The mechanics and regulation of rat aortic smooth muscle contraction: implications of cytoskeletal remodeling, protein phosphorylations, and microtubule-based kinase transport

The exact nature of the mechanisms and the regulation of vascular smooth muscle contraction is not well understood. To better understand these processes, we examined two systems involved in smooth muscle contraction, the cytoskeleton and the protein kinases. In order to study the role of the cytoskeleton in smooth muscle contraction, we examined the contractile and mechanical effects of cytoskeleton disruption. We found that the relationship between passive tension applied to aortic rings and the resulting increase in tissue length was nearly linear over the range of 1 g to 15 g. However, even with increasing tissue length, within the range of 1 g to 10 g passive tension, the total active force generated upon stimulation was not significantly changed. These observations emphasize the great flexibility of the mechanism(s) underlying the contractile response of vascular smooth muscle with regard to changes in tissue preload and length. Neither the blockade of microtubule polymerization by colchicine nor actin polymerization by cytochalasin B significantly changed the slope of the tissue length-passive tension preload curve indicating no effect on the tissues\u27 capacity to stretch at a given preload. With stimulation of the tissue at different levels of stretch, colchicine caused an increase in the initial fast component of active tension development, but partially blocked the secondary slow rise in tension. Cytochalasin B dramatically reduced the total contractile response at each preload studied, and this effect was confined almost exclusively to the secondary slow increase in tension. When tissues were cooled to cause complete dissolution of the microtubule network and then warmed in the presence of colchicine to prevent repolymerization of both the active and stable populations of microtubules, there was also a significant reduction in the slow component of contraction with no effect on the fast response. The partial blockade of synthesis of the microtubule-associated motor protein kinesin by application of an antisense oligonucleotide to aortae in situ or to aortic rings in tissue culture significantly reduced the contractile response to potassium depolarization. These results suggest that the microtubules and the actin filaments of the cytoskeleton play an active role in slow force development as opposed to a solely passive role based on the effect of the static, structural properties of these filaments on mechanical resistance. We propose that a tension-bearing element of the actin-containing cytoskeleton undergoes remodeling to adjust tension within the system. The microtubules could act through either the direct action of kinesin-mediated intracytoskeletal interactions in force development that involve a remodeling of the tension-bearing elements of the cytoskeleton or through the directed movement of the molecules involved in the transduction process. Because the cytoskeleton and the protein kinases of smooth muscle are intimately linked, we examined the potential role of protein kinases in vascular smooth muscle contraction. We began by assessing the effects of a panel of specific kinase inhibitors on smooth muscle contraction. We found reductions in contraction with inhibition of myosin light chain kinase (MLCK), calcium-dependent calmodulin kinase (CaMKII), mitogen activated protein (MAP) kinase, and protein kinase C (PKC). Protein kinase C (PKC) is translocated in an isoform-specific manner to distinct subcellular locations after stimulation of cells. It is thought that translocation is essential for PKC activation and that cellular localization underlies the PKC isoform-specific phosphorylation of substrate in the intact cell that is largely absent in in vitro assays. In the present studies, it was shown using Western blot analysis that the ratio of particulate to cytosolic PKC-α was reduced in rat aortic segments treated with colchicine to disrupt microtubular structure prior to stimulation with phorbol 12, 13 dibutyrate (PDB). Subsequent studies using laser confocal microscopy revealed that within thirty seconds after stimulation with PDB, PKC-α in cultured rat aortic smooth muscle cells changed from a diffuse cytoplasmic distribution to a highly structured filamentous pattern of staining. Dual immunostaining further indicated that the stimulation-induced filamentous pattern was due to colocalization of PKC-α with cell microtubules. At longer time intervals after PDB stimulation, PKC-α was observed to translocate to the perinuclear region of the cell. Disruption of the microtubular but not the actin-containing component of the cytoskeleton blocked the translocation of PKC-α to the perinuclear membrane. It was further shown that slow tension development, which has been reported to be selectively blocked by PKC antagonists in vascular smooth muscle, was also blocked by disruption of the cell microtubules. The results provide further evidence for the involvement of PKC in slow tension development by smooth muscle and indicate that PKC translocation may involve microtubular transport

Viability of Hunting as a Means of Wild Hog Population Management on Federal Property

The Big South Fork National River and Recreation Area allows hunter to purchase permits and hunt wild hogs on property with the intention of curbing increases in wild hog populations. In order to assess outcomes of the wild hog hunting permit program, researchers collaborated with site managers to develop protocol and solicit information from permit holders regarding number of animals seen and harvested, sex of animals harvested, geographic areas hunted, length and number of hunts, and open qualitative feedback regarding the program. All permit holders agreeing to be contacted during permit registration were called with 37.57% (N=65) of permit holder completing the telephone survey. While more hogs were seen than harvested, the total harvested hogs was 52. Results indicate hunting is not a viable option for population management in and of itself, as the number if wild hogs harvested was minimal. A longitudinal study is necessary to overcome case study (single year) limitations, such as weather, hunter economics, herd movement, herd reproduction and so forth. Salient variables may warrant consideration, including marketing of permit program, number of hunters within acceptable driving distance to hunting location, and much more. Herd management initiatives beyond hunting may be considered when necessary to control wild hog populations

Physical activity levels in female rheumatoid arthritis patients on long term anti-TNF therapy compared to patients with active rheumatoid disease and healthy controls. [Abstract]

Background: Anti-TNF therapy has revolutionised the management of rheumatoid arthritis (RA) with rapid and sustained improvements in pain, function and quality of life. However, we do not know how this impacts upon habitual daily physical activity and whether treated patients attain activity levels seen in healthy controls. This study aimed to compare the physical activity levels of patients whose RA was well controlled on long-term anti-TNF therapy to RA patients with active arthritis and non-RA controls. Methods: Participants were patients on anti-TNF for more than two years (tRA) with DAS3.2 (aRA) and healthy controls (C), matched for age and BMI. Physical activity was assessed using the Actigraph GT3x+ accelerometer, worn throughout waking hours for seven days to determine time spent in light activity, moderate to vigorous physical activity (MVPA) and sedentary time. The International Physical Activity Questionnaire (IPAQ) was also completed. Groups were compared using analysis of variance with Bonferroni post hoc tests; Kruskal-Wallis or Mann-Whitney U- test as appropriate. Results: RA disease duration was significantly greater in tRA than aRA. Groups did not differ significantly in age, height, weight or body mass index (Table). Daily step count was significantly lower in aRA than tRA and C. Sedentary time (as a proportion of wear time) was significantly greater in aRA than tRA, whilst the reverse was true for light activity time. MVPA time was significantly lower in both RA groups than in controls. IPAQ questionnaires demonstrated significant differences between groups, with substantially higher values in C than RA groups in total METs and MET-minutes per week in domestic and garden, leisure, walking activities as well as total moderate and vigorous activities. RA patients had lower moderate to vigorous activity time than controls, regardless of treatment. aRA had lower light activity time, and more sedentary time, than tRA Conclusion: Moderate to vigorous physical activity should be promoted in all RA patients as even those with well controlled disease exhibit a deficit in comparison to control

HumMod: A Modeling Environment for the Simulation of Integrative Human Physiology

Mathematical models and simulations are important tools in discovering key causal relationships governing physiological processes. Simulations guide and improve outcomes of medical interventions involving complex physiology. We developed HumMod, a Windows-based model of integrative human physiology. HumMod consists of 5000 variables describing cardiovascular, respiratory, renal, neural, endocrine, skeletal muscle, and metabolic physiology. The model is constructed from empirical data obtained from peer-reviewed physiological literature. All model details, including variables, parameters, and quantitative relationships, are described in Extensible Markup Language (XML) files. The executable (HumMod.exe) parses the XML and displays the results of the physiological simulations. The XML description of physiology in HumMod's modeling environment allows investigators to add detailed descriptions of human physiology to test new concepts. Additional or revised XML content is parsed and incorporated into the model. The model accurately predicts both qualitative and quantitative changes in clinical and experimental responses. The model is useful in understanding proposed physiological mechanisms and physiological interactions that are not evident, allowing one to observe higher level emergent properties of the complex physiological systems. HumMod has many uses, for instance, analysis of renal control of blood pressure, central role of the liver in creating and maintaining insulin resistance, and mechanisms causing orthostatic hypotension in astronauts. Users simulate different physiological and pathophysiological situations by interactively altering numerical parameters and viewing time-dependent responses. HumMod provides a modeling environment to understand the complex interactions of integrative physiology. HumMod can be downloaded at http://hummod.or

Physical activity and sedentary behavior in women with rheumatoid arthritis: a comparison of patients with low and high disease activity and healthy controls

Objective: In rheumatoid arthritis (RA) patients, low levels of physical activity (PA) and high levels of sedentary behavior (SB) may play a role in enhancing cardiovascular risk. We do not know how long-term control of disease activity impacts upon daily PA levels and if treated patients attain PA levels seen in healthy controls. We therefore compared habitual levels of PA and SB between female RA patients with low disease activity achieved by anti-tumor necrosis factor (TNF) therapy, those with active arthritis (aRA) and non-RA controls. Methods: We carried out a cross-sectional comparison of 40 RA patients on anti-TNF therapy for >2 years with DAS28<3.2 (tRA), 32 patients on conventional disease modifying anti-rheumatic drugs with DAS28>3.2 (aRA) and 34 healthy controls (C) with the groups matched for age and body mass index. PA was assessed using the ActiGraph accelerometer to determine step count and time spent in moderate-to-vigorous physical activity (MVPA), light activity and sedentary time. Results: Daily step count was 72% higher in tRA and 40% higher in C in comparison to aRA (p<0.01). Sedentary time (as a proportion of wear time) was 10% less in tRA than aRA (p=0.03), while light activity time was 18% higher (p=0.014). Both RA groups had 40% lower MVPA time than C (p=0.001). Only half of either RA group fulfilled current WHO guidelines for PA compared with 82% of controls. Conclusion: RA patients who had long-term disease suppression were more physically active with less SB compared to RA patients with active disease. They had similar light PA and SB to controls although lower MVPA. Behavioral change interventions are likely to be needed in order to restore moderate exercise, further reduce SB and to meet guidelines for daily PA

Impact of the COVID‐19 pandemic on Creutzfeldt–Jakob disease surveillance and patient care in the United Kingdom

BACKGROUND AND PURPOSE: Creutzfeldt–Jakob disease (CJD) is lethal and transmissible. We assessed the impact of the COVID‐19 pandemic on UK CJD surveillance. We hypothesized that (i) disruptions prolonged diagnostic latency; (ii) autopsy rates declined; and (iii) COVID‐19 infection negatively affected diagnosis, care, and survival. METHODS: We retrospectively investigated the first year of the pandemic, using the preceding year as a comparator, quantifying numbers of individuals assessed by the UK National CJD Research & Surveillance Unit for suspected CJD, time to diagnosis, disease duration, and autopsy rates. We evaluated the impact of COVID‐19 status on diagnosis, care, and survival in CJD. RESULTS: A total of 148 individuals were diagnosed with CJD in the pandemic (from a total of 166 individuals assessed) compared to 141 in the comparator (from 145 assessed). No differences were identified in disease duration or time to diagnosis. Autopsy rates were unchanged. Twenty individuals had COVID‐19; 60% were symptomatic, and 10% had severe disease. Disruptions in diagnosis and care were frequently identified. Forty percent of COVID‐19‐positive individuals died; however, COVID‐19 status did not significantly alter survival duration in CJD. CONCLUSIONS: The COVID‐19 pandemic has not impacted UK CJD case ascertainment or survival, but diagnostic evaluation and clinical care of individuals have been affected

Incidence and recognition of acute respiratory distress syndrome in a UK intensive care unit.

The reported incidence of ARDS is highly variable (2.5%-19% of intensive care unit (ICU) patients) and varies depending on study patient population used. We undertook a 6-month, prospective study to determine the incidence and outcome of ARDS in a UK adult University Hospital ICU. 344 patients were admitted during the study period, of these 43 (12.5%) were determined to have ARDS. Patients with ARDS had increased mortality at 28 days and 2 years post-diagnosis, and there was under-recognition of ARDS in both medical records and death certificattion. Our findings have implications for critical care resource planning.This is the final version of the article. It first appeared from BMJ Thorax via ://dx.doi.org/10.1136/thoraxjnl-2016-20840

EcoEvo-MAPS: An Ecology and Evolution Assessment for Introductory through Advanced Undergraduates

A new assessment tool, Ecology and Evolution–Measuring Achievement and Progression in Science or EcoEvo-MAPS, measures student thinking in ecology and evolution during an undergraduate course of study. EcoEvo-MAPS targets foundational concepts in ecology and evolution and uses a novel approach that asks students to evaluate a series of predictions, conclusions, or interpretations as likely or unlikely to be true given a specific scenario. We collected evidence of validity and reliability for EcoEvo-MAPS through an iterative process of faculty review, student interviews, and analyses of assessment data from more than 3000 students at 34 associate’s-, bachelor’s-, master’s-, and doctoral-granting institutions. The 63 likely/unlikely statements range in difficulty and target student understanding of key concepts aligned with the Vision and Change report. This assessment provides departments with a tool to measure student thinking at different time points in the curriculum and provides data that can be used to inform curricular and instructional modifications

Sporadic Creutzfeldt-Jakob Disease in the young (50 and below):10-year review of United Kingdom surveillance

INTRODUCTION: Sporadic Creutzfeldt–Jakob Disease (sCJD) is the commonest human prion disease, with a median age of onset of 68 years. We characterise the clinical, investigation, and neuropathological features in young individuals with sCJD using data from UK national CJD surveillance. METHODS: Referrals between 2011 and 2021 were examined, with definite (post-mortem confirmed) or probable sCJD cases included. Clinical features, MRI, EEG, CSF RT-QuIC, 14-3-3, PRNP sequencing and neuropathological findings were examined. We compared younger (≤ 50 years age of onset) with older individuals. Records of Non-sCJD referrals were also reviewed. RESULTS: 46 (4%) young individuals were identified (age at onset 25–50) from 1178 cases. 15 (33%) were autopsy confirmed. Psychiatric disturbance (37% vs 22%, p = 0.02) and headache (11% vs 3%, p = 0.01) at presentation, and longer disease duration (by 1.45 months, 95% CI 0.43–2.79, logrank p = 0.007) were commoner. CSF RT-QuIC showed lower sensitivity (82% vs 93%, p = 0.02). There was no difference in sensitivity of MR brain or CSF 14-3-3. There were no significant co-pathologies in autopsy-confirmed cases. For non-sCJD referrals, 41 cases were of other CJD subtypes, and 7 non-prion diagnoses. CONCLUSIONS: Young-onset sCJD is more likely to present with neuropsychiatric symptoms and headache, longer disease duration, and lower sensitivity of RT-QuIC. These findings may be driven by the underlying molecular subtypes. Our results guide the evaluation of younger individuals presenting with rapidly progressive cognitive, neuropsychiatric, and motor decline, and emphasise the need for additional vigilance for atypical features by clinicians and CJD surveillance programmes worldwide. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00415-022-11467-3