Biology subjects

Harris, J. L.

Publications and source records attributed to Harris, J. L..

3 recordsLinked to original sources

bioRxiv2022

X-ray imaging of 30 year old wine grape wood reveals cumulative impacts of rootstocks on scion secondary growth and harvest index

O_LIAnnual rings from 30 year old vines in a California rootstock trial were measured to determine the effects of 15 different rootstocks on Chardonnay and Cabernet Sauvignon scions. Viticultural traits measuring vegetative growth, yield, berry quality, and nutrient uptake were collected at the beginning and end of the lifetime of the vineyard. C_LIO_LIX-ray Computed Tomography (CT) was used to measure ring widths in 103 vines. Ring width was modeled as a function of ring number using a negative exponential model. Early and late wood ring widths, cambium width, and scion trunk radius were correlated with 27 traits. C_LIO_LIModeling of annual ring width shows that scions alter the width of the first rings but that rootstocks alter the decay thereafter, consistently shortening ring width throughout the lifetime of the vine. The ratio of yield to vegetative growth, juice pH, photosynthetic assimilation and transpiration rates, and stomatal conductance are correlated with scion trunk radius. C_LIO_LIRootstocks modulate secondary growth over years, altering hydraulic conductance, physiology, and agronomic traits. Rootstocks act in similar but distinct ways from climate to modulate ring width, which borrowing techniques from dendrochronology, can be used to monitor both genetic and environmental effects in woody perennial crop species. C_LI

plant biology↗

bioRxiv2021

Sex Differences in Cerebral Edema after Experimental Traumatic Brain Injury

Traumatic brain injury (TBI) is one of the leading causes of death and disability worldwide. Cerebral edema following TBI is known to play a critical role in injury severity and prognosis. In the current study we used multimodal magnetic resonance imaging (MRI) to assess cerebral edema 24 hours after unilateral contusive TBI in male and female rats. We then directly quantified brain water content in the same subjects ex vivo. We found that both males and females had similarly elevated T2 values after TBI compared with sham controls. Apparent diffusion coefficient (ADC) was more variable than T2 and did not show significant injury effects in males or females. Brain water was elevated in male TBI rats compared with sham controls, but there was no difference between female TBI and sham groups. Notably, MRI biomarkers of edema were more closely correlated with brain water in male rats; female rats did not show any relationship between brain water and T2 or ADC. These observations raise questions about the interpretation of radiological findings traditionally interpreted as edema in female TBI patients. A better understanding of sex differences and similarities in the pathophysiology of post-traumatic edema is needed to help improve patient management and the development of effective treatment strategies for men and women.

neuroscience↗

bioRxiv2019

Treatment with β3 adrenergic agonists reverses impaired cardiac myocyte Na+ export and improves severely decompensated heart failure; a clinical application of an experimental finding

BackgroundReported one- and two-year mortality for patients with advanced heart failure (HF) treated medically are ~75% and nearly 100%. In such patients, reversible cellular abnormalities are potential treatment targets and a raised cytosolic Na+ concentration that impairs their myocardial contractility is one potential target. {beta}3 adrenoceptor ({beta}3 AR) agonists stimulate the myocyte Na+-K+ pump. MethodsWe induced severe HF in rabbits by coronary ligation and measured indices of organ congestion after treatment with {beta}3 AR agonists. Na+-K+ pump current was measured in voltage-clamped myocytes isolated from non-infarct myocardium. To assess if {beta}3 ARs might add benefit to optimised guideline-directed medical treatment we report outcomes of giving the {beta}3 AR agonist mirabegron to patients hospitalized with advanced, treatment-refractory stage D HF. ResultsTreatment of rabbits after coronary ligation with {beta}3 AR agonist reversed a decreased myocyte Na+-K+ pump current and significantly reduced organ congestion and prevalence of ascites. Oral treatment with mirabegron rapidly improved signs and symptoms of 9 patients with advanced HF and improvement of [≥]1 NYHA Class was maintained early post-discharge with continued treatment. One patient died from HF at 16 months, 4 died from other causes at 2 - 30 months and 4 remain alive at 38 {+/-} 4 months with NYHA Class II symptoms. ConclusionsParallel {beta}3 AR agonist-induced reversal of Na+-K+ pump inhibition and severe HF in rabbits identify pump inhibition as a treatment target, and changed in-hospital clinical trajectory and post-discharge course more favorable than expected suggest efficacy of mirabegron in advanced human HF.

physiology↗