Continuing Low Awareness and Use of Pre-exposure Prophylaxis (PrEP) for HIV among People Who Inject Drugs (PWID), San Francisco, 2022.

Clinical trials provide evidence that pre-exposure prophylaxis (PrEP) prevents HIV acquisition including through sharing of injection equipment among people who inject drugs (PWID). However, uptake among many populations at risk for HIV has been slow, particularly among PWID. We examined data from the National HIV Behavioral Surveillance (NHBS) from San Francisco in 2022 to measure PrEP uptake and identify factors associated with PrEP awareness among PWID. Of 479 PWID with HIV-negative or unknown HIV status, 54.9% were aware of PrEP, 5.9% had discussed PrEP with a healthcare provider, and 1.5% had used PrEP in the past year. Lack of PrEP awareness was associated with being age 50 years and older (adjusted odds ratio [aOR] 0.40, 95% CI 0.27-0.60), being men who have sex with women (vs. men who have sex with men, aOR 0.47, 95% CI 0.24-0.92), having a disability (aOR 0.58, 95% CI 0.35-0.95), using heroin as their most frequently injected drug (aOR 0.51, 95% CI, 0.34-0.78), not having tested for HIV, HCV, or an STD in the past year (aOR 0.43, 95% CI 0.28-0.64), and not having access to new sterile needles in the past year (aOR 0.28, 95%CI 0.08-1.00). We found negligible change in the awareness and uptake of PrEP among PWID since previously measured in NHBS in 2018. Low PrEP use among PWID may be addressed by increasing provider discussion of PrEP with their PWID patients and clients during routine care, expanding testing for injection-related infections among PWID, and integrating PrEP access into harm reduction programs.

Optimization of Neurite Tracing and Further Characterization of Human Monocyte-Derived-Neuronal-like Cells.

Deficits in neuronal structure are consistently associated with neurodevelopmental illnesses such as autism and schizophrenia. Nonetheless, the inability to access neurons from clinical patients has limited the study of early neurostructural changes directly in patients' cells. This obstacle has been circumvented by differentiating stem cells into neurons, although the most used methodologies are time consuming. Therefore, we recently developed a relatively rapid (~20 days) protocol for transdifferentiating human circulating monocytes into neuronal-like cells. These monocyte-derived-neuronal-like cells (MDNCs) express several genes and proteins considered neuronal markers, such as MAP-2 and PSD-95. In addition, these cells conduct electrical activity. We have also previously shown that the structure of MDNCs is comparable with that of human developing neurons (HDNs) after 5 days in culture. Moreover, the neurostructure of MDNCs responds similarly to that of HDNs when exposed to colchicine and dopamine. In this manuscript, we expanded our characterization of MDNCs to include the expression of 12 neuronal genes, including tau. Following, we compared three different tracing approaches (two semi-automated and one automated) that enable tracing using photographs of live cells. This comparison is imperative for determining which neurite tracing method is more efficient in extracting neurostructural data from MDNCs and thus allowing researchers to take advantage of the faster yield provided by these neuronal-like cells. Surprisingly, it was one of the semi-automated methods that was the fastest, consisting of tracing only the longest primary and the longest secondary neurite. This tracing technique also detected more structural deficits. The only automated method tested, Volocity, detected MDNCs but failed to trace the entire neuritic length. Other advantages and disadvantages of the three tracing approaches are also presented and discussed.

Sub-millimeter imaging of brain-free water for rapid volume assessment in atrophic brains.

INTRODUCTION: Cerebral atrophy occurs in healthy aging, and in disease processes such as multiple sclerosis (MS), it correlates with disability accumulation. Imaging measurements of brain atrophy are commonly based on tissue segmentation, which is susceptible to classification errors and inconsistencies. High-resolution imaging techniques with strong contrast between brain parenchyma and cerebrospinal fluid (CSF) might allow fully automated, rapid, threshold-based determination of the free water in the brain. We hypothesized that total brain-free-water (BFW) volume and BFW volume expressed as a normalized fraction of the intracranial volume ("BFW fraction"), determined from heavily T2-weighted images, would be useful surrogates for cerebral atrophy and therefore would correlate with clinical measures of disability in MS. METHODS: Whole brains of 83 MS cases and 7 healthy volunteers were imaged with a 4.7-min, heavily T2-weighted sequence on a 3T MRI scanner, acquiring 650-µm isotropic voxels. MS cases were clinically assessed on the Expanded Disability Status Scale (EDSS), Scripps Neurological Rating Scale (SNRS), Paced Auditory Serial Addition Test (PASAT), 9-Hole Peg Test (9HPT), Symbol Digit Modalities Test (SDMT), and 25-Foot Timed Walk. Twelve of the MS cases were rescanned within an average of 1.8 months to assess reproducibility. Automated calculations of BFW volume and BFW fraction were correlated with clinical measures of disability upon adjusting for age and sex. Results were compared to data from T1-based approaches (SIENAX and Lesion-TOADS). RESULTS AND DISCUSSION: BFW volume was automatically derived from heavily T2-weighted images with no need for separate skull stripping. BFW volume and fraction had mean scan-rescan coefficients of variation of 1.5% and 1.9%, respectively, similar to the T1-based approaches tested here. BFW fraction more strongly correlated with clinical measures than T1-derived results. Among those clinical measures, modality-specific disability scores, such as SDMT and 9HPT, were more strongly associated with BFW fraction than composite measures, such as EDSS and SNRS. CONCLUSION: The BFW method robustly estimates cerebral atrophy in an automated, fast, and reliable manner, and as such may prove a useful addition to imaging protocols for clinical practice and trials.