Effect Of Exercise Training On Endothelium-Dependent Vasodilation In Cerebral Arteries

Endothelial function and expression of endothlelial nitric oxide synthase (eNOS) have been shown to increase with exercise training in the peripheral vasculature. However, the effect of exercise training on endothelial function in the cerebral vasculature is poorly understood. PURPOSE: The purpose of this study was to determine the effect of exercise training on endothelium-dependent vasodilation of large cerebral arteries. METHODS: Three-month-old male Fischer 344 rats were assigned to either a sedentary (SED, n=4) or exercise-trained (ET, n=4) group. ET rats ran on a motorized rodent treadmill 60 min/day at 15 m/min (15 incline), 5 d/wk for 10 wk. Posterior communicating arteries (PCoA) were isolated from the brain of both SED and ET rats. The isolated arteries were cannulated and pressurized to 90 cm H2O via hydrostatic reservoirs. Luminal diameter changes were determined in response to the endothelium-dependent vasodilator, Bradykinin (BK) (10-13 – 10-7 M) and the direct vascular smooth muscle dilator, sodium nitroprusside (SNP, 10-10 – 10-4 M). RESULTS: Responsiveness to the endothelium-dependent vasodilator BK was enhanced in PCoA of ET rats compared to SED rats, whereas responsiveness to the endothelium-independent vasodilator SNP was not different between PCoA of SED and ET rats. CONCLUSION: These data demonstrate that exercise training is associated with enhanced endothelium-mediated vasodilation in PCoA of young rats, whereas vascular smooth muscle responsiveness of PCoA is unaffected by exercise training

Effects Of Aging On Endothelium-Dependent Vasodilation In Cerebral Arteries

Regional cerebral blood flow (CBF) decreases with aging. This reduction may be due to a diminished endothelium-dependent vasodilation in large cerebral arteries with aging in the absence of disease. The posterior communicating arteries (PCoA) supply blood flow to the midbrain areas where age-related regional decreases in blood flow have been observed. Furthermore, the PCoA appear to be clinically relevant in age-related cerebrovascular disorders. However, age-related changes in the vasoreactivity of PCoA have not been investigated in the absence of disease. The purpose of this study was to determine the effect of aging on endothelium-dependent vasodilation of PCoA in rats. Posterior communicating arteries (PCoA) were isolated from the brain of 4 month old (n = 4) and 24 month old (n = 4) male Fischer 344 rats. The isolated arteries were cannulated and pressurized to 90 cm H2O via hydrostatic reservoirs. Luminal diameter changes were determined in response to the endothelium-dependent vasodilator, Bradykinin (BK) (10-13 – 10-7 M) and the direct vascular smooth muscle dilator, sodium nitroprusside (SNP, 10-10 – 10-4 M). Responsiveness to the endothelium-dependent vasodilator BK was diminished in PCoA of aged rats compared to young rats, whereas responsiveness to the endothelium-independent vasodilator SNP was not different between PCoA of young and old rats. These data demonstrate that aging is associated with diminished endothelium-dependent vasodilation in PCoA, whereas vascular smooth muscle responsiveness remains intact. Thus, regional age-related reductions in cerebral blood flow may be related to diminished endothelium-dependent vasodilation in PCoA

Factors controlling bed and bank erosion in the Illgraben (CH)

Debris flows can grow greatly in size and hazardous potential by eroding bed and bank materials. However, erosion mechanisms are poorly understood because debris flows are complex hybrids between a fluid flow and a moving mass of colliding particles, bed erodibility varies between events, and field measurements are hard to obtain. Here, we (i) quantify the spatio-temporal patterns of erosion and deposition and (ii) identify the key controls on debris-flow erosion in the Illgraben (CH). We use a dataset that combines information on flow properties, antecedent rainfall, and bed and bank erosion for 13 debris flows that occurred between 2019 and 2021. We show that spatio-temporal patterns of erosion and deposition in natural debris-flow torrents can be highly variable and dynamic, and we identify a memory effect where erosion is strong at locations of strong deposition during previous flows and vice versa. We find that flow conditions and antecedent rainfall (affecting bed wetness) jointly control debris-flow erosion. We find statistically significant correlations between channel erosion/deposition and a wide range of flow conditions, including frontal flow depth, velocity, and discharge, and flow volume, cumulative shear stress and seismic energy, as well as antecedent rainfall. Overall, flow conditions describing the cumulative forces exerted at the bed during an event, such as cumulative shear stress and flow volume, best explain erosion. A shear-stress approach accounting for bed erodibility may therefore be applicable for modelling and predicting debris-flow erosion. This work can provide input for model development by identifying correlations of flow and bed conditions with erosion that models should oblige

The validity and utility of violence risk assessment tools to predict patient violence in acute care settings: An integrative literature review

To examine risk assessment tools to predict patient violence in acute care settings. An integrative review of the literature. Five electronic databases – CINAHL Plus, MEDLINE, OVID, PsycINFO, and Web of Science were searched between 2000 and 2018. The reference list of articles was also inspected manually. The PICOS framework was used to refine the inclusion and exclusion of the literature, and the PRISMA statement guided the search strategy to systematically present findings. Forty-one studies were retained for review. Three studies developed or tested tools to measure patient violence in general acute care settings, and two described the primary and secondary development of tools in emergency departments. The remaining studies reported on risk assessment tools that were developed or tested in psychiatric inpatient settings. In total, 16 violence risk assessment tools were identified. Thirteen of them were developed to assess the risk of violence in psychiatric patients. Two of them were found to be accurate and reliable to predict violence in acute psychiatric facilities and have practical utility for general acute care settings. Two assessment tools were developed and administered in general acute care, and one was developed to predict patient violence in emergency departments. There is no single, user-friendly, standardized evidence-based tool available for predicting violence in general acute care hospitals. Some were found to be accurate in assessing violence in psychiatric inpatients and have potential for use in general acute care, require further testing to assess their validity and reliability

String Thermalization at a Black Hole Horizon

Susskind has recently shown that a relativistic string approaching the event horizon of a black hole spreads in both the transverse and longitudinal directions in the reference frame of an outside observer. The transverse spreading can be described as a branching diffusion of wee string bits. This stochastic process provides a mechanism for thermalizing the quantum state of the string as it spreads across the stretched horizon.Comment: 14 pages, latex, SU-ITP-94-4, NSF-ITP-94-1

HI in four star-forming low-luminosity E/S0 and S0 galaxies

We present HI data cubes of four low-luminosity early-type galaxies which are currently forming stars. These galaxies have absolute magnitudes in the range M_B=-17.9 to -19.9 (H_o=50 km/s/Mpc). Their HI masses range between a few times 10^8 and a few times 10^9 M_sun and the corresponding values for M_HI/L_B are between 0.07 and 0.42, so these systems are HI rich for their morphological type. In all four galaxies, the HI is strongly centrally concentrated with high central HI surface densities, in contrast to what is typically observed in more luminous early-type galaxies. In two galaxies (NGC 802 and ESO 118-G34), the kinematics of the HI suggests that the gas is in a strongly warped disk, which we take as evidence for recent accretion of HI. In the other two galaxies (NGC 2328 and ESO 027-G21) the HI must have been part of the systems for a considerable time. The HI properties of low-luminosity early-type galaxies appear to be systematically different from those of many more luminous early-type galaxies, and we suggest that these differences are due to a different evolution of the two classes. The star formation history of these galaxies remains unclear. Their UBV colours and Halpha emission-line strengths are consistent with having formed stars at a slowly-declining rate for most of the past 10^10 years. However, the current data do not rule out a small burst of recent star formation overlaid on an older stellar population.Comment: To appear in AJ, LateX, figures in gif format, paper also available at http://www.nfra.nl/~morganti/LowLu

Factors controlling bed and bank erosion in the Illgraben (CH)

Debris flows can grow greatly in size and hazardous potential by eroding bed and bank materials. However, erosion mechanisms are poorly understood because debris flows are complex hybrids between a fluid flow and a moving mass of colliding particles, bed erodibility varies between events, and field measurements are hard to obtain. Here, we (i) quantify the spatio-temporal patterns of erosion and deposition and (ii) identify the key controls on debris-flow erosion in the Illgraben (CH). We use a dataset that combines information on flow properties, antecedent rainfall, and bed and bank erosion for 13 debris flows that occurred between 2019 and 2021. We show that spatio-temporal patterns of erosion and deposition in natural debris-flow torrents can be highly variable and dynamic, and we identify a memory effect where erosion is strong at locations of strong deposition during previous flows and vice versa. We find that flow conditions and antecedent rainfall (affecting bed wetness) jointly control debris-flow erosion. We find statistically significant correlations between channel erosion/deposition and a wide range of flow conditions, including frontal flow depth, velocity, and discharge, and flow volume, cumulative shear stress and seismic energy, as well as antecedent rainfall. Overall, flow conditions describing the cumulative forces exerted at the bed during an event, such as cumulative shear stress and flow volume, best explain erosion. A shear-stress approach accounting for bed erodibility may therefore be applicable for modelling and predicting debris-flow erosion. This work can provide input for model development by identifying correlations of flow and bed conditions with erosion that models should oblige

Unravelling the immune signature of Plasmodium falciparum transmission-reducing immunity

Infection with Plasmodium can elicit antibodies that inhibit parasite survival in the mosquito, when they are ingested in an infectious blood meal. Here, we determine the transmission-reducing activity (TRA) of naturally acquired antibodies from 648 malaria-exposed individuals using lab-based mosquito-feeding assays. Transmission inhibition is significantly associated with antibody responses to Pfs48/45, Pfs230, and to 43 novel gametocyte proteins assessed by protein microarray. In field-based mosquito-feeding assays the likelihood and rate of mosquito infection are significantly lower for individuals reactive to Pfs48/45, Pfs230 or to combinations of the novel TRA-associated proteins. We also show that naturally acquired purified antibodies against key transmission-blocking epitopes of Pfs48/45 and Pfs230 are mechanistically involved in TRA, whereas sera depleted of these antibodies retain high-level, complement-independent TRA. Our analysis demonstrates that host antibody responses to gametocyte proteins are associated with reduced malaria transmission efficiency from humans to mosquitoes

The limitations of some European healthcare databases for monitoring the effectiveness of Pregnancy Prevention Programmes as risk minimisation measures

Purpose: Pregnancy prevention programmes (PPPs) exist for some medicines known to be highly teratogenic. It is increasingly recognised that the impact of these risk minimisation measures requires periodic evaluation. This study aimed to assess the extent to which some of the data needed to monitor the effectiveness of PPPs may be present in European healthcare databases. Methods: An inventory was completed for databases contributing to EUROmediCAT capturing pregnancy and prescription data in Denmark, Norway, the Netherlands, Italy (Tuscany/Emilia Romagna), Wales and the rest of the UK, to determine the extent of data collected that could be used to evaluate the impact of PPPs. Results: Data availability varied between databases. All databases could be used to identify the frequency and duration of prescriptions to women of childbearing age from primary care, but there were specific issues with availability of data from secondary care and private care. To estimate the frequency of exposed pregnancies, all databases could be linked to pregnancy data, but the accuracy of timing of the start of pregnancy was variable, and data on pregnancies ending in induced abortions were often not available. Data availability on contraception to estimate compliance with contraception requirements was variable and no data were available on pregnancy tests. Conclusion: Current electronic healthcare databases do not contain all the data necessary to fully monitor the effectiveness of PPP implementation, and thus, special data collection measures need to be instituted.</p

Prescribing of antidiabetic medicines before, during and after pregnancy:a study in seven European regions

Aim: To explore antidiabetic medicine prescribing to women before, during and after pregnancy in different regions of Europe.Methods: A common protocol was implemented across seven databases in Denmark, Norway, The Netherlands, Italy (Emilia Romagna/Tuscany), Wales and the rest of the UK. Women with a pregnancy starting and ending between 2004 and 2010, (Denmark, 2004-2009; Norway, 2005-2010; Emilia Romagna, 2008-2010), which ended in a live or stillbirth, were identified. Prescriptions for antidiabetic medicines issued (UK) or dispensed (non-UK) during pregnancy and/or the year before or year after pregnancy were identified. Prescribing patterns were compared across databases and over calendar time.Results: 1,082,673 live/stillbirths were identified. Pregestational insulin prescribing during the year before pregnancy ranged from 0.27% (CI95 0.25-0.30) in Tuscany to 0.45% (CI95 0.43-0.47) in Norway, and increased between 2004 and 2009 in all countries. During pregnancy, insulin prescribing peaked during the third trimester and increased over time; third trimester prescribing was highest in Tuscany (2.2%) and lowest in Denmark (0.5%). Of those prescribed an insulin during pregnancy, between 50.5% in Denmark and 88.8% in the Netherlands received an insulin analogue alone or in combination with human insulin, this proportion increasing over time. Oral products were mainly metformin and prescribing was highest in the 3 months before pregnancy. Metformin use during pregnancy increased in some countries. Conclusion: Pregestational diabetes is increasing in many areas of Europe. There is considerable variation between and within countries in the choice of medication for treating pregestational diabetes in pregnancy, including choice of insulin analogues and oral antidiabetics, and very large variation in the diagnosis and treatment of gestational diabetes despite international guidelines. <br/