Dynamic transcriptome profiles within spermatogonial and spermatocyte populations during postnatal testis maturation revealed by single-cell sequencing.

Spermatogenesis is the process by which male gametes are formed from a self-renewing population of spermatogonial stem cells (SSCs) residing in the testis. SSCs represent less than 1% of the total testicular cell population in adults, but must achieve a stable balance between self-renewal and differentiation. Once differentiation has occurred, the newly formed and highly proliferative spermatogonia must then enter the meiotic program in which DNA content is doubled, then halved twice to create haploid gametes. While much is known about the critical cellular processes that take place during the specialized cell division that is meiosis, much less is known about how the spermatocytes in the "first-wave" in juveniles compare to those that contribute to long-term, "steady-state" spermatogenesis in adults. Given the strictly-defined developmental process of spermatogenesis, this study explored the transcriptional profiles of developmental cell stages during testis maturation. Using a combination of comprehensive germ cell sampling with high-resolution, single-cell-mRNA-sequencing, we have generated a reference dataset of germ cell gene expression. We show that discrete developmental stages of spermatogenesis possess significant differences in the transcriptional profiles from neonates compared to juveniles and adults. Importantly, these gene expression dynamics are also reflected at the protein level in their respective cell types. We also show differential utilization of many biological pathways with age in both spermatogonia and spermatocytes, demonstrating significantly different underlying gene regulatory programs in these cell types over the course of testis development and spermatogenic waves. This dataset represents the first unbiased sampling of spermatogonia and spermatocytes during testis maturation, at high-resolution, single-cell depth. Not only does this analysis reveal previously unknown transcriptional dynamics of a highly transitional cell population, it has also begun to reveal critical differences in biological pathway utilization in developing spermatogonia and spermatocytes, including response to DNA damage and double-strand breaks.

Utility of point-of-care synovial lactate to identify septic arthritis in the emergency department.

BACKGROUND: Synovial lactate is a promising biomarker to distinguish septic from aseptic arthritis. If available as a point-of care test, synovial lactate would be rapidly available to aid the emergency provider in clinical decision making. This study assesses the test characteristics of synovial lactate obtained using an EPOC© point-of-care (POC) analyzer to rapidly distinguish septic from aseptic arthritis in the emergency department. METHODS: We enrolled a convenience sample of patients with possible septic arthritis presenting to the emergency department at a large urban academic center between October 2016 and April 2018. Enrolled patients underwent arthrocentesis based on the clinical judgment of the treating provider. We obtained synovial lactate levels (SLL) from the POC device. Standard laboratory analysis, synovial fluid culture, emergency and hospital course, operative procedures, antibiotics, and discharge diagnosis were abstracted from the electronic medical record. RESULTS: Thirty-nine patients undergoing forty separate arthrocentesis procedures were enrolled in this study over the two-year period. The sensitivity and specificity of SLL ≥ 5 mmol/L was 0.55 and 0.76 respectively, with +LR 2.3 and -LR 0.6. The sensitivity and specificity of SLL ≥ 10 mmol/L was 0.27 and 0.97 respectively, with +LR 7.9 and -LR 0.8; SLL ≥ 10 mmol/L performed similarly to overall synovial WBC ≥ 50,000/µL by conventional laboratory testing. CONCLUSION: It is feasible to obtain a synovial lactate level using the EPOC© POC device. In our study, POC SLL performs similarly to other markers used to diagnose septic arthritis. Further study with larger sample sizes is warranted.

Pre-hospital qSOFA as a predictor of sepsis and mortality.

BACKGROUND: The quick sequential organ failure assessment score (qSOFA) has been proposed as a simple tool to identify patients with sepsis who are at risk for poor outcomes. Its utility in the pre-hospital setting has not been fully elucidated. METHODS: This is a retrospective observational study of adult patients arriving by ambulance in September 2016 to an academic emergency department in Fresno, California. The qSOFA score was calculated from pre-hospital vital signs. We investigated its association with sepsis, ED diagnosis of infection, and mortality. RESULTS: Of 2292 adult medical patients transported by ambulance during the study period, the sensitivity of qSOFA for sepsis and in-hospital mortality were 42.9% and 40.6%, respectively. Specificity of qSOFA for sepsis and mortality were 93.8% and 91.9%, respectively. Of those with an ED diagnosis of infection compared to all patients, qSOFA was more specific but less sensitive for sepsis. Increasing qSOFA score was associated with a discharge diagnosis of sepsis (OR 4.21, 95% CI 3.41-5.21, p < 0.001), in-hospital mortality (OR 3.30, 95% CI 2.28-4.78, p < 0.001), and ED diagnosis of infection (OR 1.37, 95% CI 1.18-1.58, p < 0.001). Higher qSOFA score was associated with triage to a higher acuity zone and longer hospital and ICU length of stay, but not up-triage during ED stay. CONCLUSIONS: Pre-hospital qSOFA is specific, but poorly sensitive, for sepsis and sepsis outcomes, especially among patients with an ED diagnosis of infection. Higher qSOFA score was associated with worse outcomes.

Provider attitudes toward oral preexposure prophylaxis for HIV prevention among high-risk men who have sex with men in Lima, Peru.

Oral preexposure prophylaxis (PrEP) was the first biomedical intervention to demonstrate efficacy in preventing HIV infection among men who have sex with men (MSM). Healthcare providers' attitudes toward PrEP will be critical in translating this finding into effective public health rollout programs. In a convenience sample of 186 healthcare providers in Peru, we assessed knowledge, barriers, and attitudes to prescribe and monitor HIV PrEP for high-risk MSM and transgender women, the populations with the highest HIV incidence in this setting. A total of 57.5% reported awareness of PrEP, and awareness was independently associated with caring for more than 50 MSM (OR: 3.67, p<0.002). Lack of local guidelines, concern about increased high-risk behavior, antiretroviral drug resistance, and limited availability of antiretrovirals for HIV-infected individuals were the most common barriers to prescribing PrEP. Of all physicians 44.6% indicated that they would be likely to prescribe oral PrEP now; likelihood to prescribe was higher if PrEP were supported by local guidelines (70.3%, p<0.001), if more trials supported its effectiveness (68.5%, p<0.001), and if intermittent use were shown to be effective (62.2%, p=0.019). Physicians were more likely to prescribe PrEP now if they care for more than 50 MSM (OR: 6.62, p=0.010). Infectious disease specialists were less likely to prescribe PrEP (OR: 0.10, p=0.003) than nonspecialists. Successful large-scale implementation of PrEP in Peru will require focused educational campaigns to increase awareness and address concerns among healthcare providers.