Potential of DPD ((S)-4,5-dihydroxy-2,3-pentanedione) Analogs in Microparticulate Formulation as Vaccine Adjuvants.

The molecule (S)-4,5-dihydroxy-2,3-pentanedione (DPD) is produced by many different species of bacteria and is involved in bacterial communication. DPD is the precursor of signal molecule autoinducer-2 (AI-2) and has high potential to be used as a vaccine adjuvant. Vaccine adjuvants are compounds that enhance the stability and immunogenicity of vaccine antigens, modulate efficacy, and increase the immune response to a particular antigen. Previously, the microparticulate form of (S)-DPD was found to have an adjuvant effect with the gonorrhea vaccine. In this study, we evaluated the immunogenicity and adjuvanticity of several synthetic analogs of the (S)-DPD molecule, including ent-DPD((R)-4,5-dihydroxy-2,3-pentanedione), n-butyl-DPD ((S)-1,2-dihydroxy-3,4-octanedione), isobutyl-DPD ((S)-1,2-dihydroxy-6-methyl-3,4-heptanedione), n-hexyl-DPD ((S)-1,2-dihydroxy-3,4-decanedione), and phenyl-DPD ((S)-3,4-dihydroxy-1-phenyl-1,2-butanedione), in microparticulate formulations. The microparticulate formulations of all analogs of (S)-DPD were found to be noncytotoxic toward dendritic cells. Among these analogs, ent-DPD, n-butyl-DPD, and isobutyl-DPD were found to be immunogenic toward antigens and showed adjuvant efficacy with microparticulate gonorrhea vaccines. It was observed that n-hexyl-DPD and phenyl-DPD did not show any adjuvant effect. This study shows that synthetic analogs of (S)-DPD molecules are capable of eliciting adjuvant effects with vaccines. A future in vivo evaluation will further confirm that these analogs are promising vaccine adjuvants.

Guillain Barre syndrome mimicking brain death.

A 49-year-old female patient presented at the hospital with a history of herpetic blisters, frequent episodes of vomiting and loose stools, bilateral upper and lower limb weakness, and diminishing sensorium. She was diagnosed with hyponatraemia and respiratory failure and later became unconscious with absent brainstem reflexes. The patient was initially treated for herpetic encephalitis, a chronic obstructive pulmonary disease with acute exacerbation, hyponatraemia and neuroparalytic snake bite. Further evaluation, however, identified the uncommon Guillain Barre syndrome presentation with overlap of Bickerstaff brainstem encephalitis. This is an uncommon disorder characterised by the involvement of higher mental functions, fixed dilated pupils, absent brainstem reflexes and quadriplegia that resembles a neuroparalytic snake bite and brain death. After receiving intravenous immunoglobulins for treatment, the patient completely recovered.

Three-dimensional electro-neural interfaces electroplated on subretinal prostheses.

Objective.Retinal prosthetics offer partial restoration of sight to patients blinded by retinal degenerative diseases through electrical stimulation of the remaining neurons. Decreasing the pixel size enables increasing prosthetic visual acuity, as demonstrated in animal models of retinal degeneration. However, scaling down the size of planar pixels is limited by the reduced penetration depth of the electric field in tissue. We investigated 3-dimensional (3d) structures on top of photovoltaic arrays for enhanced penetration of the electric field, permitting higher resolution implants.Approach.3D COMSOL models of subretinal photovoltaic arrays were developed to accurately quantify the electrodynamics during stimulation and verified through comparison to flat photovoltaic arrays. Models were applied to optimize the design of 3D electrode structures (pillars and honeycombs). Return electrodes on honeycomb walls vertically align the electric field with bipolar cells for optimal stimulation. Pillars elevate the active electrode, thus improving proximity to target neurons. The optimized 3D structures were electroplated onto existing flat subretinal prostheses.Main results.Simulations demonstrate that despite exposed conductive sidewalls, charge mostly flows via high-capacitance sputtered iridium oxide films topping the 3D structures. The 24µm height of honeycomb structures was optimized for integration with the inner nuclear layer cells in the rat retina, whilst 35µm tall pillars were optimized for penetrating the debris layer in human patients. Implantation of released 3D arrays demonstrates mechanical robustness, with histology demonstrating successful integration of 3D structures with the rat retinain-vivo.Significance. Electroplated 3D honeycomb structures produce vertically oriented electric fields, providing low stimulation thresholds, high spatial resolution, and high contrast for pixel sizes down to 20µm. Pillar electrodes offer an alternative for extending past the debris layer. Electroplating of 3D structures is compatible with the fabrication process of flat photovoltaic arrays, enabling much more efficient retinal stimulation.

Intranasal Immunization for Zika in a Pre-Clinical Model.

Humans continue to be at risk from the Zika virus. Although there have been significant research advancements regarding Zika, the absence of a vaccine or approved treatment poses further challenges for healthcare providers. In this study, we developed a microparticulate Zika vaccine using an inactivated whole Zika virus as the antigen that can be administered pain-free via intranasal (IN) immunization. These microparticles (MP) were formulated using a double emulsion method developed by our lab. We explored a prime dose and two-booster-dose vaccination strategy using MPL-A® and Alhydrogel® as adjuvants to further stimulate the immune response. MPL-A® induces a Th1-mediated immune response and Alhydrogel® (alum) induces a Th2-mediated immune response. There was a high recovery yield of MPs, less than 5 µm in size, and particle charge of -19.42 ± 0.66 mV. IN immunization of Zika MP vaccine and the adjuvanted Zika MP vaccine showed a robust humoral response as indicated by several antibodies (IgA, IgM, and IgG) and several IgG subtypes (IgG1, IgG2a, and IgG3). Vaccine MP elicited a balance Th1- and Th2-mediated immune response. Immune organs, such as the spleen and lymph nodes, exhibited a significant increase in CD4+ helper and CD8+ cytotoxic T-cell cellular response in both vaccine groups. Zika MP vaccine and adjuvanted Zika MP vaccine displayed a robust memory response (CD27 and CD45R) in the spleen and lymph nodes. Adjuvanted vaccine-induced higher Zika-specific intracellular cytokines than the unadjuvanted vaccine. Our results suggest that more than one dose or multiple doses may be necessary to achieve necessary immunological responses. Compared to unvaccinated mice, the Zika vaccine MP and adjuvanted MP vaccine when administered via intranasal route demonstrated robust humoral, cellular, and memory responses. In this pre-clinical study, we established a pain-free microparticulate Zika vaccine that produced a significant immune response when administered intranasally.

Buccal Administration of a Zika Virus Vaccine Utilizing 3D-Printed Oral Dissolving Films in a Mouse Model.

Over the years, research regarding the Zika virus has been steadily increasing. Early immunization for ZIKV is a priority for preventing complications such as microencephaly and Guillain-Barré syndrome (GBS). Unlike traditional vaccination approaches, oral dissolving films (ODFs) or mucoadhesive film technology is an emerging, exciting concept that can be used in the field of pharmaceuticals for vaccine design and formulation development. This attractive and novel method can help patients who suffer from dysphagia as a complication of a disease or syndrome. In this study, we investigated a microparticulate Zika vaccine administered via the buccal route with the help of thin films or oral dissolving films (ODFs) with a prime dose and two booster doses two weeks apart. In vitro, the ODFs displayed excellent physiochemical properties, indicating that the films were good carriers for vaccine microparticles and biocompatible with the buccal mucosa. In vivo results revealed robust humoral (IgG, subtypes IgG1 and IgG2a) and T-cell responses (CD4+/CD8+) for ZIKV-specific immunity. Both the Zika MP vaccine and the adjuvanted Zika MP vaccine affected memory (CD45R/CD27) and intracellular cytokine (TNF-α and IL-6) expression. In this study, ZIKV vaccination via the buccal route with the aid of ODFs demonstrated great promise for the development of pain-free vaccines for infectious diseases.

Impact of neoadjuvant relugolix on patient-reported sexual function and bother.

Introduction: Sexual function following local treatment for prostate cancer is an important quality of life concern. Relugolix is a novel oral GnRH receptor antagonist used in combination with radiation therapy in the treatment of unfavorable prostate cancer. It has been shown to achieve rapid and profound testosterone suppression. As a result, these very low testosterone levels may impact both sexual functioning and perceptions. This prospective study sought to assess neoadjuvant relugolix-induced sexual dysfunction prior to stereotactic body radiation therapy (SBRT). Methods: Between March 2021 and September 2023, 87 patients with localized prostate cancer were treated with neoadjuvant relugolix followed by SBRT per an institutional protocol. Sexual function and bother were assessed via the sexual domain of the validated Expanded Prostate Index Composite (EPIC-26) survey. Responses were collected for each patient at pre-treatment baseline and after several months of relugolix. A Utilization of Sexual Medications/Devices questionnaire was administered at the same time points to assess erectile aid usage. Results: The median age was 72 years and 43% of patients were non-white. The median baseline Sexual Health Inventory for Men (SHIM) score was 13 and 41.7% of patients utilized sexual aids prior to relugolix. Patients initiated relugolix at a median of 4.5 months (2-14 months) prior to SBRT. 95% and 87% of patients achieved effective castration (≤ 50 ng/dL) and profound castration (< 20 ng/dl) at SBRT initiation, respectively. Ability to have an erection, ability to reach orgasm, quality of erections, frequency of erections, and overall sexual function significantly declined following relugolix. There was a non- significant increase in sexual bother. Discussion: In concordance with known side effects of androgen deprivation therapy (ADT), neoadjuvant relugolix was associated with a significant decline in self-reported sexual function. However, patients indicated only a minimal and non-significant increase in bother. Future investigations should compare outcomes while on relugolix directly to GnRH agonist-induced sexual dysfunction.

Bothersome Hot Flashes Following Neoadjuvant Androgen Deprivation Therapy and Stereotactic Body Radiotherapy for Localized Prostate Cancer.

BACKGROUND: Androgen deprivation therapy (ADT) improves local cancer control in unfavorable localized prostate cancer treated with radiotherapy. ADT is known to cause hormonally related symptoms that resolve with testosterone recovery. Hot flashes are particularly burdensome. This study sought to evaluate the timeline of hot flashes following short-course ADT and stereotactic body radiotherapy (SBRT) as well as its relationship with testosterone recovery. METHODS: Institutional IRB approval was obtained for this retrospective review of prospectively collected data (IRB#: 2009-510). ADT was initiated three months prior to the start of SBRT. Hot flashes were self-reported via question 13a of the Expanded Prostate Index Composite (EPIC)-26 prior to ADT initiation, the first day of robotic SBRT, and at each follow-up (one, three, six, nine, 12, 18, 24, and 36 months). The responses were grouped into three relevant categories (no problem, very small-small problem, and moderate-big problem). Scores were transformed to a 0-100 scale with higher scores reflecting less bother. Testosterone levels were measured at each follow-up. RESULTS: From 2007 to 2010, 122 localized prostate cancer patients (nine low-, 64 intermediate-, and 49 high-risk according to the D'Amico classification) at a median age of 72 years (range 54.5-88.3) were treated with short course ADT (three to six months) and SBRT (35-36.25 Gy) at Georgetown University Hospital. Thirty-two percent were Black and 27% were obese. Seventy-seven percent of patients received three months of ADT. At baseline, 2% of men experienced hot flashes that were a "moderate to big problem" and that proportion peaked at the start of SBRT (45%) before returning to baseline (2%) nine months post-SBRT with a cumulative incidence of 52.4%. The median baseline EPIC-26 hot flash score of 94 declined to 50 at the start of SBRT but this returned to baseline (92) by six months post SBRT. These changes were both statistically and clinically significant (MID = 9.5083, p<0.01). Testosterone recovery (> 230 ng/dL) occurred in approximately 70% of patients by 12 months post SBRT. Resolution of hot flashes correlated with testosterone recovery. CONCLUSION: Bothersome hot flashes occur in greater than 50% of men treated with neoadjuvant ADT. Resolution of hot flashes occurs in the majority of patients within one year after treatment. Reassurance of the temporary nature of hot flashes may assist in reducing patient anxiety. Measuring testosterone levels at follow-up visits may allow for anticipatory counseling that may limit the associated bother.

Stereotactic Body Radiation Therapy for Clinically Localized Prostate Cancer in Men With Hip Prostheses: A Cautionary Note.

PURPOSE: Stereotactic body radiation therapy (SBRT) has been established as a safe and effective treatment for prostate cancer. SBRT requires high accuracy to reduce treatment margins. Metal hip prostheses create artifacts that distort pelvic imaging and potentially decrease the accuracy of target/organ at risk (OAR) identification and radiation dose calculations. Data on the safety and efficacy of SBRT after hip replacement is limited. This single-institution study sought to evaluate the safety and local control following SBRT for prostate cancer in men with hip replacements. METHODS: 23 patients treated with localized prostate cancer and a history of pre-treatment hip replacement, treated with SBRT from 2007 to 2017 at MedStar Georgetown University Hospital were included in this retrospective analysis. Treatment was administered with the CyberKnife® (Accuray Incorporated, Sunnyvale, CA) at doses of 35 Gy or 36.25 Gy in 5 fractions. The targets and OARs were identified and contoured by a single experienced Radiation Oncologist (SPC). The adequacy of the CT and T2W MRI images for treatment planning was assessed with a three-point scale (good, adequate, or suboptimal). During treatment planning, care was taken to avoid treatment beams that directly traversed the hip prosthesis. Toxicities were recorded and scored using the Common Terminology Criteria for Adverse Events version 4.0 (CTCAE v.4.0). Local recurrence was confirmed by magnetic resonance imaging and/or prostate biopsy. RESULTS: The median follow-up was seven years. The patients were elderly (median age = 71 years) with a high rate of comorbidities (Charlson Comorbidity Index > 2 in 25%). Four patients had bilateral hip replacements. The majority of patients were low to intermediate risk per the D'Amico classification. Around 13% received upfront ADT. In total, 13 patients were treated with 35 Gy, and 10 were treated with 36.25 Gy. The rates of late > Grade 3 GU toxicity and > Grade 2 GI toxicity were 8.6% and 4.3%, respectively. There were no Grade 4 or 5 toxicities. Six patients (26%) developed a local recurrence at a median time of 7.5 years. Of these six patients, four had unilateral hip replacements and two had bilateral. Three underwent salvage cryotherapy and three received salvage ADT. CONCLUSIONS:  In the general population, high-grade toxicities and local recurrences are uncommon following prostate SBRT. However, in this cohort of patients with prior hip replacements, prostate SBRT had higher than expected rates of late toxicity and local recurrence. In the opinion of the authors, such patients should be counseled regarding an elevated risk of late toxicity and local recurrence with prostate SBRT. With its ultrasound guidance, brachytherapy would have the advantage of circumventing the need for MRI/CT-based imaging and thus may represent a preferable radiation alternative in this patient population. If these patients are treated with SBRT, they should be monitored closely for local recurrence so early salvage can be performed. We hope that recent advances in metal artifact reduction techniques and dose-calculation algorithms will improve future outcomes.

3D electronic implants in subretinal space: Long-term follow-up in rodents.

Clinical results with photovoltaic subretinal prosthesis (PRIMA) demonstrated restoration of sight via electrical stimulation of the interneurons in degenerated retina, with resolution matching the 100 µm pixel size. Since scaling the pixels below 75 µm in the current bipolar planar geometry will significantly limit the penetration depth of the electric field and increase stimulation threshold, we explore the possibility of using smaller pixels based on a novel 3-dimensional honeycomb-shaped design. We assessed the long-term biocompatibility and stability of these arrays in rats by investigating the anatomical integration of the retina with flat and 3D implants and response to electrical stimulation over lifetime - up to 32-36 weeks post-implantation in aged rats. With both flat and 3D implants, signals elicited in the visual cortex decreased after the day of implantation by more than 3-fold, and gradually recovered over the next 12-16 weeks. With 25 µm high honeycomb walls, the majority of bipolar cells migrate into the wells, while amacrine and ganglion cells remain above the cavities, which is essential for selective network-mediated stimulation of the retina. Retinal thickness and full-field stimulation threshold with 40 µm-wide honeycomb pixels were comparable to those with planar devices - 0.05 mW/mm2 with 10 ms pulses. However, fewer cells from the inner nuclear layer migrated into the 20 µm-wide wells, and stimulation threshold increased over 12-16 weeks, before stabilizing at about 0.08 mW/mm2. Such threshold is still significantly lower than 1.8 mW/mm2 with a previous design of flat bipolar pixels, confirming the promise of the 3D honeycomb-based approach to high resolution subretinal prosthesis.

Enhancing Prosthetic Vision by Upgrade of a Subretinal Photovoltaic Implant in situ.

In patients with atrophic age-related macular degeneration, subretinal photovoltaic implant (PRIMA) provided visual acuity up to 20/440, matching its 100µm pixels size. Next-generation implants with smaller pixels should significantly improve the acuity. This study in rats evaluates removal of a subretinal implant, replacement with a newer device, and the resulting grating acuity in-vivo. Six weeks after the initial implantation with planar and 3-dimensional devices, the retina was re-detached, and the devices were successfully removed. Histology demonstrated a preserved inner nuclear layer. Re-implantation of new devices into the same location demonstrated retinal re-attachment to a new implant. New devices with 22µm pixels increased the grating acuity from the 100µm capability of PRIMA implants to 28µm, reaching the limit of natural resolution in rats. Reimplanted devices exhibited the same stimulation threshold as for the first implantation of the same implants in a control group. This study demonstrates the feasibility of safely upgrading the subretinal photovoltaic implants to improve prosthetic visual acuity.

The impact of neoadjuvant relugolix on multi-dimensional patient-reported fatigue.

Introduction: Androgen deprivation therapy has been shown to improve cancer control when combined with radiotherapy. Relugolix is an oral GnRH receptor antagonist that achieves rapid profound testosterone suppression, which may increase the perception and/or impact of fatigue. This study sought to evaluate neoadjuvant relugolix-induced fatigue in prostate cancer patients prior to the start of stereotactic body radiation therapy (SBRT). Methods: Relugolix was initiated at least two months before SBRT. The 13-item Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F) questionnaire was collected at baseline and one hour prior to SBRT initiation. A five-point scale was used to score individual items. Overall scores range from 0-52 and individual item scores were converted to 0-100, with higher scores reflecting less fatigue. Five "experience" items explored self-perceptions of fatigue, and eight "impact" items sought to evaluate the effect of fatigue on daily activities. Items were evaluated for statistical significance (paired t-test, p < 0.05) and clinical significance (minimally important difference (MID); 0.5 standard deviation from baseline). Results: Between March 2021 to December 2023, 89 men were treated at Georgetown with neoadjuvant relugolix and SBRT. Mean age was 71 years (range: 49-87). Median initiation of relugolix was 4.5 months prior to SBRT (range: 2-14.2 months). 93% patients achieved castration (testosterone levels ≤ 50 ng/dL) and 85% patients achieved profound castration (testosterone levels ≤ 20 ng/dL). 87 patients completed the FACIT-F questionnaire, with an average overall score of 45.6 at baseline and 41.0 at SBRT initiation. This difference was statistically and clinically significant (p < 0.01, MID = 3.55). Patients experienced an increase in fatigue for 12 of 13 items, with statistically significant changes for 11 items. Three of five experience items showed a clinically significant increase in fatigue. Only two of eight impact items were clinically significant. Discussion: Our study shows that relugolix significantly increases fatigue, affecting multiple areas of life. While the fatigue does not appear to generally impact a patient's ability to carry out normal activities, patients demonstrate frustration with being too tired for these activities. It is essential for clinicians to counsel prostate cancer patients on the impact of neoadjuvant relugolix on quality-of-life issues like fatigue.

Investigation of [11C]carfentanil for mu opioid receptor quantification in the rat brain.

[11C]Carfentanil ([11C]CFN) is the only selective carbon-11 labeled radiotracer currently available for positron emission tomography (PET) imaging of mu opioid receptors (MORs). Though used extensively in clinical research, [11C]CFN has not been thoroughly characterized as a tool for preclinical PET imaging. As we were occasionally observing severe vital sign instability in rat [11C]CFN studies, we set out to investigate physiological effects of CFN mass and to explore its influence on MOR quantification. In anesthetized rats (n = 15), significant dose-dependent PCO2 increases and heart rate decreases were observed at a conventional tracer dose range (IV, > 100 ng/kg). Next, we conducted baseline and retest [11C]CFN PET scans over a wide range of molar activities. Baseline [11C]CFN PET studies (n = 27) found that nondisplaceable binding potential (BPND) in the thalamus was positively correlated to CFN injected mass, demonstrating increase of MOR availability at higher injected CFN mass. Consistently, when CFN injected mass was constrained < 40 ng/kg (~ 10% MOR occupancy in rats), baseline MOR availability was significantly decreased. For test-retest variability (TRTV), better reproducibility was achieved by controlling CFN injected mass to limit the difference between scans. Taken together, we report significant cardiorespiratory depression and a paradoxical influence on baseline MOR availability at conventional tracer doses in rats. Our findings might reflect changes in cerebral blood flow, changes in receptor affinity, or receptor internalization, and merits further mechanistic investigation. In conclusion, rat [11C]CFN PET requires stringent quality assurance of radiotracer synthesis and mass injected to avoid pharmacological effects and limit potential influences on MOR quantification and reproducibility.

Evaluating the Release of Different Commercial Orally Modified Niacin Formulations In Vitro.

OBJECTIVES: To evaluate the release profile of different modified-release oral formulations of niacin, such as immediate-release (IR) powder and tablets, timed-release (TR) caplets, extended-release (ER) capsules, and controlled-release (CR) tablets, to assure their defined release pattern and correlate this release with their matrix polymers. SIGNIFICANCE: Niacin is used to manage hyperlipidemia by reducing cutaneous flushing and hepatotoxicity adverse events. The release profiles of different types of modified-release dosage forms depend on the types of coating materials (polymers) used in the matrix formation. Although different types of niacin formulations exist, none of the niacin dissolution profiles have been evaluated and compared in the literature. METHODS: Four commercial orally modified-release niacin brands were collected from a local CVS pharmacy retail store, in Miami, FL, USA. The in vitro release study was conducted in simulated gastric fluid (SGF) and simulated intestinal fluid (SIF) conditions. RESULTS: The results of the release patterns of four niacin-modified dosage forms (IR, ER, TR, and CR) were aligned with their release definitions. However, the CR dosage form did not follow an ideal release pattern. CONCLUSIONS: The release rate of niacin in vitro was pH dependent, which was confirmed by the similarity factor (f2) results. All the f2 comparison values were below 50 in both the SIF and SGF media, while all the comparisons were below the f2 values for all brands in the SIF media.

The Autoinducer N-Octanoyl-L-Homoserine Lactone (C8-HSL) as a Potential Adjuvant in Vaccine Formulations.

Autoinducers AI-1 and AI-2 play an important role in bacterial quorum sensing (QS), a form of chemical communication between bacteria. The autoinducer N-octanoyl-L-Homoserinehomoserine lactone (C8-HSL) serves as a major inter- and intraspecies communicator or 'signal', mainly for Gram-negative bacteria. C8-HSL is proposed to have immunogenic properties. The aim of this project is to evaluate C8-HSL as a potential vaccine adjuvant. For this purpose, a microparticulate formulation was developed. The C8-HSL microparticles (MPs) were formulated by a water/oil/water (W/O/W) double-emulsion solvent evaporation method using PLGA (poly (lactic-co-glycolic acid)) polymer. We tested C8-HSL MPs with two spray-dried bovine serum albumin (BSA)-encapsulated bacterial antigens: colonization factor antigen I (CFA/I) from Escherichia coli (E. coli.) and the inactive protective antigen (PA) from Bacillus anthracis (B. anthracis). We formulated and tested C8-HSL MP to determine its immunogenicity potential and its ability to serve as an adjuvant with particulate vaccine formulations. An in vitro immunogenicity assessment was performed using Griess's assay, which indirectly measures the nitric oxide radical (NOˑ) released by dendritic cells (DCs). The C8-HSL MP adjuvant was compared with FDA-approved adjuvants to determine its immunogenicity potential. C8-HSL MP was combined with particulate vaccines for measles, Zika and the marketed influenza vaccine. The cytotoxicity study showed that MPs were non-cytotoxic toward DCs. Griess's assay showed a comparable release of NOˑ from DCs when exposed to CFA and PA bacterial antigens. Nitric oxide radical (NOˑ) release was significantly higher when C8-HSL MPs were combined with particulate vaccines for measles and Zika. C8-HSL MPs showed immunostimulatory potential when combined with the influenza vaccine. The results showed that C8-HSL MPs were as immunogenic as FDA-approved adjuvants such as alum, MF59, and CpG. This proof-of-concept study showed that C8-HSL MP displayed adjuvant potential when combined with several particulate vaccines, indicating that C8-HSL MPs can increase the immunogenicity of both bacterial and viral vaccines.

Three-dimensional electro-neural interfaces electroplated on subretinal prostheses.

Objective: High-resolution retinal prosthetics offer partial restoration of sight to patients blinded by retinal degenerative diseases through electrical stimulation of the remaining neurons. Decreasing the pixel size enables an increase in prosthetic visual acuity, as demonstrated in animal models of retinal degeneration. However, scaling down the size of planar pixels is limited by the reduced penetration depth of the electric field in tissue. We investigate 3-dimensional structures on top of the photovoltaic arrays for enhanced penetration of electric field to permit higher-resolution implants. Approach: We developed 3D COMSOL models of subretinal photovoltaic arrays that accurately quantify the device electrodynamics during stimulation and verified it experimentally through comparison with the standard (flat) photovoltaic arrays. The models were then applied to optimise the design of 3D electrode structures (pillars and honeycombs) to efficiently stimulate the inner retinal neurons. The return electrodes elevated on top of the honeycomb walls surrounding each pixel orient the electric field inside the cavities vertically, aligning it with bipolar cells for optimal stimulation. Alternatively, pillars elevate the active electrode into the inner nuclear layer, improving proximity to the target neurons. Modelling results informed a microfabrication process of electroplating the 3D electrode structures on top of the existing flat subretinal prosthesis. Main results: Simulations demonstrate that despite the conductive sidewalls of the 3D electrodes being exposed to electrolyte, most of the charge flows via the high-capacitance sputtered Iridium Oxide film that caps the top of the 3D structures. The 24 µm height of the electroplated honeycomb structures was optimised for integration with the inner nuclear layer cells in rat retina, while 35 µm height of the pillars was optimized for penetrating the debris layer in human patients. Release from the wafer and implantation of the 3D arrays demonstrated that they are mechanically robust to withstand the associated forces. Histology demonstrated successful integration of the 3D structures with the rat retina in-vivo. Significance: Electroplated 3D honeycomb structures produce a vertically oriented electric field that offers low stimulation threshold, high spatial resolution and high contrast for the retinal implants with pixel sizes down to 20µm in width. Pillar electrodes offer an alternative configuration for extending the stimulation past the debris layers. Electroplating of the 3D structures is compatible with the fabrication process of the flat photovoltaic arrays, thereby enabling much more efficient stimulation than in their original flat configuration.

Testosterone as a Biomarker for Quality of Life (QOL) Following Androgen Deprivation Therapy (ADT) and Stereotactic Body Radiotherapy (SBRT).

BACKGROUND: Androgen deprivation therapy (ADT) causes fatigue and sexual dysfunction. The time to testosterone recovery depends on patient and treatment-specific characteristics. The kinetics of testosterone recovery in men treated with neoadjuvant ADT and stereotactic body radiotherapy (SBRT) is not well established. This study seeks to characterize testosterone recovery and evaluate its relationship with the improvement in patient-reported hormonal and sexual function. METHODS: Institutional review board (IRB) approval was obtained for retrospective review of prospectively collected data. All patients with localized prostate cancer treated with short-course ADT (3-6 months of Leuprolide) and robotic SBRT (35-36.25 Gy in five fractions) at a single institution were included in this analysis. Testosterone levels were measured at the start of radiation, every 3 months for the first year, and every 6 months thereafter. Total testosterone recovery was defined as a serum level of >230 ng/dL. Sexual and hormonal function was recorded using the Expanded Prostate Index Composite (EPIC)-26 prior to ADT initiation, the first day of SBRT, and at each follow-up. The EPIC-26 subdomain scores were transformed to a 0-100 scale with higher scores reflecting less bother. RESULTS: Between January 2009 and May 2018, 122 men with a median age of 72 years (range: 55-89 years) received ADT followed by SBRT. Thirty-two percent (N=39) were black and 27% [N=39 were obese (BMI > 30)]. The median pre-SBRT testosterone level was 15 ng/dL (range: 3-89 ng/dL). Around 77% (N=94) of patients received 3 months of ADT. The median pre-ADT EPIC-26 Hormone and Sexual Domain Scores were 94 and 41, respectively. At 12 months, 71% (N=87) of patients recovered to a eugonadal state with a mean recovery time of 4 months post-SBRT. Hormonal and sexual subdomain scores declined significantly following ADT but recovered to within the minimally important difference (MID) for sexual and hormonal domain scores by 12 months post-SBRT. CONCLUSIONS: Testosterone recovery following short-course ADT with leuprolide and SBRT occurs rapidly in the majority of patients within one year after treatment. Quality of life domain improvements followed the testosterone recovery trend closely. Testosterone testing at follow-up appointments would allow for anticipatory counseling that may limit the bother associated with temporary quality of life decrements.

3D electronic implants in subretinal space: long-term follow-up in rodents.

Photovoltaic subretinal prosthesis (PRIMA) enables restoration of sight via electrical stimulation of the interneurons in degenerated retina, with resolution limited by the 100 µm pixel size. Since decreasing the pixel size below 75 µm in the current bipolar geometry is impossible, we explore the possibility of using smaller pixels based on a novel 3-dimensional honeycomb-shaped design. We assessed the long-term biocompatibility and stability of these arrays in rats by investigating the anatomical integration of the retina with flat and 3D implants and response to electrical stimulation over lifetime - up to 9 months post-implantation in aged rats. With both flat and 3D implants, VEP amplitude decreased after the day of implantation by more than 3-fold, and gradually recovered over about 3 months. With 25 µm high honeycomb walls, the majority of bipolar cells migrate into the wells, while amacrine and ganglion cells remain above the cavities, which is essential for selective network-mediated stimulation of the second-order neurons. Retinal thickness and full-field stimulation threshold with 40 µm-wide honeycomb pixels were comparable to those with planar devices - 0.05 mW/mm2 with 10ms pulses. However, fewer cells from the inner nuclear layer migrated into the 20 µm-wide wells, and stimulation threshold increased over 5 months, before stabilizing at about 0.08 mW/mm2. Such threshold is significantly lower than 1.8 mW/mm2 with a previous design of flat bipolar pixels, confirming the promise of the 3D honeycomb-based approach to high resolution subretinal prosthesis.

Early biochemical outcomes following neoadjuvant/adjuvant relugolix with stereotactic body radiation therapy for intermediate to high risk prostate cancer.

Introduction: Injectable GnRH receptor agonists have been shown to improve cancer control when combined with radiotherapy. Prostate SBRT offers an abbreviated treatment course with comparable efficacy to conventionally fractionated radiotherapy. Relugolix is a new oral GnRH receptor antagonist which achieves rapid, sustained testosterone suppression. This prospective study sought to evaluate early testosterone suppression and PSA response following relugolix and SBRT for intermediate to high prostate cancer. Methods: Relugolix was initiated at least 2 months prior to SBRT. Interventions to improve adherence were not utilized. PSA and total testosterone levels were obtained prior to and 1-4 months post SBRT. Profound castration was defined as serum testosterone ≤ 20 ng/dL. Early PSA nadir was defined as the lowest PSA value within 4 months of completion of SBRT. Per prior trials, we examined the percentage of patients who achieved PSA level of ≤ 0.5 ng/mL and ≤ 0.2 ng/mL during the first 4 months post SBRT. Results: Between July 2021 and January 2023, 52 men were treated at Georgetown with relugolix (4-6 months) and SBRT (36.25-40 Gy in 5 fractions) per an institutional protocol (IRB 12-1775). Median age was 71 years. 26.9% of patients were African American and 28.8% were obese (BMI ≥30 kg/m2). The median pretreatment PSA was 9.1 ng/ml. 67% of patients were ≥ Grade Group 3. 44 patients were intermediate- and 8 were high-risk. Patients initiated relugolix at a median of 3.6 months prior to SBRT with a median duration of 6.2 total months. 92.3% of patients achieved profound castration during relugolix treatment. Poor drug adherence was observed in 2 patients. A third patient chose to discontinue relugolix due to side effects. By post-SBRT month 4, 87.2% and 74.4% of patients achieved PSA levels ≤ 0.5 ng/ml and ≤ 0.2 ng/ml, respectively. Discussion: Relugolix combined with SBRT allows for high rates of profound castration with low early PSA nadirs. We observed a 96% testosterone suppresion rate without the utilization of scheduled cues/reminders. This finding supports the notion that patients with localized prostate cancer can consistently and successfully follow an oral ADT protocol without daily reminders. Given relugolix's potential benefits over injectable GnRH receptor agonists, its usage may be preferred in specific patient populations (fear of needles, prior cardiovascular events). Future studies should focus on boundaries to adherence in specific underserved populations.

Potential Applications of Microparticulate-Based Bacterial Outer Membrane Vesicles (OMVs) Vaccine Platform for Sexually Transmitted Diseases (STDs): Gonorrhea, Chlamydia, and Syphilis.

Sexually transmitted diseases (STDs) are a major global health issue. Approximately 250 million new cases of STDs occur each year globally. Currently, only three STDs (human papillomavirus (HPV), hepatitis A, and hepatitis B) are preventable by vaccines. Vaccines for other STDs, including gonorrhea, chlamydia, and syphilis, await successful development. Currently, all of these STDs are treated with antibiotics. However, the efficacy of antibiotics is facing growing challenge due to the emergence of bacterial resistance. Therefore, alternative therapeutic approaches, including the development of vaccines against these STDs, should be explored to tackle this important global public health issue. Mass vaccination could be more efficient in reducing the spread of these highly contagious diseases. Bacterial outer membrane vesicle (OMV) is a potential antigen used to prevent STDs. OMVs are released spontaneously during growth by many Gram-negative bacteria. They present a wide range of surface antigens in native conformation that possess interesting properties such as immunogenicity, adjuvant potential, and the ability to be taken up by immune cells, all of which make them an attractive target for application as vaccines against pathogenic bacteria. The major challenge associated with the use of OMVs is its fragile structure and stability. However, a particulate form of the vaccine could be a suitable delivery system that can protect the antigen from degradation by a harsh acidic or enzymatic environment. The particulate form of the vaccine can also act as an adjuvant by itself. This review will highlight some practical methods for formulating microparticulate OMV-based vaccines for STDs.

A Review on Current COVID-19 Vaccines and Evaluation of Particulate Vaccine Delivery Systems.

First detected in Wuhan, China, a highly contagious coronavirus, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), also known as COVID-19, spread globally in December of 2019. As of 19 September 2021, approximately 4.5 million people have died globally, and 215 million active cases have been reported. To date, six vaccines have been developed and approved for human use. However, current production and supply capabilities are unable to meet global demands to immunize the entire world population. Only a few countries have been able to successfully vaccinate many of their residents. Therefore, an alternative vaccine that can be prepared in an easy and cost-effective manner is urgently needed. A vaccine that could be prepared in this manner, as well as can be preserved and transported at room temperature, would be of great benefit to public health. It is possible to develop such an alternative vaccine by using nano- or microparticle platforms. These platforms address most of the existing vaccine limitations as they are stable at room temperature, are inexpensive to produce and distribute, can be administered orally, and do not require cold chain storage for transportation or preservation. Particulate vaccines can be administered as either oral solutions or in sublingual or buccal film dosage forms. Besides improved patient compliance, the major advantage of oral, sublingual, and buccal routes of administration is that they can elicit mucosal immunity. Mucosal immunity, along with systemic immunity, can be a strong defense against SARS-CoV-2 as the virus enters the system through inhalation or saliva. This review discusses the possibility to produce a particulate COVID vaccine by using nano- or microparticles as platforms for oral administration or in sublingual or buccal film dosage forms in order to accelerate global vaccination.