Assessing Consistency of Respondent-driven Sampling Estimators by Using Repeated Surveys among People Who Inject Drugs (PWID) in New Jersey.

Respondent-driven sampling (RDS) is widely used to sample populations with higher risk of HIV infection for whom no sampling frames exist. However, few studies have been done to assess the consistency of RDS estimators in real world settings. We conducted an assessment study on the consistency of RDS estimators using data from the National HIV Behavioral Surveillance - People Who Inject Drugs surveys in Newark, New Jersey from 2005 to 2018. Population parameter estimates based on RDS-I, RDS-II, Gile's SS, and HCG were compared longitudinally and cross-sectionally. Population homophily statistics and differential recruitment statistics were estimated and compared. Convergence plots were used for RDS diagnosis. Sensitivity analyses were conducted on population size estimates and seeds biases. By comparing time-insensitive population parameters and population homophily statistics estimated by four RDS estimators, the study found that RDS-II and Gile's SS could provide longitudinally and cross-sectionally consistent estimates and population homophily statistics on gender and sexual orientation. Cross-sectional comparison of time-sensitive population parameter estimates also supported the consistency of RDS-II and Gile's SS. However, RDS-I and HCG did not perform well in those comparisons. In conclusion, RDS estimators may not address all inconsistencies, but RDS-II and Gile's SS are recommended to weight RDS samples given enough consistency was observed in them.

HIV and hepatitis B, C co-infection and correlates of HIV infection among men who have sex with men in Rwanda, 2021: a respondent-driven sampling, cross-sectional study.

BACKGROUND: Men who have sex with men (MSM) are a key population group disproportionately affected by HIV and other sexually transmitted infections (STIs) worldwide. In Rwanda, the HIV epidemic remains a significant public health concern, and understanding the burden of HIV and hepatitis B and C coinfections among MSM is crucial for designing effective prevention and control strategies. This study aims to determine the prevalence of HIV, hepatitis B, and hepatitis C infections among MSM in Rwanda and identify correlates associated with HIV infection within this population. METHODS: We used respondent-driven sampling (RDS) to recruit participants between November and December 2021. A face-to-face, structured questionnaire was administered. Testing for HIV infection followed the national algorithm using two rapid tests: Alere Combo and STAT PAK as the first and second screening tests, respectively. Hepatitis B surface antigen (HBsAg) and anti-HCV tests were performed. All statistics were adjusted for RDS design, and a multivariable logistic regression model was constructed to identify factors associated with HIV infection. RESULTS: The prevalence of HIV among MSM was 6·9% (95% CI: 5·5-8·6), and among HIV-positive MSM, 12·9% (95% CI: 5·5-27·3) were recently infected. The prevalence of hepatitis B and C was 4·2% (95% CI: 3·0-5·7) and 0·7% (95% CI: 0·4-1·2), respectively. HIV and hepatitis B virus coinfection was 0·5% (95% CI: 0·2-1·1), whereas HIV and hepatitis C coinfection was 0·1% (95% CI: 0·0-0·5), and no coinfection for all three viruses was observed. MSM groups with an increased risk of HIV infection included those who ever suffered violence or abuse because of having sex with other men (AOR: 3·42; 95% CI: 1·87-6·25), those who refused to answer the question asking about 'ever been paid money, goods, or services for sex' (AOR: 10·4; 95% CI: 3·30-32·84), and those not consistently using condoms (AOR: 3·15; 95% CI: 1·31-7·60). CONCLUSION: The findings suggest more targeted prevention and treatment approaches and underscore the importance of addressing structural and behavioral factors contributing to HIV vulnerability, setting interventions to reduce violence and abuse against MSM, promoting safe and consensual sexual practices, and expanding access to HIV prevention tools such as condoms and preexposure prophylaxis (PrEP).

FDA's stamp of approval: Unveiling peptide breakthroughs in cardiovascular diseases, ACE, HIV, CNS, and beyond.

Peptides exhibit significant specificity and effective interaction with therapeutic targets, positioning themselves as key players in the global pharmaceutical market. They offer potential treatments for a wide range of diseases, including those that pose significant challenges. Notably, the peptide trofinetide (Daybue) marked a groundbreaking achievement by providing the first-ever cure for Rett syndrome, and several peptides have secured FDA approval as first-in-class medications. Furthermore, peptides are expanding their presence in areas traditionally dominated by either small or large molecules. A noteworthy example is the FDA approval of motixafortide (Aphexda) as the first peptide-based chemokine antagonist. Here, the focus will be on the analysis of FDA-approved peptides, particularly those targeting cardiovascular diseases, human immunodeficiency, central nervous system diseases, and various other intriguing classes addressing conditions such as osteoporosis, thrombocytopenia, Cushing's disease, and hypoglycemia, among others. The review will explore the chemical structures of the peptides, their indications and modes of action, the developmental trajectory, and potential adverse effects.

Determinants of depressive and alcohol use disorders among female sex workers in Ethiopia: evidence from a national bio-behavioral survey, 2020.

BACKGROUND: Female sex workers (FSWs) face an elevated risk of developing mental health disorders and alcohol use disorders (AUD), which in turn increase their vulnerability to HIV and other sexually transmitted infections (STIs) and other negative outcomes. To effectively address both of these health issues, it is crucial to understand the shared key determinants underlying these illnesses, which is a substantial knowledge gap in Ethiopia and elsewhere in the world. Therefore, this study aimed to identify the common key determinants of depression and AUD among FSWs in Ethiopia using a bivariate multivariable ordinal logistic model. METHODS: We analyzed cross-sectional biobehavioral data collected in 2020 from 16 cities and major towns in Ethiopia using the respondent-driven sampling (RDS) technique, which involved a total of 6,085 FSWs. FSWs who had lived at the study sites for at least a month before the study period were deemed eligible for recruitment. Major depressive disorder (DD) and AUD were screened using the Patient Health Questionnaire (PHQ9) and alcohol use disorder identification test (AUDIT), respectively. We used descriptive statistics to summarize study population characteristics and bivariate multivariable ordinal logistic regression (BMOLR) to identify common determinants of DD and AUD combined and their nonnormal correlation. RESULTS: Among 6085 FSWs screened for DD and AUD, 13.5% and 4.0% have met the criteria for moderate and severe depressive disorder, respectively, and 20.3% and 34.7% have met the AUDIT criteria for harmful or hazardous behavior and alcohol dependence, respectively. FSW with experience of inconsistent condom use, condom failure, violence, mobility, use of any drugs, non-paying partners, abortion, and selling sex for more than five years were associated with an increase in the severity of both disorders. A high average income from selling sex and the number of paying partners reduced the severity of depression and increased the level of alcohol dependence. Being HIV positive and ever having anal sex were associated only with an increase in depression. CONCLUSION: Major DD and AUD are prevalent among FSWs in Ethiopia. The findings revealed that common key determinants, which exacerbated the severity of both disorders, were also risk factors for HIV and other STIs. Consequently, integrated STI strategies are essential in the screening, referral, and treatment of depression and AUD. Intervention packages should encompass determinants of depression and AUD, including condom utilization, drug use, mobility between towns, abortion, violence, and counseling services. Additionally, strategies to ensure economic security should be incorporated.

Association between in-country migration and HIV infection among transgender women from northeastern Brazil: a respondent-driven sampling survey.

BACKGROUND: Migration is common among transgender women (TGW), often driven by the desire to escape stigma, find acceptance, establish new connections, access body modifications, or enter new avenues of sex work. Given the heightened mobility of TGW, they are mostly vulnerable to human immunodeficiency virus (HIV) due to migration. This study aimed to evaluate the association between in-country migration and HIV infection among TGW in Northeast Brazil. METHODS: The DIVAS was a cross-sectional, multicity study investigating risk behaviors and sexually transmitted infections (STI) among TGW in 2016-2017. A total of 864 TGW were recruited through respondent-driven sampling from three capital cities in Northeast Brazil. Logistic regression estimating odds ratios (OR) and 95% confidence intervals (CI) was used to assess the relationship between in-country migration and HIV infection. RESULTS: The prevalence of HIV among TGW was 24.5%, 21.4% among those aged 18-34 and 36.1% among those ≥ 35 years old. In-country migration increased the odds of HIV infection among TGW aged 18-34 years (OR = 1.84; 95%CI:1.04-3.27) and even higher among those aged ≥ 35y old (OR = 3.08; 95%CI:1.18-8.04). CONCLUSIONS: These data reinforce the pressing need for public health policies that provide comprehensive access and strategies for demand creation for HIV/AIDS prevention and care for TGW who are already highly vulnerable to infection.

Stereotactic radiotherapy of intracranial tumor beds on a ring-mounted Halcyon LINAC.

PURPOSE: This study sought to evaluate the feasibility and efficacy of the Halcyon Ring Delivery System (RDS) for delivering stereotactic radiotherapy (SRT) treatments for intracranial tumors beds. METHODS: Ten previously treated brain SRT patients for 30 Gy in five fractions with non-coplanar HyperArc plans on TrueBeam (6MV-FFF) were replanned on Halcyon (6MV-FFF) using the same number of arcs and Eclipse's AcurosXB dose engine. Plan quality evaluation metrics per SRT protocol included: PTV coverage, GTV dose (minimum and mean), target conformity indices (CI), heterogeneity index (HI), gradient index (GI), maximum dose 2 cm away from the PTV (D2cm), and doses to organs-at-risk (OAR). Additionally, patient-specific quality assurance (QA) results and beam-on-time (BOT) were analyzed. RESULTS: The Halcyon RDS provided highly conformal SRT plans for intracranial tumor beds with similar dose to target. When benchmarked against clinically delivered HyperArc plans, target coverage, CI(s) and HI were statistically similar. The Halcyon plans saw no statistical difference in maximum OAR doses to the brainstem, spinal cord, and cochlea. Due to the machine's coplanar geometry, the Halcyon plans showed a decrease in optic pathway dose (0.75 Gy vs. 2.08 Gy, p = 0.029). Overall, Halcyon's coplanar geometry resulted in a larger GI (3.33 vs. 2.72, p = 0.008) and a larger D2cm (39.59% vs. 29.07%, p < 0.001). In this cohort, multiple cases had the PTV and the optic pathway in the same axial plane. In one such instance, the PTV was <2 cm away from the optic pathway but even at this close proximity OAR, Halcyon still adequately spared the optic pathway. Additionally, the Halcyon's geometry provided slightly larger amount of normal brain dose receiving 24.4 Gy (8.99 cc vs. 7.36 cc) and 28.8 Gy (2.9 cc vs. 2.5 cc), although statistically insignificant. The Halcyon plans achieved similar delivery accuracy, quantified by patient-specific QA results evaluated with a 2%/2 mm gamma criteria (99.42% vs. 99.70%). For both plans, independent Monte Carlo second checks calculation agreed within 1%. Average Halcyon BOT was slightly higher by 0.35 min (p = 0.045), however, due to the one-step patient set-up and verification overall estimated treatment times on Halcyon were lower compared to HyperArc treatments (7.61 min vs. 10.26 min, p < 0.001). CONCLUSIONS: When benchmarked against clinically delivered HyperArc treatments, the Halcyon brain SRT plans provided similar plan quality and delivery accuracy but achieved faster overall treatment times. We have started treating select brain SRT patients on the Halcyon RDS for patients having tumor beds greater than 1 cm in diameter with the closest OAR distance of greater than 2 cm away from the target. We recommend other clinics to consider commissioning SRT treatments on their Halcyon systems-allowing including remote Halcyon-only clinics to provide exceptionally high-quality therapeutic brain SRT treatments to an otherwise underserved patient cohort.

Research Progress on Router Devices for the OAM Optical Communication.

Vortex beams carrying orbital angular momentum (OAM) provide a new degree of freedom for light waves in addition to the traditional degrees of freedom, such as intensity, phase, frequency, time, and polarization. Due to the theoretically unlimited orthogonal states, the physical dimension of OAM is capable of addressing the problem of low information capacity. With the advancement of the OAM optical communication technology, OAM router devices (OAM-RDs) have played a key role in significantly improving the flexibility and practicability of communication systems. In this review, major breakthroughs in the OAM-RDs are summarized, and the latest technological standing is examined. Additionally, a detailed account of the recent works published on techniques related to the OAM-RDs has been categorized into five areas: channel multicasting, channel switching, channel filtering, channel hopping, and channel adding/extracting. Meanwhile, the principles, research methods, advantages, and disadvantages are discussed and summarized in depth while analyzing the future development trends and prospects of the OAM-RDs.

Descriptive and Functional Genomics in Neonatal Respiratory Distress Syndrome: From Lung Development to Targeted Therapies.

In this up-to-date study, we first aimed to highlight the genetic and non-genetic factors associated with respiratory distress syndrome (RDS) while also focusing on the genomic aspect of this condition. Secondly, we discuss the treatment options and the progressing therapies based on RNAs or gene therapy. To fulfill this, our study commences with lung organogenesis, a highly orchestrated procedure guided by an intricate network of conserved signaling pathways that ultimately oversee the processes of patterning, growth, and differentiation. Then, our review focuses on the molecular mechanisms contributing to both normal and abnormal lung growth and development and underscores the connections between genetic and non-genetic factors linked to neonatal RDS, with a particular emphasis on the genomic aspects of this condition and their implications for treatment choices and the advancing therapeutic approaches centered around RNAs or gene therapy.

Telephone Outreach Enhances Recruitment of Underrepresented Seriously Ill Patients for an Advance Care Planning Pragmatic Trial.

BACKGROUND: Patients experiencing systemic patterns of disadvantage, such as racial/ethnic minorities and those with limited English proficiency, are underrepresented in research. This is particularly true for large pragmatic trials of potentially sensitive research topics, such as advance care planning (ACP). It is unclear how phone outreach may affect research participation by underrepresented individuals. OBJECTIVE: To assess the effect of phone outreach, in addition to standard mail survey recruitment, in a population-based ACP pragmatic trial at three academic health systems in California. DESIGN: Retrospective cohort study PATIENTS: Primary care patients with serious illness were mailed a survey in their preferred language. Patients who did not initially respond by mail received up to three reminder phone calls with the option of survey completion by phone. MAIN MEASURES: Effect of phone outreach on survey response rate associated with respondent demographic characteristics (e.g., Social Vulnerability Index [SVI], range 0 (low) to 1 (high)). RESULTS: Across the health systems, 5998 seriously ill patients were mailed surveys. We obtained completed surveys from 1215 patients (20% response rate); 787 (65%) responded after mail alone and 428 (35%) participated only after phone outreach. Patients recruited after phone outreach compared to mail alone were more socially vulnerable (SVI 0.41 v 0.35, P < 0.001), were more likely to report being a racial/ethnic minority (35% v 28%, P = 0.006), and non-English speaking (16% v 10%, P = 0.005). Age and gender did not differ significantly. The inclusion of phone outreach resulted in a sample that better represented the baseline population than mail alone in racial/ethnic minority (28% mail alone, 30% including phone outreach, 36% baseline population), non-English language preference (10%, 12%, 15%, respectively), and SVI (0.35, 0.37, 0.38, respectively). CONCLUSIONS: Phone outreach for a population-based survey in a pragmatic trial concerning a potentially sensitive topic significantly enhanced recruitment of underrepresented seriously ill patients.

Hepatitis C virus prevalence among men who have sex with men: a cross-sectional study in 12 Brazilian cities.

BACKGROUND: Despite the preventive policies adopted, reduction in sexually transmitted infections (STIs) among men who have sex with men (MSM) has been limited. The risk of hepatitis C virus (HCV) infection has increased among the most vulnerable population groups, including MSM. The aim of this study was to estimate the prevalence of HCV infection and to assess risky practices among MSM from 12 Brazilian cities. METHODS: This study was carried out from June to December 2016 using respondent driven sampling (RDS). Participants completed a self-administered questionnaire to collect behavioral, socioeconomic, and demographic variables. In addition, the rapid diagnostic test (RDT) for HCV was offered. Positive results were sent to Instituto Adolfo Lutz for confirmation. RESULTS: A total of 4,176 participants were recruited and 23 samples were sent for confirmation. Of these, 16 were confirmed, resulting in a prevalence of 0.7% (95% CI: 0.3%-1.7%). The Southeast region showed a prevalence of 0.9% (95% CI: 0.3-2.6), followed by the South region, with 0.6% (95% CI: 0.2-2.1). The Northeast region had a prevalence of 0.3% (95% CI: 0.1-1.0) and the Midwest 0.1% (95% CI: 0.0-0.7). No positive cases were found in the North. Single men aged 40 years or older were the majority of participants exposed to HCV. High levels of alcohol consumption, illicit drug use, irregular condom use, in addition to infection with other STIs, were associated with exposure to HCV. CONCLUSIONS: STIs continue to be important health problems in Brazil and globally. Many STIs are inapparent for many years until they bring more serious consequences. Extra investment in HCV is also warranted, given that it can be eliminated. Relying solely on clinical data to provide information about inapparent infection, especially in stigmatized populations, will make that goal more difficult to achieve. Surveillance studies, such as the one reported here need to be repeated over time to demonstrate trends and to provide information for evaluation, program and policies. Investments in the most vulnerable populations are critical to achieve the World Health Organization global health goals including the elimination of viral hepatitis by 2030.

HIV prevalence and associated risk factors among young tertiary student men who have sex with men (MSM) in Nairobi, Kenya: a respondent-driven sampling survey.

BACKGROUND: Young men who have sex with men (MSM), are a key population at higher risk of HIV infection yet they are underrepresented in research. We conducted a bio-behavioral survey to estimate HIV prevalence and associated risk factors among tertiary student MSM (TSMSM) in Nairobi, Kenya. METHODS: Between February and March 2021, 248 TSMSM aged ≥ 18 years who reported sex with another man in the past year participated in a respondent-driven sampling (RDS) based cross-sectional survey. Participants completed an electronically self-administered behavioral survey and provided a blood sample for HIV antibody testing, alongside urine, anorectal and oropharyngeal swabs for pooled testing of sexually transmitted infections using a multiplex nucleic acid amplification test. RDS-Analyst v.0.72 and Stata v.15 software were used for data analysis. Differences in proportions were examined using chi-square (χ2) test, and unweighted multivariate logistic regression was used to assess factors associated with HIV infection. RESULTS: HIV prevalence among study participants was 8.3%, whereas the weighted prevalence was 3.6% (95% CI: 1.3-6.0%). Median ages of participants, and at self-reported first anal sex with a man were 21(interquartile range [IQR] 20-22) and 18 (IQR 17-19) years, respectively. A majority (89.3%) of TSMSM owned a smart phone, 46.5% had ever used a geosocial networking app for MSM such as Grindr ® to find a sex partner, and a third (33.6%) met their last sex partner online.  Almost three-quarters (71.3%) had > 1 male sex partner in the year before the survey. A third (34.3%) did not use condoms with their last sex partner, 21.2% received money from their last sex partner and 40.9% had taken alcohol/another drug during their last sexual encounter. HIV infection was associated with studying in private institutions (adjusted odds ratio[AOR] = 6.0; 95% confidence intervals [CI] : 1.2-30.0, p = 0.027), preferring a sex partner of any age-younger, same or older (AOR = 5.2; 95 CI: 1.1-25.2, p = 0.041), last sex partner being > 25 years (AOR = 6.4; 95% CI: 1.2-34.6, p = 0.030), meeting the last sex partner online (AOR = 4.2; 95% CI; 1.1-17.0, p = 0.043) and testing positive for Neisseria gonorrhea (AOR = 7.8; 95% CI: 2.0-29.9, p = 0.003). CONCLUSIONS: HIV prevalence among TSMSM in Nairobi is alarmingly high, demonstrating a need for tailored prevention and control interventions for this young key population.

Limited awareness of HIV Status hinders uptake of treatment among female sex workers and sexually exploited adolescents in Wau and Yambio, South Sudan.

BACKGROUND: Several factors determine uptake of HIV testing services (HTS) by female sex workers (FSW), including their knowledge of HIV and their awareness of services supporting people who are HIV-positive. HTS provided entry into the UNAIDS 90-90-90 cascade of care. We conducted a cross-sectional biobehavioural survey (BBS) to determine HIV prevalence and progress towards UNAIDS 90-90-90 cascade targets among this population in South Sudan. METHODS: Respondent-driven sampling (RDS) was used to recruit women and sexually exploited girls aged 13-18 years who exchanged sex for goods or money in the past 6 months and resided in the town for at least 1 month. Consenting participants were interviewed and tested for HIV and, if positive, they were also tested for their viral load (VL). Data were weighted in RDS Analyst and analyzed with Stata 13. RESULTS: A total of 1,284 participants were recruited. The overall HIV cascade coverages were 64.8% aware of their HIV-positive status; 91.0% of those aware of their positive status were on ART; and VL suppression among those on ART was 93.0%. CONCLUSION: Being unaware of their HIV-positive status limits, the uptake of HIV treatment among FSW in South Sudan. This underscores the importance of optimized case-finding approaches to increase HTS among FSW and sexually exploited minors.

Mobility and HIV vulnerabilities among female sex workers in Guinea-Bissau: findings from an integrated bio-behavioral survey.

BACKGROUND: Mobility is an important risk determinant for HIV given the potential for intermittent access to HIV services. Mobility may be particularly relevant among female sex workers, (FSW) who have been shown to be at high risk for HIV in settings around the world. Data regarding the role mobility plays in exacerbating HIV risks among FSW across Sub-Saharan Africa remains limited, and data on FSW in Guinea-Bissau is sparse. METHODS: FSW in four regions of Guinea-Bissau were recruited with a respondent-driven sampling (RDS) method and participated in an integrated bio-behavioral survey between September 27, 2017 and January 26, 2018. Associations between reported general mobility, mobility to or residence in Bissau, and social and HIV vulnerabilities among FSW in Guinea-Bissau were assessed using multivariable logistic regression models. Population proportions were weighted for RDS sampling, while logistic regression models were not. RESULTS: Survey respondents included 323 individuals in Bissau, 45 in Bissorã, 140 in Bafatá, and 59 in Gabu. Statistical analyses demonstrated that mobility to more than one destination was significantly associated with recent sex without a condom (ie, sex without a condom within the last three sex acts) with both clients (aOR: 2.47 (95% CI: 1.08, 5.64)) and non-paying partners (aOR: 5.39 (95% CI: 2.61, 11.15)) compared to non-mobility. However, mobility to one or more locations was also associated with higher odds of receiving HIV prevention information, and mobility to more than one location was associated with participating in programming with HIV-related organizations. CONCLUSIONS: These results suggest that while some prevention services including HIV prevention information reach mobile FSW in Guinea-Bissau more than their non-mobile counterparts, the higher rates of condomless sex among mobile FSW suggest that HIV prevention needs may remain unmet for mobile FSW in Guinea-Bissau. Additionally, the results suggest a nuanced relationship between mobility, place of residence, and HIV and social vulnerabilities and prevention indicators.

A multicentre neonatal interventional randomised controlled trial of nebulized surfactant for preterm infants with respiratory distress: Neo-INSPIRe trial protocol.

INTRODUCTION: Respiratory distress syndrome in preterm infants is an important cause of morbidity and mortality. Less invasive methods of surfactant administration, along with the use of continuous positive airway pressure (CPAP), have improved outcomes of preterm infants. Aerosolized surfactant can be given without the need for airway instrumentation and may be employed in areas where these skills are scarce. Recent trials from high-resourced countries utilising aerosolized surfactant have had a low quality of evidence and varying outcomes. METHODS AND ANALYSIS: The Neo-INSPIRe trial is an unblinded, multicentre, randomised trial of a novel aerosolized surfactant drug/device combination. Inclusion criteria include preterm infants of 27-34+6 weeks' gestational age who weigh 900-1999g and who require CPAP with a fraction of inspired oxygen (FiO2) of 0.25-0.35 in the first 2-24 h of age. Infants are randomised 1:1 to control (CPAP alone) or intervention (CPAP with aerosolized surfactant). The primary outcome is the need for intratracheal bolus surfactant instillation within 72 h of age. Secondary outcomes include the incidence of reaching failure criteria (persistent FiO2 of > 0.40, severe apnoea or severe work of breathing), the need for and duration of ventilation and respiratory support, bronchopulmonary dysplasia and selected co-morbidities of prematurity. Assuming a 40% relative risk reduction to reduce the proportion of infants requiring intratracheal bolus surfactant from 45 to 27%, the study will aim to enrol 232 infants for the study to have a power of 80% to detect a significant difference with a type 1 error of 0.05. ETHICS AND DISSEMINATION: Ethical approval has been granted by the relevant human research ethics committees at University of Cape Town (HREC 681/2022), University of the Witwatersrand HREC (221112) and Stellenbosch University (M23/02/004). TRIAL REGISTRATION: PACTR202307490670785.

Prime Editing Strategy to Install the PRPH2 c.828+1G>A Mutation.

Mutations in peripherin 2 (PRPH2) are associated with a spectrum of inherited retinal diseases (IRDs) including retinitis pigmentosa (RP) and macular degeneration. As PRPH2 is localized to cone and rod outer segments, mutations in PRPH2 lead the disorganization or absence of photoreceptor outer segments. Here, we report on a patient with PRPH2-linked RP who exhibited widespread RPE atrophy with a central area of macular atrophy sparing the fovea. In future studies, we plan to model the pathobiology of PRPH2-based RP using induced pluripotent stem cell (iPSC)-derived retinal organoids. To effectively model rare mutations using iPSC-derived retinal organoids, we first require a strategy that can install the desired mutation in healthy wild-type iPSC, which can efficiently generate well-laminated retinal organoids. In this study, we developed an efficient prime editing strategy for the installation of the pathogenic PRPH2 c.828+1 G>A splice-site mutation underlying our patient's disease.

The Role of Peripherin-2/ROM1 Complexes in Photoreceptor Outer Segment Disc Morphogenesis.

The light-sensitive outer segment organelle of photoreceptor cells contains a stack of hundreds of flat, disc-shaped membranes called discs. The rims of these discs contain a photoreceptor-specific tetraspanin protein peripherin-2 (also known as rds or PRPH2). Mutations in the PRPH2 gene lead to a wide variety of inherited retinal degenerations in humans. The vast majority of these mutations occur within a large, intradiscal loop of peripherin-2, known as the D2 loop. The D2 loop mediates well-established intermolecular interactions of peripherin-2 molecules among themselves and a homologous protein ROM1. These interactions lead to the formation of large, highly ordered oligomers. In this chapter, we discuss the supramolecular organization of peripherin-2/ROM1 complexes and their contribution to the process of outer segment disc morphogenesis and enclosure.

Benchmarking halcyon ring delivery system for hypofractionated breast radiotherapy: Validation and clinical implementation of the fast-forward trial.

PURPOSE: The aim of this study was to demonstrate the feasibility and efficacy of an iterative CBCT-guided breast radiotherapy with Fast-Forward trial of 26 Gy in five fractions on a Halcyon Linac. This study quantifies Halcyon plan quality, treatment delivery accuracy and efficacy by comparison with those of clinical TrueBeam plans. MATERIALS AND METHODS: Ten accelerated partial breast irradiation (APBI) patients (four right, six left) who underwent Fast-Forward trial at our institute on TrueBeam (6MV beam) were re-planned on Halcyon (6MV-FFF). Three site-specific partial coplanar VMAT arcs and an Acuros-based dose engine were used. For benchmarking, PTV coverage, organs-at-risk (OAR) doses, beam-on time, and quality assurance (QA) results were compared for both plans. RESULTS: The average PTV was 806 cc. Compared to TrueBeam plans, Halcyon provided highly conformal and homogeneous plans with similar mean PTVD95 (25.72  vs. 25.73 Gy), both global maximum hotspot < 110% (p = 0.954) and similar mean GTV dose (27.04  vs. 26.80 Gy, p = 0.093). Halcyon provided lower volume of ipsilateral lung receiving 8 Gy (6.34% vs. 8.18%, p = 0.021), similar heart V1.5 Gy (16.75% vs. 16.92%, p = 0.872), V7Gy (0% vs. 0%), mean heart dose (0.96  vs. 0.9 Gy, p = 0.228), lower maximum dose to contralateral breast (3.2  vs. 3.6 Gy, p = 0.174), and nipple (19.6  vs. 20.1 Gy, p = 0.363). Compared to TrueBeam, Halcyon plans provided similar patient-specific QA pass rates and independent in-house Monte Carlo second check results of 99.6% vs. 97.9% (3%/2 mm gamma criteria) and 98.6% versus 99.2%, respectively, suggesting similar treatment delivery accuracy. Halcyon provided shorter beam-on time (1.49  vs. 1.68 min, p = 0.036). CONCLUSION: Compared to the SBRT-dedicated TrueBeam, Halcyon VMAT plans provided similar plan quality and treatment delivery accuracy, yet potentially faster treatment via one-step patient setup and verification with no patient collision issues. Rapid delivery of daily APBI on Fast-Forward trial on Halcyon with door-to-door patient time < 10 min, could reduce intrafraction motion errors, and improve patient comfort and compliance. We have started treating APBI on Halcyon. Clinical follow-up results are warranted. We recommend Halcyon users consider implementing the protocol to remote and underserved APBI patients in Halcyon-only clinics.

How much rotational error is clinically acceptable for single-isocenter/two-lesion lung SBRT treatment on halcyon ring delivery system (RDS)?

PURPOSE: SBRT treatment of two separate lung lesions via single-isocenter/multi-target (SIMT) plan on Halcyon RDS could improve patient comfort, compliance, patient throughput, and clinic efficiency. However, aligning two separate lung lesions synchronously via a single pre-treatment CBCT scan on Halcyon can be difficult due to rotational patient setup errors. Thus, to quantify the dosimetric impact, we simulated loss of target(s) coverage due to small, yet clinically observable rotational patient setup errors on Halcyon for SIMT treatments. METHODS: Seventeen previously treated 4D-CT based SIMT lung SBRT patients with two separate lesions (total 34 lesions, 50 Gy in five fractions to each lesion) on TrueBeam (6MV-FFF) were re-planned on Halcyon (6MV-FFF) using a similar arc geometry (except couch rotation), dose engine (AcurosXB algorithm), and treatment planning objectives. Rotational patient setup errors of [± 0.5° to ± 3.0°] on Halcyon were simulated via Velocity registration software in all three rotation axes and recalculated dose distributions in Eclipse treatment planning system. Dosimetric impact of rotational errors was evaluated for target coverage and organs at risk (OAR). RESULTS: Average PTV volume and distance to isocenter were 23.7 cc and 6.1 cm. Average change in Paddick's conformity indexes were less than -5%, -10%, and -15% for 1°, 2°, and 3°, respectively for yaw, roll, and pitch rotation directions. Maximum drop off of PTV(D100%) coverage for 2° rotation was -2.0% (yaw), -2.2% (roll), and -2.5% (pitch). With ±1° rotational error, no PTV(D100%) loss was found. Due to anatomical complexity: irregular and highly variable tumor sizes and locations, highly heterogenous dose distribution, and steep dose gradient, no trend for loss of target(s) coverage as a function of distance to isocenter and PTV size was found. Change in maximum dose to OAR were acceptable per NRG-BR001 within ±1.0° rotation, but were up to 5 Gy higher to heart with 2° in the pitch rotation axis. CONCLUSION: Our clinically realistic simulation results show that rotational patient setup errors up to 1.0° in any rotation axis could be acceptable for selected two separate lung lesions SBRT patients on Halcyon. Multivariable data analysis in large cohort is ongoing to fully characterize Halcyon RDS for synchronous SIMT lung SBRT.

Five Year Analyses of Vegetation Response to Restoration using Rock Detention Structures in Southeastern Arizona, United States.

Rock detention structures (RDS) are used in restoration of riparian areas around the world. The purpose of this study was to analyze the effect of RDS installation on vegetation in terms of species abundance and composition. We present the results from 5 years of annual vegetation sampling which focused on short term non-woody vegetation response within the riparian channel at 3 restoration sites across southeastern Arizona. We examined the potential ways that RDS can preserve native species, encourage wetland species, and/or introduce nonnative species using a Control-Impact-Paired-Series study design. Species composition and frequency were measured within quadrats and zones on an annual basis. Multivariate bootstrap analyses were performed, including Bray-Curtis dissimilarity index and non-metric multidimensional scaling ordination. We found that response to RDS was variable and could be related to the level of degradation or proximity to groundwater. The non-degraded site did not show a response to RDS and the severely degraded site showed a slight increase in vegetation frequency, but the moderately degraded site experienced a significant increase. At the moderately degraded site, located between two historic ciénegas (desert wetlands), species composition shifted and nonnative species invaded, dominating the vegetation increase at this location. At the severely degraded site, pre-existing wetland species frequency increased in response to the installation of RDS. These findings extend the understanding of RDS effects on vegetation, provide scenarios to help land and water resource managers understand potential outcomes, and can assist in optimizing success for restoration projects.

Efficacy, dose-response, and aerosol delivery of dry powder synthetic lung surfactant treatment in surfactant-deficient rabbits and premature lambs.

BACKGROUND: Dry powder (DP) synthetic lung surfactant may be an effective means of noninvasive delivery of surfactant therapy to premature infants supported with nasal continuous positive airway pressure (nCPAP) in low-resource settings. METHODS: Four experimental DP surfactant formulations consisting of 70% of phospholipids (DPPC:POPG 7:3), 3% Super Mini-B (SMB) or its sulfur-free derivate B-YL as SP-B peptide mimic, 25% of lactose or trehalose as excipient, and 2% of NaCl were formulated using spray drying. In vitro surface activity was confirmed with captive bubble surfactometry. Surfactant particle size was determined with a cascade impactor and inhaled dose was quantified using a spontaneously breathing premature lamb lung model supported with CPAP. In vivo surfactant efficacy was demonstrated in three studies. First, oxygenation and lung compliance were monitored after intratracheal instillation of resuspended DP surfactant in intubated, ventilated, lavaged, surfactant-deficient juvenile rabbits. In dose-response studies, ventilated, lavaged, surfactant-deficient rabbits received 30, 60, 120 or 240 mg/kg of DP B-YL:Lactose or B-YL:Trehalose surfactant by aerosol delivery with a low flow aerosol chamber via their endotracheal tube. Noninvasive aerosolization of DP B-YL:Trehalose surfactant via nasal prongs was tested in spontaneous breathing premature lambs supported with nCPAP. Intratracheal administration of 200 mg/kg of Curosurf®, a liquid porcine surfactant, was used as a positive control. RESULTS: Mass median aerosol diameter was 3.6 µm with a geometric standard deviation of 1.8. All four experimental surfactants demonstrated high surface efficacy of intratracheal instillation of a bolus of ~ 100 mg/kg of surfactant with improvement of oxygenation and lung compliance. In the dose-response studies, rabbits received incremental doses of DP B-YL:Lactose or B-YL:Trehalose surfactant intratracheally and showed an optimal response in oxygenation and lung function at a dose of 120-240 mg/kg. Aerosol delivery via nasal prongs of 1 or 2 doses of ~ 100 mg/kg of B-YL:Trehalose surfactant to premature lambs supported with nCPAP resulted in stabilization of spontaneous breathing and oxygenation and lung volumes comparable to the positive control. CONCLUSION: These studies confirm the clinical potential of DP synthetic lung surfactant with B-YL peptide as a SP-B mimic to alleviate surfactant deficiency when delivered as a liquid bolus or as an aerosol.