated with vision loss and metamorphopsias. Although laser retinopexy is generally associated with ERM formation, the correlation between the extent of laser treatment and ERM formation during PPV is not well established. The aim of this study was to identify risk factors associated with ERM formation including extend of endolaser retinopexy after PPV for primary RRD. PATIENTS AND METHODS: A retrospective, observational case series of 181 consecutive patients (185 eyes) who underwent PPV for primary RRD repair by a single surgeon was performed. Charts were reviewed by two independent reviewers, and de-identified data including patient characteristics and intraoperative findings such as number of laser spots placed were recorded. RESULTS: Postoperative ERM formation occurred in 75 eyes (40.5%) of which 68 (90.6%) were Stage 1, two (2.6%) were Stage 2, three (4%) were Stage 3, and two (2.6%) were Stage 4. Only one patient required secondary PPV for visually significant ERM. Patients with ERM had significantly more laser spots compared with patients with no ERM, with a mean of 807 and 519 laser spots respectively (95% CI: 387.6 to -187.3; P < 0.0001). Univariable analysis identified ≥750 endolaser spots (odds ratio [OR] = 4.0, 95% CI: 2.0 to 8.4; P < 0.0001), ≥4 retinal tears (OR = 2.8, 95%: CI 1.4 to 6.4; P = 0.005), and female sex (OR = 2.0, 95% CI: 1.1 to 3.7; P = 0.02) as significantly associated factors. After adjusting for potential confounding factors (ie, age, sex, macula status, lattice degeneration, length of symptoms, vitreous hemorrhage, number of endolaser spots, number of retinal tears) in multivariable logistic regression, ≥ 750 endolaser spots (OR = 2.4; P = 0.04) and female sex (OR = 2.4; P = 0.03) persisted as significant independent factors. CONCLUSIONS: Our study identified ≥ 750 laser spots and female sex as independent risk factors for ERM formation following PPV for RRD with an OR of 2.4 each. Although the incidence of ERM formation was generally high (40.5%), only one case required secondary PPV with ERM peeling, and visual outcomes were comparable between patients with and without ERM at final follow up. While endolaser photocoagulation is critical for successful RRD repair, consideration of the risk of ERM formation with extensive laser exposure is warranted. [Ophthalmic Surg Lasers Imaging Retina 2024;55:326-333.].

Distinguishing spheno-orbital metastatic prostate cancer mimicking a meningioma using novel 18F-PSMA PET/CT imaging.

A 78-year-old man presented with acute-onset left temporal pain, eyelid swelling, and double vision. Computed tomography (CT) demonstrated a left sphenoid wing mass with extra-osseous intra-orbital and intracranial extension, thought to be a typical sphenoid wing meningioma by the primary team. The patient was admitted for an urgent craniotomy, which was planned for the following day. However, upon consultation with ophthalmic plastic surgery, concern was raised for an alternative diagnosis given the atypical timeline, inflammatory changes, and uncharacteristic imaging findings of mixed lytic and sclerotic bony changes without hyperostosis on CT and extensive peri-lesional dural thickening and enhancement on magnetic resonance imaging. A serum prostate-specific antigen was elevated to 206 ng/mL. Subsequent positron emission tomography (PET)/CT using 18F-fluorodeoxyglucose radiotracer was negative for metastatic disease. A prostate-specific membrane antigen (PSMA) PET/CT was then obtained and demonstrated extensive metastases. An orbital biopsy revealed poorly differentiated prostatic adenocarcinoma. The significant incongruence between the standard PET/CT and PSMA PET/CT highlights the value of this novel advanced radiographic modality in narrowing the differential diagnosis and determining the extent of disease. Findings of widespread metastasis on the PSMA PET/CT ultimately helped to avoid a large, morbid neurosurgical intervention in this patient, allowing for a minimally invasive orbital biopsy to characterize the tumor for therapeutic targeting.

pH-sensitive cationic nanoparticles for endosomal cell-free DNA scavenging against acute inflammation.

Cell-free DNA (cfDNA) released from dead cells could be a player in some autoimmune disorders by activating Toll-like receptor 9 (TLR9) and inducing proinflammatory cytokines. Cationic nanoparticles (cNPs) address cfDNA clearance, yet challenges persist, including toxicity, low specificity and ineffectiveness against endocytosed cfDNA. This study introduced pH-sensitive cNPs, reducing off-target effects and binding cfDNA at inflammatory sites. This unique approach inhibits the TLR9 pathway, offering a novel strategy for inflammation modulation. Synthesized cNPs, with distinct cationic moieties, exhibit varied pKa values, enhancing cfDNA binding. Comprehensive studies elucidate the mechanism, demonstrating minimal extracellular binding, enhanced endosomal DNA binding, and optimal tumor necrosis factor-α suppression. In a traumatic brain injury mice model, pH-sensitive cNPs effectively suppress inflammatory cytokines, highlighting their potential in acute inflammation regulation.

Cystic-Appearing Eyelid Lesion in a 62-Year-Old Man.

A 62-year-old male was referred for evaluation of a painless right lower-eyelid lesion noted during routine glaucoma follow-up. The lesion had been present for 3 years with slow, gradual enlargement. What would you do next?

Persistent Inflammation Associated With HLA-B27 After Pars Plana Vitrectomy With Scleral Buckle Placement.

Purpose: To report 2 cases of persistent inflammation associated with human leukocyte antigen-B27 (HLA-B27) after pars plana vitrectomy (PPV) with scleral buckling. Methods: Two cases were analyzed. Results: A 47-year-old man had pars plana vitrectomy (PPV), scleral buckle (SB) placement, and endolaser for a macula-on rhegmatogenous retinal detachment (RRD). A 61-year-old man also had uneventful PPV, SB placement, and endolaser for a macula-off RRD. Postoperatively, both patients reported eye pain and had persistent intraocular inflammation. Both were found to be HLA-B27 positive despite having no previous signs or symptoms that would warrant HLA-B27 testing. Conclusions: Discovering the source of prolonged postoperative inflammation is critical in initiating the correct treatment and removing suspicion of infection. Although intraocular inflammation associated with HLA-B27 does not often present initially after surgery, HLA-B27 testing should be considered in cases of persistent, unexpected postoperative inflammation.

Stress regulates Alzheimer's disease progression via selective enrichment of CD8+ T cells.

This study investigates stress's impact on Alzheimer's disease (AD) using male APP/PS1 transgenic mice. Negative stressors (chronic social defeat, restraint) and positive hedonia (environmental enrichment, EE) were applied. Stress worsens AD pathology, while EE slows progression. Brain RNA sequencing reveals interleukin-6 (IL-6) and IL-10 as key stress-related AD regulators. Flow cytometry shows that the CD8+/CD4+ T cell ratio shifts in response to stress exposure and EE. Stress exposure increases CD8+/CD4+ ratio, opposite to EE. Depletion and enrichment of CD8+ T cells both accelerate AD, indicating immune intervention's negative impact. Stress management and balanced immunity may aid AD therapy, highlighting novel potential treatment.

Protocol for generating in vitro glioma models using human-induced pluripotent- or embryonic-stem-cell-derived cerebral organoids.

In glioma modeling, existing organoid protocols lack the ability to replicate glioma cell invasion and interaction with normal brain tissue. Here, we present a protocol for generating in vitro brain disease models using human-induced pluripotent- or embryonic-stem-cell-derived cerebral organoids (COs). We describe steps for forming glioma organoids by co-culturing forebrain organoids with U-87 MG cells. We also detail vibratome sectioning of COs to prevent cell death and enhance contact between U-87 MG cells and cerebral tissues.

Comparison of the Safety and Efficacy of a 3-Dimensional Heads-up Display vs a Standard Operating Microscope in Retinal Detachment Repair.

Purpose: To evaluate the safety, efficacy, and efficiency of the Ngenuity 3-dimensional (3D) heads-up display (HUD) visualization system for primary rhegmatogenous retinal detachment (RRD) repair at a large academic medical center in the United States. Methods: This retrospective review comprised consecutive patients aged 18 years or older who had primary RRD repair (pars plana vitrectomy [PPV] alone or combined PPV and scleral buckle) performed by the same fellowship-trained vitreoretinal surgeon using the 3D visualization system and a traditional standard operating microscope (SOM) at Massachusetts Eye and Ear from June 2017 to December 2021. The minimum follow-up was 90 days. Results: The 3D HUD group comprised 50 eyes of 47 patients and the SOM group, 138 eyes of 136 patients. There were no between-group differences in single surgery anatomic success rates at 3 months (98% HUD vs 99% SOM; P = 1.00) or at the last follow-up (94% HUD vs 98% SOM; P = .40). The rate of postoperative proliferative vitreoretinopathy was similar between the 2 groups (3 months: 3% HUD vs 5% SOM, P = .94; last follow-up, 2% HUD vs 3% SOM, P = .93). There was no difference in the mean duration of surgery (57.4 ± 28.9 minutes HUD vs 59.4 ± 29.9 minutes SOM; P = .68). Conclusions: Anatomic and functional outcomes, in addition to surgical efficiency, of noncomplex primary RRD repair with a 3D HUD system were similar to those of surgery performed with an SOM.

A Validated Method to Identify Neuro-Ophthalmologists in a Large Administrative Claims Database.

BACKGROUND: Validated methods to identify neuro-ophthalmologists in administrative data do not exist. The development of such method will facilitate research on the quality of neuro-ophthalmic care and health care utilization for patients with neuro-ophthalmic conditions in the United States. METHODS: Using nationally representative, 20% sample from Medicare carrier files from 2018, we identified all neurologists and ophthalmologists billing at least 1 office-based evaluation and management (E/M) outpatient visit claim in 2018. To isolate neuro-ophthalmologists, the National Provider Identifier numbers of neuro-ophthalmologists in the North American Neuro-Ophthalmology Society (NANOS) directory were collected and linked to Medicare files. The proportion of E/M visits with International Classification of Diseases-10 diagnosis codes that best distinguished neuro-ophthalmic care ("neuro-ophthalmology-specific codes" or NSC) was calculated for each physician. Multiple logistic regression models assessed predictors of neuro-ophthalmology specialty designation after accounting for proportion of ophthalmology, neurology, and NSC claims and primary specialty designation. Sensitivity, specificity, and positive predictive value (PPV) for varying proportions of E/M visits with NSC were calculated. RESULTS: We identified 32,293 neurologists and ophthalmologists who billed at least 1 outpatient E/M visit claim in 2018 in Medicare. Of the 472 NANOS members with a valid individual National Provider Identifier, 399 (84.5%) had a Medicare outpatient E/M visit in 2018. The model containing only the proportion of E/M visits with NSC best predicted neuro-ophthalmology specialty designation (odds ratio 1.05 [95% confidence interval 1.04, 1.05]; P < 0.001; area under the receiver operating characteristic [AUROC] = 0.91). Model predictiveness for neuro-ophthalmology designation was maximized when 6% of all billed claims were for NSC (AUROC = 0.89; sensitivity: 84.0%; specificity: 93.9%), but PPV was low (14.9%). The threshold was unchanged when limited only to neurologists billing ≥1% ophthalmology claims or ophthalmologists billing ≥1% neurology claims, but PPV increased (33.3%). CONCLUSIONS: Our study provides a validated method to identify neuro-ophthalmologists who can be further adapted for use in other administrative databases to facilitate future research of neuro-ophthalmic care delivery in the United States.

The interdependent transport of yeast vacuole Ca2+ and H+ and the role of phosphatidylinositol 3,5-bisphosphate.

Yeast vacuoles are acidified by the v-type H+-ATPase (V-ATPase) that is comprised of the membrane embedded VO complex and the soluble cytoplasmic V1 complex. The assembly of the V1-VO holoenzyme on the vacuole is stabilized in part through interactions between the VO a-subunit ortholog Vph1 and the lipid phosphatidylinositol 3,5-bisphosphate (PI(3,5)P2). PI(3,5)P2 also affects vacuolar Ca2+ release through the channel Yvc1 and uptake through the Ca2+ pump Pmc1. Here, we asked if H+ and Ca2+ transport activities were connected through PI(3,5)P2. We found that overproduction of PI(3,5)P2 by the hyperactive fab1T2250A mutant augmented vacuole acidification, whereas the kinase-inactive fab1EEE mutant attenuated the formation of a H+ gradient. Separately, we tested the effects of excess Ca2+ on vacuole acidification. Adding micromolar Ca2+ blocked vacuole acidification, whereas chelating Ca2+ accelerated acidification. The effect of adding Ca2+ on acidification was eliminated when the Ca2+/H+ antiporter Vcx1 was absent, indicating that the vacuolar H+ gradient can collapse during Ca2+ stress through Vcx1 activity. This, however, was independent of PI(3,5)P2, suggesting that PI(3,5)P2 plays a role in submicromolar Ca2+ flux but not under Ca2+ shock. To see if the link between Ca2+ and H+ transport was bidirectional, we examined Ca2+ transport when vacuole acidification was inhibited. We found that Ca2+ transport was inhibited by halting V-ATPase activity with Bafilomycin or neutralizing vacuolar pH with chloroquine. Together, these data show that Ca2+ transport and V-ATPase efficacy are connected but not necessarily through PI(3,5)P2.

Urinary MyProstateScore (MPS) to Rule out Clinically-Significant Cancer in Men with Equivocal (PI-RADS 3) Multiparametric MRI: Addressing an Unmet Clinical Need.

OBJECTIVE: To evaluate the complementary value of urinary MyProstateScore (MPS) testing and multiparametric MRI (mpMRI) and assess outcomes in patients with equivocal mpMRI. MATERIALS AND METHODS: Included patients underwent mpMRI followed by urine collection and prostate biopsy at the University of Michigan between 2015 -2019. MPS values were calculated from urine specimens using the validated model based on serum PSA, urinary PCA3, and urinary TMPRSS2:ERG. In the PI-RADS 3 population, the discriminative accuracy of PSA, PSAD, and MPS for GG≥2 cancer was quantified by the AUC curve. Decision curve analysis was used to assess net benefit of MPS relative to PSAD. RESULTS: There were 540 patients that underwent mpMRI and biopsy with MPS available. The prevalence of GG≥2 cancer was 13% for PI-RADS 3, 56% for PI-RADS 4, and 87% for PI-RADS 5. MPS was significantly higher in men with GG≥2 cancer [median 44.9, IQR (29.4 -57.5)] than those with negative or GG1 biopsy [median 29.2, IQR (14.8 -44.2); P <.001] in the overall population and when stratified by PI-RADS score. In the PI-RADS 3 population (n = 121), the AUC for predicting GG≥2 cancer was 0.55 for PSA, 0.62 for PSAD, and 0.73 for MPS. MPS provided the highest net clinical benefit across all pertinent threshold probabilities. CONCLUSION: In patients that underwent mpMRI and biopsy, MPS was significantly associated with GG≥2 cancer across all PI-RADS scores. In the PI-RADS 3 population, MPS significantly outperformed PSAD in ruling out GG≥2 cancer. These findings suggest a complementary role of MPS testing in patients that have undergone mpMRI.

Multiplex gene quantification as digital markers for extremely rapid evaluation of chemo-drug sensitivity.

Current administrations for precision drug uses are limited in evaluation speed. Here, we propose the use of multiplex gene-based digital markers for the extremely rapid personalized prediction of individual sensitivity to cancer drugs. We first screen the transcriptional profiles by applying two to three gene filters and scoring genes by their impact on drug sensitivity and finalize the gene lists by K-nearest neighbors cross-validation. The digital markers are cancer type dependent, are composed of tens to hundreds of gene expressions, and are rapidly quantified by reverse transcription quantitative real-time PCR (qRT-PCR) within 1-3 h after tumor sampling. The area under the receiver operating characteristic curve reached 0.88 when testing the performance of digital markers on organoids derived from colorectal cancer patient tumors. The algorithm and corresponding graphic user interface were developed to demonstrate the promise of digital markers for extremely rapid drug recommendation.

Targeted Lens Pitting to Treat Negative Dysphotopsia.

PURPOSE: To describe a patient with negative dysphotopsia who underwent a novel non-invasive technique that uses the Nd:YAG laser to induce nasal light scattering through targeted lens pitting. METHODS: Case report. RESULTS: Symptoms of negative dysphotopsia resolved after targeted lens pitting. CONCLUSIONS: Targeted lens pitting with Nd:YAG laser is a potential technique that may help treat negative dysphotopsia in a manner that preserves intraocular anatomy. Further study is warranted to explore targeted lens pitting in both patients with and without prior retinal surgery as a treatment for negative dysphotopsia. [J Refract Surg. 2021;37(3):212-214.].

The evolution of an active solitary idiopathic choroiditis (focal scleral nodule): a case report of the natural course and a review of the literature.

BACKGROUND: To describe the clinical course of an active solitary idiopathic choroiditis (focal scleral nodule) that nearly resolved over six weeks without intervention. CASE PRESENTATION: An 18-year-old man presented to the emergency department with headaches and new onset central scotoma in the right eye. Visual acuity was 20/20 in both eyes. Fundus examination revealed an amelanotic choroidal lesion with associated shallow subretinal fluid. It measured 6.1 × 6.3 × 1.4mm on A- and B-scan. Evaluation for systemic inflammatory and infectious diseases was negative. A week later, the lesion remained stable, and a month later, there was improvement of the lesion with a decrease in size on OCT and exam and resolution of the subretinal fluid suggesting that the lesion had become inactive. CONCLUSIONS: Solitary idiopathic choroiditis (Focal scleral nodule) is a rare condition characterized by inflammatory granulomatous reaction. This case report sheds light on the unknown natural course of a solitary idiopathic choroiditis (focal scleral nodule).

Fruit and vegetable consumptions in relation to frequent mental distress in breast cancer survivors.

PURPOSE: Evidence suggests that fruit and vegetable consumptions may improve mental health among general population. However, their associations among breast cancer survivors are unclear. We planned to investigate this association via a nationwide survey in the USA. METHODS: We identified 7988 breast cancer survivors from 2009 Behavioral Risk Factor Surveillance System (BRFSS). Fruit juice, fruit, and vegetable consumptions were categorized as ordinal variables to approximate tertiles. Survivors who were mentally unhealthy for at least 14 days in the past 30 days were defined as having frequent mental distress (FMD). Multivariable logistic regression treating FMD as the outcome was used to calculate adjusted odd ratios (aORs) and 95% confidence intervals (CIs) for exposures. Quadratic model was used to depict the dose-response pattern in primary analysis. Subgroup analyses by adverse lifestyle behaviors were conducted; Wald tests were used to examine if there were interactions between these factors and exposures in relation to FMD. RESULTS: Overall, 825 (10.3%) survivors had FMD. Mean age was 67.2 years, and 89.7% of survivors were white. Juice showed non-significant associations with FMD. Moderate (aOR = 0.81, 95% CI = 0.68-0.98) and high (aOR = 0.79, 95% CI = 0.63-0.98) fruit consumptions, as well as moderate vegetable consumption (aOR = 0.78, 95% CI = 0.64-0.94), were significantly and inversely associated with FMD. The dose-response curves were consistent with results in primary analysis. No interaction was identified for adverse lifestyle behaviors. CONCLUSION: Fruit and vegetable, but not fruit juice, show potential preventive effects against FMD among breast cancer survivors. The conclusion should be verified by studies with clear temporality in future.

Ovarian cancer risk in relation to blood lipid levels and hyperlipidemia: a systematic review and meta-analysis of observational epidemiologic studies.

Epidemiologic evidence regarding association of ovarian cancer risk with blood lipid level and hyperlipidemia is inconsistent. We aimed to synthesize available epidemiologic studies to disentangle associations of cholesterol, triglycerides, high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and hyperlipidemia with ovarian cancer risk. We searched PubMed, EMBASE, and Web of Science for eligible studies. A random-effects model was applied for synthesis. Heterogeneity was evaluated by a Chi-squared test for the Cochran Q statistic and the I-squared value. Subgroup analysis was conducted by design, study locale, and ovarian cancer case number. Sensitivity analysis was conducted for studies adjusting for certain covariates or with superior quality. To explore the potential dose-response relationship, we further synthesized effect measures of moderate levels of cholesterol, triglycerides, HDL-C, and LDL-C. Twelve studies (five cohort and seven case-control studies) were included. In primary meta-analysis, the synthesized risk ratio (RRpool) and 95% confidence interval (CI) suggested that high cholesterol was associated with an increased ovarian cancer risk (RRpool 1.22, 95% CI 1.01-1.48, Cochran P value: 0.40, I2: 0.5%). High HDL-C was associated with a lower ovarian cancer risk (RRpool 0.61, 95% CI 0.40-0.94, Cochran P value: 0.06, I2: 63.7%). We obtained nonsignificant associations for other exposures. Subgroup and sensitivity analyses yielded consistent results as the primary analysis. Only cholesterol showed marginally significant association in synthesis using moderate exposure levels (RRpool 1.18, 95% CI 0.99-1.42, Cochran P value: 0.51, I2: 0.0%). Our study suggests that high blood cholesterol is associated with an increased ovarian cancer risk, whereas the etiological significance of other exposures deserves more investigations.

Novel case of an adult with toxic shock syndrome following COVID-19 infection.

PURPOSE: To report a case of an adult who developed toxic shock syndrome following COVID-19 infection. OBSERVATIONS: A 28-year-old female tested positive for COVID-19. 19 days later, she developed a fever, rash and a burning sensation in both eyes. Her examination revealed mild ocular inflammation with bilateral eyelid and conjunctival involvement. Skin biopsy favored a diagnosis of toxic shock syndrome. She was initiated on corticosteroid eye drops and her ocular symptoms resolved three days later. CONCLUSION AND IMPORTANCE: Toxic shock syndrome is almost always associated with conjunctival inflammation. To our knowledge, this is the first report of an adult patient with toxic shock syndrome following COVID-19 infection. The association between toxic shock syndrome and COVID-19 is unclear; however, patients should be vigilant for symptoms as toxic shock syndrome can progress rapidly and cause multi-organ failure.

Study on the transfection efficiency of chitosan-based gene vectors modified with poly-l-arginine peptides.

Although in a series of studies, arginine peptides had shown the ability to promote the targeting delivery efficacy, the relationship between the transfection efficiency and the length of the poly-l-arginine chain had seldom been reported. This study was aimed to explore whether the chain length of poly-l-arginine grafted on chitosan had a great significance on the transfection efficiency of entering the cells. Herein, arginine and arginine peptide modified chitosan were synthesized as gene vectors (CS-Arg and CS-5Arg) and then the chemical structures were characterized by using 1 H NMR. The CS-Arg and CS-5Arg were combined with plasmids by electrostatic interactions to form stable particles. The morphology features, Zeta potentials, and buffering capacity of the complex particles were analyzed. Afterward, the combination ability with DNA and the protection ability to DNase I were studied, and the gene transfection efficiency and cellular uptake were investigated in vitro. The results showed that the gene transfection efficiency of the chitosan was significantly enhanced by arginine-graft modification. However, there were no significant differences between the CS-Arg and the CS-5Arg. The molecular simulation results indicated that the guanidine groups of grafted arginine were shielded by chitosan molecule and the guanidine groups contributed little to the gene transfection efficiency. The results demonstrated that the increased chain length of grafted arginine had no significantly enhanced effect on the transfection efficiency, which could provide convincing evidence for the construction and application of arginine and chitosan derivatives as gene vectors, and could promote the development of gene delivery system.

Antithrombotic effects of a newly purified fibrinolytic protease from Urechis unicinctus.

INTRODUCTION: The prevalence of thromboembolic disease, one of the top 3 leading causes of mortality worldwide, is being reported continually. More effective and safer antithrombotic drugs may overcome the underlying problems in antithrombotic therapy. In the present work, antithrombotic effects of UFEIII, a newly purified fibrinolytic protease from Urechis unicinctus were evaluated. MATERIALS AND METHODS: UFEIII was purified from the marine invertebrate, Urechis unicinctus, using anion exchange and gel filtration chromatography. Molecular weight, fibrinolytic activity and fibrinogenolysis pattern of UFEIII were determined. Furthermore, antithrombotic effects of UFEIII in vivo were investigated through electrical induced carotid arterial thrombosis in rats, FeCl3 induced carotid arterial thrombus model in rabbits and stasis induced vena caval thrombus model in rats. RESULTS: SDS-PAGE of the purified enzyme showed a single polypeptide chain with molecular weight of 20.8kDa. In fibrin plate assays, UFEIII could not only directly degrade fibrin but also activate plasminogen. The fibrinogenolysis pattern of UFEIII was Aα-chains>Bß-chains>γ-chain. Moreover, UFEIII could effectively prolong the time to occlusion in electrical induced carotid arterial thrombosis. Besides, both in rabbits and rats, the administration of UFEIII not only prolonged the activated partial thromboplastin time (APTT) and thrombin time (TT) also decreased the fibrinogen (FIB) content. Further, the thrombus lysis was observed after administration of UFEIII both in rabbits and rats. CONCLUSION: UFEIII can possibly be a new potential source of fibrinolytic agent.