UC San Diego

BACKGROUND AND AIMS: Elevated lipoprotein(a) [Lp(a)], high-sensitivity C-Reactive Protein (hs-CRP), and total homocysteine (tHcy) are associated with atherosclerotic cardiovascular disease (ASCVD) risk. This study investigated the individual and joint associations of Lp(a), hs-CRP and tHcy with coronary heart disease (CHD) and stroke. METHODS: This study was conducted in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort (2000-2017) (CHD analytic N = 6,676; stroke analytic N = 6,674 men and women). Associations between Lp(a) (<50 vs. ≥50 mg/dL), hs-CRP (<2 vs. ≥2 mg/L) and tHcy (<12 vs. ≥12 µmol/L) and CHD and stroke incidence were evaluated individually and jointly using Cox proportional hazards regression. RESULTS: Individually, elevated tHcy was associated with CHD and stroke incidence, Lp(a) with CHD only and hs-CRP with stroke only. In combined analyses, CHD risk was higher when multiple biomarkers were elevated [hs-CRP+Lp(a), hazard ratio (HR)=1.39, 95 % confidence interval (CI): 1.06, 1.82; hs-CRP+ tHcy, HR = 1.34, 95 % CI: 1.02, 1.75; Lp(a)+ tHcy HR = 1.58, 95 % CI: 1.08, 2.30; hs-CRP+Lp(a)+ tHcy HR = 2.02, 95 % CI: 1.26, 3.24]. Stroke risk was elevated when hs-CRP and either Lp(a) (HR = 1.51, 95 % CI: 1.02, 2.23) or tHcy (HR = 2.10, 95 % CI: 1.44, 3.06) was also high, when all three biomarkers were elevated (HR = 2.99, 95 % CI: 1.61, 5.58), or when hs-CRP and tHcy (HR = 1.79, 95 % CI: 1.16, 2.76) were both high. CONCLUSIONS: Risk of ASCVD was highest with concomitant elevation of tHcy, hs-CRP and Lp(a). Inclusion of tHcy and consideration of biomarker combination rather than individual biomarker levels may help better identify individuals at greatest risk for ASCVD events.

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BACKGROUND: For extended-release drug formulations, effective half-life (t 1/2eff ) is a relevant pharmacokinetic parameter to inform dosing strategies and time to reach steady state. Tacrolimus, an immunosuppressant commonly used for the prophylaxis of organ rejection in transplant patients, is available as both immediate- and extended-release formulations. To the best of our knowledge, the t 1/2eff of tacrolimus from these different formulations has not yet been assessed. The objective of this study was to characterize the t 1/2eff and terminal half-life (t 1/2z ) of an extended-release once-daily tacrolimus formulation (LCPT) and twice-daily immediate-release tacrolimus (IR-Tac). METHODS: A noncompartmental analysis of pharmacokinetic data obtained from a phase 2 study in de novo kidney transplant recipients receiving either LCPT or IR-Tac was conducted. Intensive blood sampling was performed on days 1, 7, and 14, and tacrolimus whole blood concentrations were measured using a validated liquid chromatography with tandem mass spectrometry method. T 1/2eff was estimated using within-participant accumulation ratios. T 1/2z was estimated by linear regression of the terminal phase of the concentration versus time profile. RESULTS: The median accumulation ratios of LCPT and IR-Tac on day 14 were 3.18 and 2.06, respectively.The median (interquartile range; IQR) t 1/2eff for LCPT at day 14 of dosing was 48.4 (37.4-77.9) hours, whereas the t 1/2z was 20.3 (17.6-22.9) hours. For IR-Tac, the median (IQR) t 1/2eff and t 1/2z on day 14 were 12.5 (8.8-23.0) hours and 12.2 (9.2-15.7) hours, respectively. CONCLUSIONS: Consistent with its prolonged release of tacrolimus, LCPT demonstrated a higher accumulation ratio and a longer t 1/2eff compared with IR-Tac. These findings underscore the pharmacokinetic differences between different drug formulations of the same moiety and may help inform dose adjustments for LCPT in kidney transplantation.

There remains an urgent need for expanded genomics training in undergraduate medical education, especially as genetic and genomic assessments become increasingly important in primary care and routine clinical practice across specialties. Physician trainees continue to report feeling poorly prepared to provide effective consultation or interpretation of genomic test results. Here we report on the development, pilot implementation, and evaluation of an elective offering for pre-clinical medical students called the Sanford Precision Health Scholars Immersive Learning Experience (PHS), which was designed leveraging genetic counseling expertise as one means to address this need. This 9-week course, piloted in Fall 2021 at UC San Diego, afforded students the opportunity to build technical skills and competencies in clinical genomics while identifying, addressing, and engaging with pervasive health disparities in genomics. Interactive exercises focused students learning on strategies for empathic and compassionate patient interactions while supporting the application of concepts and knowledge to future practice. Upon completion of the course, participants reported increases in confidence related to skills required for clinical genomics practice. Drawing on learnings from this pilot implementation, recommendations for refining the program include deepening pedagogical engagement with ethical issues, expanding the offering to trainees across health professions, including pharmacy students, and incorporating an optional experiential learning component. Educational offerings, like PHS, that are designed with the input of genetic counseling expertise may ease pressures on the genetic counseling profession by building a more genomic-literate healthcare workforce that can better support efforts to expand access for patients.

Skeletal muscle has a classic structure function relationship; both skeletal muscle microstructure and architecture are directly related to force generating capacity. Biopsy, the gold standard for evaluating muscle microstructure, is highly invasive, destructive to muscle, and provides only a small amount of information about the entire volume of a muscle. Similarly, muscle fiber lengths and pennation angles, key features of muscle architecture predictive of muscle function, are traditionally studied via cadaveric dissection. Noninvasive techniques such as diffusion magnetic resonance imaging (dMRI) offer quantitative approaches to study skeletal muscle microstructure and architecture. Despite its prevalence in applications for musculoskeletal research, clinical adoption is hindered by a lack of understanding regarding its sensitivity to clinically important biomarkers such as muscle fiber cross-sectional area. This review aims to elucidate how dMRI has been utilized to study skeletal muscle, covering fundamentals of muscle physiology, dMRI acquisition techniques, dMRI modeling, and applications where dMRI has been leveraged to noninvasively study skeletal muscle changes in response to disease, aging, injury, and human performance. LEVEL OF EVIDENCE: 5 TECHNICAL EFFICACY: Stage 2.

Anomalous transport of mixed deuterium–tritium plasma in the edge of magnetic fusion reactors is investigated using numerical solutions of resistive drift wave turbulence model equations, including finite Larmor radius effects, that are derived within the generalized Hasegawa–Wakatani framework. The anomalous cross field diffusivities of deuterium and tritium are compared in turbulence regimes with different values of the electron adiabaticity parameter controlling the existence of zonal flow. The dependence of the tritium-to-deuterium diffusivity ratio on the deuterium and tritium densities and the logarithmic density gradients is analyzed, and a scaling relation is obtained.

Disulfide bonds are ubiquitous molecular motifs that influence the tertiary structure and biological functions of many proteins. Yet, it is well known that the disulfide bond is photolabile when exposed to ultraviolet C (UVC) radiation. The deep-UV-induced S─S bond fragmentation kinetics on very fast timescales are especially pivotal to fully understand the photostability and photodamage repair mechanisms in proteins. In 1,2-dithiane, the smallest saturated cyclic molecule that mimics biologically active species with S─S bonds, we investigate the photochemistry upon 200-nm excitation by femtosecond time-resolved x-ray scattering in the gas phase using an x-ray free electron laser. In the femtosecond time domain, we find a very fast reaction that generates molecular fragments with one and two sulfur atoms. On picosecond and nanosecond timescales, a complex network of reactions unfolds that, ultimately, completes the sulfur dissociation from the parent molecule.

Development and function of an organism depend on coordinated inter-tissue interaction. How such interactions are maintained during tissue renewal and reorganization remains poorly understood. Here, we find that Caenorhabditis elegans BEN domain transcription factor LIN-14 is required in epidermis for maintaining the position of motor neurons and muscles during developmental tissue reorganization. lin-14 loss of function (lf) mutants display highly penetrant ventral neuromuscular mispositioning. These defects arise post-embryonically during first larval (L1) stage as the maturing epidermis replaces the embryonic ventral epidermis. Tissue-specific and temporally controlled depletion experiments indicate LIN-14 acts within the epidermis for ventral neuromuscular positioning. lin-14(lf) mutants show defects in formation of epidermis-muscle attachment complex hemidesmosomes in the maturing ventral epidermis, leading to detachment of muscles and motor neurons as well as movement defects. Our findings reveal a cell non-autonomous role for LIN-14 in coordinating inter-tissue interaction and neuromuscular positioning during epidermal maturation.