Blood pressure and sodium: association with MRI markers in cerebral small vessel disease

Dietary salt intake and hypertension are associated with increased risk of cardiovascular disease including stroke. We aimed to explore the influence of these factors, together with plasma sodium concentration, in cerebral small vessel disease (SVD). In all, 264 patients with nondisabling cortical or lacunar stroke were recruited. Patients were questioned about their salt intake and plasma sodium concentration was measured; brain tissue volume and white-matter hyperintensity (WMH) load were measured using structural magnetic resonance imaging (MRI) while diffusion tensor MRI and dynamic contrast-enhanced MRI were acquired to assess underlying tissue integrity. An index of added salt intake (P = 0.021), pulse pressure (P = 0.036), and diagnosis of hypertension (P = 0.0093) were positively associated with increased WMH, while plasma sodium concentration was associated with brain volume (P = 0.019) but not with WMH volume. These results are consistent with previous findings that raised blood pressure is associated with WMH burden and raise the possibility of an independent role for dietary salt in the development of cerebral SVD

Activation of Thiazide-Sensitive Co-Transport by Angiotensin II in the cyp1a1-Ren2 Hypertensive Rat

Transgenic rats with inducible expression of the mouse Ren2 gene were used to elucidate mechanisms leading to the development of hypertension and renal injury. Ren2 transgene activation was induced by administration of a naturally occurring aryl hydrocarbon, indole-3-carbinol (100 mg/kg/day by gastric gavage). Blood pressure and renal parameters were recorded in both conscious and anesthetized (butabarbital sodium; 120 mg/kg IP) rats at selected time-points during the development of hypertension. Hypertension was evident by the second day of treatment, being preceded by reduced renal sodium excretion due to activation of the thiazide-sensitive sodium-chloride co-transporter. Renal injury was evident after the first day of transgene induction, being initially limited to the pre-glomerular vasculature. Mircoalbuminuria and tubuloinsterstitial injury developed once hypertension was established. Chronic treatment with either hydrochlorothiazide or an AT1 receptor antagonist normalized sodium reabsorption, significantly blunted hypertension and prevented renal injury. Urinary aldosterone excretion was increased ∼20 fold, but chronic mineralocorticoid receptor antagonism with spironolactone neither restored natriuretic capacity nor prevented hypertension. Spironolactone nevertheless ameliorated vascular damage and prevented albuminuria. This study finds activation of sodium-chloride co-transport to be a key mechanism in angiotensin II-dependent hypertension. Furthermore, renal vascular injury in this setting reflects both barotrauma and pressure-independent pathways associated with direct detrimental effects of angiotensin II and aldosterone

Mortality and pulmonary complications in patients undergoing surgery with perioperative SARS-CoV-2 infection: an international cohort study

Background: The impact of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on postoperative recovery needs to be understood to inform clinical decision making during and after the COVID-19 pandemic. This study reports 30-day mortality and pulmonary complication rates in patients with perioperative SARS-CoV-2 infection. Methods: This international, multicentre, cohort study at 235 hospitals in 24 countries included all patients undergoing surgery who had SARS-CoV-2 infection confirmed within 7 days before or 30 days after surgery. The primary outcome measure was 30-day postoperative mortality and was assessed in all enrolled patients. The main secondary outcome measure was pulmonary complications, defined as pneumonia, acute respiratory distress syndrome, or unexpected postoperative ventilation. Findings: This analysis includes 1128 patients who had surgery between Jan 1 and March 31, 2020, of whom 835 (74·0%) had emergency surgery and 280 (24·8%) had elective surgery. SARS-CoV-2 infection was confirmed preoperatively in 294 (26·1%) patients. 30-day mortality was 23·8% (268 of 1128). Pulmonary complications occurred in 577 (51·2%) of 1128 patients; 30-day mortality in these patients was 38·0% (219 of 577), accounting for 81·7% (219 of 268) of all deaths. In adjusted analyses, 30-day mortality was associated with male sex (odds ratio 1·75 [95% CI 1·28–2·40], p\textless0·0001), age 70 years or older versus younger than 70 years (2·30 [1·65–3·22], p\textless0·0001), American Society of Anesthesiologists grades 3–5 versus grades 1–2 (2·35 [1·57–3·53], p\textless0·0001), malignant versus benign or obstetric diagnosis (1·55 [1·01–2·39], p=0·046), emergency versus elective surgery (1·67 [1·06–2·63], p=0·026), and major versus minor surgery (1·52 [1·01–2·31], p=0·047). Interpretation: Postoperative pulmonary complications occur in half of patients with perioperative SARS-CoV-2 infection and are associated with high mortality. Thresholds for surgery during the COVID-19 pandemic should be higher than during normal practice, particularly in men aged 70 years and older. Consideration should be given for postponing non-urgent procedures and promoting non-operative treatment to delay or avoid the need for surgery. Funding: National Institute for Health Research (NIHR), Association of Coloproctology of Great Britain and Ireland, Bowel and Cancer Research, Bowel Disease Research Foundation, Association of Upper Gastrointestinal Surgeons, British Association of Surgical Oncology, British Gynaecological Cancer Society, European Society of Coloproctology, NIHR Academy, Sarcoma UK, Vascular Society for Great Britain and Ireland, and Yorkshire Cancer Research

Cliff erosion and coastal change, mid Canterbury.

The mid Canterbury coast has been largely neglected in the coastal research of the South Island's East Coast. This thesis investigates cliff erosion and coastal change in mid Canterbury. The mid Canterbury coast is comprised of mixed sand and gravel beaches with unconsolidated alluvium cliffs landward of the beaches. The average erosion rate of the cliffs is 0.43m.y( 1 • This rate masks spatial and temporal variations in cliff erosion rates. Erosion at the northern section of the study area is 0.7m.y( 1 faster than erosion at the southern end. In the long-term (15 years) cliff height is the major controlling factor on the spatial variations of cliff erosion (r = 0.733). Beach volume controls short-term (1 year) spatial variations of cliff erosion (r = -0.774). Coastal storm frequency significantly controls temporal variations of cliff erosion (r = 0.635). Erosion of the mid Canterbury cliffs yields 228,339m3 .y( 1 to the coast. Longshore sediment transport is predominantly in a northward direction and provides a net sediment quantity of 40,645m3 .y( 1 • The mid Canterbury coast is bisected by two major rivers, the Ashburton and Rangitata. Their specific sediment yields are among the largest in the world. Sediment yields of beach forming material (coarse sands and gravels) are much lower supplying 25,000 and 28,000m3 .yr- 1 of sediment to the coast. The mid Canterbury coast has a sediment budget deficit of 27,500m3 .yr- 1 • Major sources of sediment to the mid Canterbury coast are cliff erosion (70 per cent), river transport (17 per cent) and longshore sediment transport (13 per cent). Major sediment sinks include offshore transport through abrasion (76.8 per cent) and longshore sediment transport (23.2 per cent). The large amount of sediment lost through abrasion suggests that sediment, once it arrives on the coast has a short 'life span' before it is ground up. Total beach sediment volume varies significantly from year to year but is losing 27,500m3 .yr- 1 of sediment on average

Investigating the reliability of digital templating for hip hemiarthroplasty for neck of femur fracture

Aims and objectives: Hip hemiarthroplasty is commonly performed for intracapsular neck of femur fractures in the elderly. Digital templating is commonly used in elective arthroplasty however its use is less well established in the setting of trauma. This study aims to evaluate the efficacy of digital templating in hip hemiarthroplasty for stem-femur compatibility and head size. Materials and methods: Retrospective cohort study using prospective departmental database. Preoperative radiographs and templating reports were reviewed along with operative notes. The digitally templated implant type and size was compared with the actual implant as documented in the operation note. Results: 90 consecutive patients identified. 42 patients (46.6 %) had preoperative templating performed. 4 patients (9.5 %) of those templated preoperatively had an intraoperative conversion to bipolar system due to stem-femur incompatibility. There were no incidences of stem-femur incompatibility in patients that did not have preoperative templating. Head size was correctly templated in 20 % of cases and 75 % within 2 head sizes. Conclusion: Digital templating for the Thompson hemiarthroplasty stem does not reliably predict stem-femur compatibility or implant head size

Optimization of sampling for the temporal monitoring of Technetium-99 in the Arctic marine environment

Monitoring of the marine environment for radioactivity, for both radiological protection and for oceanographic purposes, remains an expensive and labour intensive activity due to the large sample volumes needed and the complex and lengthy analytical procedures required to measure low levels of contamination. Because of this, some consideration must be given to the design of sampling plans to ensure effective and efficient sampling that can be defended on the basis of scientific rationale. This article tests the hypothesis that geostatistical techniques may prove of use in the optimisation and design of sampling regimes for the monitoring of temporal fluctuations in the levels of technetium at a location in the Norwegian Arctic marine environment. The level of temporal correlation exhibited by two relevant time series was investigated and the information used to observe the effect of sampling frequency on the production of monthly estimates of activity of technetium in both seawater and seaweed. The results indicate that reduced sampling frequency allows production of estimates that acceptably replicate the actual data and that use of geostatistical procedures may offer advantages in the planning of monitoring systems for marine radioactivity. The use of an oceanographic model was also investigated as a means of assessing the temporal correlation prior to actual sampling, an approach that may offer significant advantages by reducing the need to have lengthy time series prior to designing sampling regimes

Loading rat heart myocytes with Mg(2+) using low-[Na(+)] solutions

The objective of our study was to investigate how Mg(2+) enters mammalian cardiac cells. During this work, we found evidence for a previously undescribed route for Mg(2+) entry, and now provide a preliminary account of its properties. Changes in Mg(2+) influx into rat ventricular myocytes were deduced from changes in intracellular ionized Mg(2+) concentration ([fMg(2+)](i)) measured from the fluorescence of mag-fura-2 loaded into isolated cells. Superfusion of myocytes at 37°C with Ca(2+)-free solutions with both reduced [Na(+)] and raised [Mg(2+)] caused myocytes to load with Mg(2+). Uptake was seen with solutions containing 5 mm Mg(2+) and 95 mm Na(+), and increased linearly with increasing extracellular [Mg(2+)] or decreasing extracellular [Na(+)]. It was very sensitive to temperature (Q(10) > 9, 25–37°C), was observed even in myocytes with very low Na(+) contents, and stopped abruptly when external [Na(+)] was returned to normal. Uptake was greatly reduced by imipramine or KB-R7943 if these were added when [fMg(2+)](i) was close to the physiological level, but was unaffected if they were applied when [fMg(2+)](i) was above 2 mm. Uptake was also reduced by depolarizing the membrane potential by increasing extracellular [K(+)] or voltage clamp to 0 mV. We suggest that initial Mg(2+) uptake may involve several transporters, including reversed Na(+)–Mg(2+) antiport and, depending on the exact conditions, reversed Na(+)–Ca(2+) antiport. The ensuing rise of [fMg(2+)](i), in conjunction with reduced [Na(+)], may then activate a new Mg(2+) transporter that is highly sensitive to temperature, is insensitive to imipramine or KB-R7943, but is inactivated by depolarization