A Fc engineering approach to define functional humoral correlates of immunity against Ebola virus.

Protective Ebola virus (EBOV) antibodies have neutralizing activity and induction of antibody constant domain (Fc)-mediated innate immune effector functions. Efforts to enhance Fc effector functionality often focus on maximizing antibody-dependent cellular cytotoxicity, yet distinct combinations of functions could be critical for antibody-mediated protection. As neutralizing antibodies have been cloned from EBOV disease survivors, we sought to identify survivor Fc effector profiles to help guide Fc optimization strategies. Survivors developed a range of functional antibody responses, and we therefore applied a rapid, high-throughput Fc engineering platform to define the most protective profiles. We generated a library of Fc variants with identical antigen-binding fragments (Fabs) from an EBOV neutralizing antibody. Fc variants with antibody-mediated complement deposition and moderate natural killer (NK) cell activity demonstrated complete protective activity in a stringent in vivo mouse model. Our findings highlight the importance of specific effector functions in antibody-mediated protection, and the experimental platform presents a generalizable resource for identifying correlates of immunity to guide therapeutic antibody design.

PathDIP 5: improving coverage and making enrichment analysis more biologically meaningful.

Pathway Data Integration Portal (PathDIP) is an integrated pathway database that was developed to increase functional gene annotation coverage and reduce bias in pathway enrichment analysis. PathDIP 5 provides multiple improvements to enable more interpretable analysis: users can perform enrichment analysis using all sources, separate sources or by combining specific pathway subsets; they can select the types of sources to use or the types of pathways for the analysis, reducing the number of resulting generic pathways or pathways not related to users' research question; users can use API. All pathways have been mapped to seven representative types. The results of pathway enrichment can be summarized through knowledge-based pathway consolidation. All curated pathways were mapped to 53 pathway ontology-based categories. In addition to genes, pathDIP 5 now includes metabolites. We updated existing databases, included two new sources, PathBank and MetabolicAtlas, and removed outdated databases. We enable users to analyse their results using Drugst.One, where a drug-gene network is created using only the user's genes in a specific pathway. Interpreting the results of any analysis is now improved by multiple charts on all the results pages. PathDIP 5 is freely available at https://ophid.utoronto.ca/pathDIP.

MirDIP 5.2: tissue context annotation and novel microRNA curation.

MirDIP is a well-established database that aggregates microRNA-gene human interactions from multiple databases to increase coverage, reduce bias, and improve usability by providing an integrated score proportional to the probability of the interaction occurring. In version 5.2, we removed eight outdated resources, added a new resource (miRNATIP), and ran five prediction algorithms for miRBase and mirGeneDB. In total, mirDIP 5.2 includes 46 364 047 predictions for 27 936 genes and 2734 microRNAs, making it the first database to provide interactions using data from mirGeneDB. Moreover, we curated and integrated 32 497 novel microRNAs from 14 publications to accelerate the use of these novel data. In this release, we also extend the content and functionality of mirDIP by associating contexts with microRNAs, genes, and microRNA-gene interactions. We collected and processed microRNA and gene expression data from 20 resources and acquired information on 330 tissue and disease contexts for 2657 microRNAs, 27 576 genes and 123 651 910 gene-microRNA-tissue interactions. Finally, we improved the usability of mirDIP by enabling the user to search the database using precursor IDs, and we integrated miRAnno, a network-based tool for identifying pathways linked to specific microRNAs. We also provide a mirDIP API to facilitate access to its integrated predictions. Updated mirDIP is available at https://ophid.utoronto.ca/mirDIP.

Small bites versus large bites during fascial closure of midline laparotomies: a systematic review and meta-analysis.

PURPOSE: Incisional ventral hernias (IVH) are common after laparotomies, with up to 20% incidence in 12 months, increasing up to 60% at 3-5 years. Although Small Bites (SB) is the standard technique for fascial closure in laparotomies, its adoption in the United States is limited, and Large Bites (LB) is still commonly performed. We aim to assess the effectiveness of SB regarding IVH. METHODS: We searched for RCTs and observational studies on Cochrane, EMBASE, and PubMed from inception to May 2023. We selected patients ≥ 18 years old, undergoing midline laparotomies, comparing SB and LB for IVH, surgical site infections (SSI), fascial dehiscence, hospital stay, and closure duration. We used RevMan 5.4. and RStudio for statistics. Heterogeneity was assessed with I2 statistics, and random effect was used if I2 > 25%. RESULTS: 1687 studies were screened, 45 reviewed, and 6 studies selected, including 3 RCTs and 3351 patients (49% received SB and 51% LB). SB showed fewer IVH (RR 0.54; 95% CI 0.39-0.74; P < 0.001) and SSI (RR 0.68; 95% CI 0.53-0.86; P = 0.002), shorter hospital stay (MD -1.36 days; 95% CI -2.35, -0.38; P = 0.007), and longer closure duration (MD 4.78 min; 95% CI 3.21-6.35; P < 0.001). No differences were seen regarding fascial dehiscence. CONCLUSION: SB technique has lower incidence of IVH at 1-year follow-up, less SSI, shorter hospital stay, and longer fascial closure duration when compared to the LB. SB should be the technique of choice during midline laparotomies.

Facial Nerve Considerations for the Deep Plane Facelift and Neck Lift.

The surgical approach to facial rejuvenation has evolved significantly over the last century. As surgeons have deepened their understanding of facial anatomy over the last half century, so have their surgical approaches to the rhytidectomy, with increasingly extensive manipulation of the underlying soft tissue in the face. While these procedures have become more comprehensive and natural in their approach, the risk of temporary facial palsy also appears to be on the rise. In this text, we review the technique for deep plane facelifts and neck contouring with an emphasis on the facial nerve anatomy and methods to preserve the intricate facial nerve network during tissue dissection and modification. Careful execution of the surgical steps involved, including deep neck contouring, SMAS (superficial musculoaponeurotic system) suspension, and skin management, is essential to achieve the authentic aesthetic outcomes that patients desire while ensuring patient safety.

Pitfalls and complications of enhanced-view totally extraperitoneal approach to abdominal wall reconstruction.

BACKGROUND: The enhanced-view totally extraperitoneal access technique (eTEP) to minimally invasive retromuscular abdominal wall reconstruction is a relatively novel technique that has continued to gain popularity. There is a paucity of information regarding the prevention and management of eTEP complications. We reviewed the literature to evaluate the complications reported with eTEP ventral hernia repair and discuss the main complications associated with this technique. METHODS: A literature search via PubMed was performed focusing on eTEP ventral hernia repair. Based on the available literature and own practice experience, the authors discuss key strategies for preventing and managing complications associated with the eTEP approach. RESULTS: One hundred fifty studies were identified. Forty-seven studies were fully reviewed and twenty-four were included in this review. The technical details of the technique were described as performed by the authors. Postoperative complications were classified into different categories and discussed separately. CONCLUSION: As the eTEP approach continues to gain popularity, it is essential to consider its unique complications. A focus on prevention with anatomical bearings and sound surgical technique is paramount.

pathDIP 4: an extended pathway annotations and enrichment analysis resource for human, model organisms and domesticated species.

PathDIP was introduced to increase proteome coverage of literature-curated human pathway databases. PathDIP 4 now integrates 24 major databases. To further reduce the number of proteins with no curated pathway annotation, pathDIP integrates pathways with physical protein-protein interactions (PPIs) to predict significant physical associations between proteins and curated pathways. For human, it provides pathway annotations for 5366 pathway orphans. Integrated pathway annotation now includes six model organisms and ten domesticated animals. A total of 6401 core and ortholog pathways have been curated from the literature or by annotating orthologs of human proteins in the literature-curated pathways. Extended pathways are the result of combining these pathways with protein-pathway associations that are predicted using organism-specific PPIs. Extended pathways expand proteome coverage from 81 088 to 120 621 proteins, making pathDIP 4 the largest publicly available pathway database for these organisms and providing a necessary platform for comprehensive pathway-enrichment analysis. PathDIP 4 users can customize their search and analysis by selecting organism, identifier and subset of pathways. Enrichment results and detailed annotations for input list can be obtained in different formats and views. To support automated bioinformatics workflows, Java, R and Python APIs are available for batch pathway annotation and enrichment analysis. PathDIP 4 is publicly available at http://ophid.utoronto.ca/pathDIP.

Hybrid versus open retromuscular abdominal wall repair: early outcomes.

BACKGROUND: The hybrid approach to abdominal wall reconstruction (AWR) for abdominal wall hernias combines minimally invasive posterior component separation and retromuscular dissection with open fascial closure and mesh implantation. This combination may enhance patient outcomes and recovery compared to the open approach alone. The purpose of this study is to evaluate the operative outcomes of hybrid vs. open abdominal wall reconstruction. METHODS: A retrospective review was conducted to compare patients who underwent open versus hybrid AWR between September 2015 and August of 2018 at Anne Arundel Medical Center. Patient demographics and perioperative data were collected and analyzed using univariate analysis. RESULTS: Sixty-five patients were included in the final analysis: 10 in the hybrid and 55 in the open groups. Mean age was higher in the hybrid vs. open group (65.1 vs. 56.2 years, p < 0.05). The hybrid and open groups were statistically similar (p > 0.05) in gender distribution, mean BMI, and ASA score. Intraoperative comparison found hybrid patients parallel to open patients (p > 0.05) in mean operative time (294.5 vs. 267.5 min), defect size (14.4 vs. 13.6 cm), mesh area, and drain placement. The mean total hospital cost was lower in the hybrid group compared to the open group ($16,426 vs. $19,054, p = 0.43). The hybrid group had a shorter length of stay (5.3 vs. 3.6 days, p = 0.03) after surgery and was followed for a similar length of time (12.3 vs. 12.6 months, p = 0.91). The hybrid group showed a lower trend of seroma, hematoma, wound infection, ileus, and readmission rates after surgery. CONCLUSION: A review of patient outcomes after hybrid AWR highlights a trend towards shorter length of stay, lower hospital cost, and fewer complications without significant addition to operative time. Long-term studies on a larger number of patients are definitively needed to characterize the comprehensive benefits of this approach.

Impact of Body Mass Index (BMI) on perioperative outcomes following minimally invasive retromuscular abdominal wall reconstruction: a comparative analysis.

BACKGROUND: Morbidity and recurrence rates are higher in obese patients undergoing open abdominal wall reconstruction (AWR). Historically, body mass index (BMI) ≥ 40 has served as a relative contraindication to open AWR. The purpose of this study is to evaluate the impact of minimally invasive surgery (MIS) on outcomes after AWR for higher versus lower BMI patients. METHODS: A retrospective review of a prospectively maintained database was conducted of all patients who underwent MIS AWR between September 2015 and April 2019 at our institution. Patients were subdivided into two groups based on their BMI: BMI ≤ 35 kg/m2 and BMI > 35 kg/m2. Patient demographics and perioperative data were evaluated using univariate and multivariate analysis. RESULTS: 461 patients were identified and divided into two groups: BMI ≤ 35 (n = 310) and BMI > 35 (n = 151). The two groups were similar in age (BMI ≤ 35: 56.3 ± 14.1 years vs. BMI > 35: 54.4 ± 11.9, p = .154). BMI > 35 group had more patients with ASA score of 3 (81% vs. 32%, p < .001) and comorbid conditions such as hypertension (70% vs. 45%, p < .001), diabetes mellitus (32% vs. 15%, p < .001), and history of recurrent abdominal wall hernia (34% vs. 23%, p = .008). BMI > 35 group underwent a robotic approach at higher rates (74% vs. 45%, p < .001). Patients who underwent a Rives-Stoppa repair from the higher BMI cohort also had a larger defect size (5.6 ± 2.4 cm vs. 6.7 ± 2.4 cm, p = .004). However, there were no differences in defect size in patients who underwent a transversus abdominus release (BMI ≤ 35: 9.7 ± 4.9 cm vs. BMI > 35: 11.1 ± 4.6 cm, p = .069). Both groups benefited similarly from a short length of stay, similar hospital charges, and lower postoperative complications. CONCLUSION: Initial findings of our data support the benefits of elective MIS approach to AWR for patients with higher BMI. These patients derive similar benefits, such as faster recovery with low recurrence rates, when compared to lower BMI patients, while avoiding preoperative hernia incarceration, postoperative wound complications, and hernia recurrences. Future follow-up is required to establish long-term perioperative and quality of life outcomes in this patient cohort.

Comparative review of outcomes: laparoscopic and robotic enhanced-view totally extraperitoneal (eTEP) access retrorectus repairs.

BACKGROUND: Building on the principles of eTEP access, described by Dr. Jorge Daes, our group has previously described and standardized a novel minimally invasive approach to restoration of the linea alba and repair of lateral atypical defects of the abdominal wall. The purpose of this report is to present comparative analysis of laparoscopic and robotic eTEP access retrorectus repairs. METHODS: A retrospective review was conducted in patients who underwent laparoscopic eTEP (lap-eRS) and robotic-assisted eTEP (robo-eRS) Rives-Stoppa repairs between September 2015 and May 2018 at our institution. We analyzed the preoperative demographics and the perioperative outcomes. RESULTS: Our review identified 206 patients (Lap-eRS 120 vs. robo-eRS 86). The groups were comparable (p > 0.05) in gender distribution (47.6% vs. 53% male) and mean age (53.2 vs. 50.8 years), but different (p < 0.05) in mean BMI (31.3 vs. 34.4 kg/m2) and ASA score (2.1 vs. 2.4). The robo-eRS group had a larger defect size (5.5 vs. 7.1 cm, p < 0.05), a longer mean operative time (120.4 vs. 174.7 min, p < 0.05), and a higher hospitalization cost ($5,091 vs. $6,751, p = 0.005) compared to the lap-eRS group. Average length of stay (0.2 vs. 0.1 days), length of drain placement (5.3 vs. 5.7 days), and reoperations (2.5% vs. 2.3%) were similar between lap-eRS and robo-eRS (p > 0.05). Patients in both groups (lap-eRS vs. robo-eRS) were followed for an average of 5.7 months vs. 5.5 months (p = .735) and showed similar recurrence rates (1.7% vs. 1.2%, p > 0.05). CONCLUSION: We present the largest series to-date of eTEP access laparoscopic and robotic ventral hernia retrorectus repairs. Morbidly obese patients and those with more complex abdominal wall defects were more likely to undergo a robo-eRS. The significantly longer operative time and higher hospital cost associated with the robo-eRS group may be in part due to these factors. Both robotic and laparoscopic eTEP Rives-Stoppa repairs are associated with favorable perioperative outcomes and low recurrence rates.

mirDIP 4.1-integrative database of human microRNA target predictions.

MicroRNAs are important regulators of gene expression, achieved by binding to the gene to be regulated. Even with modern high-throughput technologies, it is laborious and expensive to detect all possible microRNA targets. For this reason, several computational microRNA-target prediction tools have been developed, each with its own strengths and limitations. Integration of different tools has been a successful approach to minimize the shortcomings of individual databases. Here, we present mirDIP v4.1, providing nearly 152 million human microRNA-target predictions, which were collected across 30 different resources. We also introduce an integrative score, which was statistically inferred from the obtained predictions, and was assigned to each unique microRNA-target interaction to provide a unified measure of confidence. We demonstrate that integrating predictions across multiple resources does not cumulate prediction bias toward biological processes or pathways. mirDIP v4.1 is freely available at http://ophid.utoronto.ca/mirDIP/.

Shigella Effector OspB Activates mTORC1 in a Manner That Depends on IQGAP1 and Promotes Cell Proliferation.

The intracellular bacterial pathogen Shigella infects and spreads through the human intestinal epithelium. Effector proteins delivered by Shigella into cells promote infection by modulating diverse host functions. We demonstrate that the effector protein OspB interacts directly with the scaffolding protein IQGAP1, and that the absence of either OspB or IQGAP1 during infection leads to larger areas of S. flexneri spread through cell monolayers. We show that the effect on the area of bacterial spread is due to OspB triggering increased cell proliferation at the periphery of infected foci, thereby replacing some of the cells that die within infected foci and restricting the area of bacterial spread. We demonstrate that OspB enhancement of cell proliferation results from activation of mTORC1, a master regulator of cell growth, and is blocked by the mTORC1-specific inhibitor rapamycin. OspB activation of mTORC1, and its effects on cell proliferation and bacterial spread, depends on IQGAP1. Our results identify OspB as a regulator of mTORC1 and mTORC1-dependent cell proliferation early during S. flexneri infection and establish a role for IQGAP1 in mTORC1 signaling. They also raise the possibility that IQGAP1 serves as a scaffold for the assembly of an OspB-mTORC1 signaling complex.

Cooperativity of HIV-Specific Cytolytic CD4 T Cells and CD8 T Cells in Control of HIV Viremia.

UNLABELLED: CD4+ T cells play a pivotal role in the control of chronic viral infections. Recently, nontraditional CD4+ T cell functions beyond helper effects have been described, and a role for cytolytic CD4+ T cells in the control of HIV infection has been suggested. We define here the transcriptional, phenotypic, and functional profiles of HIV-specific cytolytic CD4+ T cells. Fluidigm BioMark and multiparameter flow cytometric analysis of HIV-specific cytolytic CD4+ T cells revealed a distinct transcriptional signature compared to Th1 CD4+ cells but shared similar features with HIV-specific cytolytic CD8+ T cells. Furthermore, HIV-specific cytolytic CD4+ T cells showed comparable killing activity relative to HIV-specific CD8+ T cells and worked cooperatively in the elimination of virally infected cells. Interestingly, we found that cytolytic CD4+ T cells emerge early during acute HIV infection and tightly follow acute viral load trajectory. This emergence was associated to the early viral set point, suggesting an involvement in early control, in spite of CD4 T cell susceptibility to HIV infection. Our data suggest cytolytic CD4+ T cells as an independent subset distinct from Th1 cells that show combined activity with CD8+ T cells in the long-term control of HIV infection. IMPORTANCE: The ability of the immune system to control chronic HIV infection is of critical interest to both vaccine design and therapeutic approaches. Much research has focused on the effect of the ability of CD8+ T cells to control the virus, while CD4+ T cells have been overlooked as effectors in HIV control due to the fact that they are preferentially infected. We show here that a subset of HIV-specific CD4+ T cells cooperate in the cytolytic control of HIV replication. Moreover, these cells represent a distinct subset of CD4+ T cells showing significant transcriptional and phenotypic differences compared to HIV-specific Th1 cells but with similarities to CD8+ T cells. These findings are important for our understanding of HIV immunopathology.

Emergence of individual HIV-specific CD8 T cell responses during primary HIV-1 infection can determine long-term disease outcome.

UNLABELLED: Events during primary HIV-1 infection have been shown to be critical for the subsequent rate of disease progression. Early control of viral replication, resolution of clinical symptoms and development of a viral set point have been associated with the emergence of HIV-specific CD8 T cell responses. Here we assessed which particular HIV-specific CD8 T cell responses contribute to long-term control of HIV-1. A total of 620 individuals with primary HIV-1 infection were screened by gamma interferon (IFN-γ) enzyme-linked immunospot (ELISPOT) assay for HLA class I-restricted, epitope-specific CD8 T cell responses using optimally defined epitopes approximately 2 months after initial presentation. The cohort was predominantly male (97%) and Caucasian (83%) (Fiebig stages II/III [n = 157], IV [n = 64], V [n = 286], and VI [n = 88] and Fiebig stage not determined [n = 25]). Longitudinal viral loads, CD4 count, and time to ART were collected for all patients. We observed strong associations between viral load at baseline (initial viremia) and the established early viral set points (P < 0.0001). Both were significantly associated with HLA class I genotypes (P = 0.0009). While neither the breadth nor the magnitude of HIV-specific CD8 T cell responses showed an influence on the early viral set point, a broader HIV-specific CD8 T cell response targeting epitopes within HIV-1 Gag during primary HIV-1 infection was associated with slower disease progression. Moreover, the induction of certain HIV-specific CD8 T cell responses--but not others--significantly influenced the time to ART initiation. Individual epitope-specific CD8 T cell responses contribute significantly to HIV-1 disease control, demonstrating that the specificity of the initial HIV-specific CD8 T cell response rather than the restricting HLA class I molecule alone is a critical determinant of antiviral function. IMPORTANCE: Understanding which factors are involved in the control of HIV-1 infection is critical for the design of therapeutic strategies for patients living with HIV/AIDS. Here, using a cohort of over 600 individuals with acute and early HIV-1 infection, we assessed in unprecedented detail the individual contribution of epitope-specific CD8 T cell responses directed against HIV-1 to control of viremia and their impact on the overall course of disease progression.

Induction of Gag-specific CD4 T cell responses during acute HIV infection is associated with improved viral control.

UNLABELLED: Effector CD4 T cell responses have been shown to be critically involved in the containment and clearance of viral pathogens. However, their involvement in the pathogenesis of HIV infection is less clear, given their additional role as preferred viral targets. We previously demonstrated that the presence of HIV-specific CD4 T cell responses is somewhat associated with HIV control and that specific CD4 T cell functions, such as direct cytolytic activity, can contribute to control of HIV viremia. However, little is known about how the induction of HIV-specific CD4 T cell responses during acute HIV infection influences disease progression and whether responses induced during the early phase of infection are preferentially depleted. We therefore longitudinally assessed, in a cohort of 55 acutely HIV-infected individuals, HIV-specific CD4 T cell responses from acute to chronic infection. Interestingly, we found that the breadth, magnitude, and protein dominance of HIV-specific CD4 T cell responses remained remarkably stable over time. Moreover, we found that the epitopes targeted at a high frequency in acute HIV infection were recognized at the same frequency by HIV-specific CD4 T cells in chronic HIV infection. Interestingly the induction of Gag-specific CD4 T cell responses in acute HIV infection was significantly inversely correlated with viral set point in chronic HIV infection (R = -0.5; P = 0.03), while the cumulative contribution of Env-specific CD4 T cell responses showed the reverse effect. Moreover, individuals with HIV-specific CD4 T cell responses dominantly targeting Gag over Env in acute HIV infection remained off antiretroviral therapy significantly longer (P = 0.03; log rank). Thus, our data suggest that the induction of HIV-specific CD4 T cell responses during acute HIV infection is beneficial overall and does not fuel disease progression. IMPORTANCE: CD4 T cells are critical for the clearance and control of viral infections. However, HIV preferentially infects HIV-specific CD4 T cells. Thus, their contribution to the control of HIV viremia is uncertain. Here, we study HIV-specific CD4 T cell responses from acute to chronic HIV infection and show that the generation of certain CD4 responses is associated with control rather than disease progression.

A richly interactive exploratory data analysis and visualization tool using electronic medical records.

BACKGROUND: Electronic medical records (EMRs) contain vast amounts of data that is of great interest to physicians, clinical researchers, and medial policy makers. As the size, complexity, and accessibility of EMRs grow, the ability to extract meaningful information from them has become an increasingly important problem to solve. METHODS: We develop a standardized data analysis process to support cohort study with a focus on a particular disease. We use an interactive divide-and-conquer approach to classify patients into relatively uniform within each group. It is a repetitive process enabling the user to divide the data into homogeneous subsets that can be visually examined, compared, and refined. The final visualization was driven by the transformed data, and user feedback direct to the corresponding operators which completed the repetitive process. The output results are shown in a Sankey diagram-style timeline, which is a particular kind of flow diagram for showing factors' states and transitions over time. RESULTS: This paper presented a visually rich, interactive web-based application, which could enable researchers to study any cohorts over time by using EMR data. The resulting visualizations help uncover hidden information in the data, compare differences between patient groups, determine critical factors that influence a particular disease, and help direct further analyses. We introduced and demonstrated this tool by using EMRs of 14,567 Chronic Kidney Disease (CKD) patients. CONCLUSIONS: We developed a visual mining system to support exploratory data analysis of multi-dimensional categorical EMR data. By using CKD as a model of disease, it was assembled by automated correlational analysis and human-curated visual evaluation. The visualization methods such as Sankey diagram can reveal useful knowledge about the particular disease cohort and the trajectories of the disease over time.

Cyclin dependent kinase 5 is required for the normal development of oligodendrocytes and myelin formation.

The development of oligodendrocytes, the myelinating cells of the vertebrate CNS, is regulated by a cohort of growth factors and transcription factors. Less is known about the signaling pathways that integrate extracellular signals with intracellular transcriptional regulators to control oligodendrocyte development. Cyclin dependent kinase 5 (Cdk5) and its co-activators play critical roles in the regulation of neuronal differentiation, cortical lamination, neuronal cell migration and axon outgrowth. Here we demonstrate a previously unrecognized function of Cdk5 in regulating oligodendrocyte maturation and myelination. During late embryonic development Cdk5 null animals displayed a reduction in the number of MBP+ cells in the spinal cord, but no difference in the number of OPCs. To determine whether the reduction of oligodendrocytes reflected a cell-intrinsic loss of Cdk5, it was selectively deleted from Olig1+ oligodendrocyte lineage cells. In Olig1(Cre/+); Cdk5(fl/fl) conditional mutants, reduced levels of expression of MBP and PLP mRNA were observed throughout the CNS and ultrastructural analyses demonstrated a significant reduction in the proportion of myelinated axons in the optic nerve and spinal cord. Pharmacological inhibition or RNAi knockdown of Cdk5 in vitro resulted in the reduction in oligodendrocyte maturation, but had no effect on OPC cell proliferation. Conversely, over-expression of Cdk5 promoted oligodendrocyte maturation and enhanced process outgrowth. Consistent with this data, Cdk5(-/-) oligodendrocytes developed significantly fewer primary processes and branches than control cells. Together, these findings suggest that Cdk5 function as a signaling integrator to regulate oligodendrocyte maturation and myelination.

Beyond-66: A pilot evaluation of a novel, peer-led harm reduction intervention for chemsex dependant men who have sex with men in Kuala Lumpur, Malaysia.

BACKGROUND: There is little research exploring harm reduction interventions for men who have sex with men (MSM) who engage in chemsex. Beyond-66 is a novel, 132-day, peer-led intervention programme for MSM who are chemsex dependent in Kuala Lumpur, Malaysia. We aimed to evaluate the feasibility, retention and effect of Beyond-66 on: abstinence from chemsex, motivation for abstinence, and mental wellbeing. METHOD: We collected data on demographics, retention and completion and abstinence between January 2021-August 2023 in MSM using Beyond-66. Using 10-point Likert scales, we compared motivation to remain abstinent and mental wellbeing at the beginning and end of Beyond-66. RESULTS: 25 MSM have either completed or dropped out/referred out of Beyond-66, 12/25(48%) were living with HIV and the median duration of chemsex use was 5 years (IQR = 4-6). 19 (76%) completed programme; 3 were referred out for a psychiatry assessment and 3 dropped out of the programme. 14 (74%) remain abstinent and 5 relapsed. The median motivation for abstinence scores for the 19 completers increased significantly between the pre-programme and post-programme period (7/10 (IQR = 4-8) to 9/10 (IQR = 5-10), p = .04) and the median mental health score (Likert score out of 10 where 10 is poor mental health) reduced significantly (5/10 (IQR = 4-7) to 2/10 (IQR 1-6), p = .008). CONCLUSION: This pilot evaluation suggests that MSM using Beyond-66 experience high completion (76%) and abstinence (74%) rates and increased motivation for abstinence and mental wellbeing scores. Further research is needed to design, develop, and deliver peer led interventions for MSM who are chemsex dependant.