Moraxella endocarditis following balloon angioplasty of aortic coarctation.
Explore the source record for details and available documents.
Angioplasty, Balloon↗
Biomedical subjects
N Wilson
Publications and source records attributed to N Wilson.
Haemodynamic effect of supraaortic ridge enhancement on the closure mechanism of the aortic valve and its implications in aortic valve repair.
The presence of the sinus of valsalva plays an essential part in the closing mechanism of the aortic valve. High-energy vortices are initiated at the upper limit of each sinus or supraaortic crest, and last during the whole valve closing time. An attempt was made to prove this hypothesis in vivo by intermittent augmentation of each supraaortic ridge. In a series of five dogs without cardiopulmonary bypass, pledgeted sutures were placed at the level of each crest and passed through tourniquets. In a series of three sheep, similar sutures were placed under direct vision with cardiopulmonary bypass. The supraaortic crests were augmented or maintained normal by tightening or loosening the tourniquets repeatedly. Simultaneous aortic and ventricular pressures and 2D- and M-mode echocardiography were recorded. In the dog series the results were unpredictable due to variability in the supraaortic crest enhancement because the sutures did not correspond to the anatomical crest. In the sheep series the sutures were correctly placed and M-mode echocardiography demonstrated a significant (p less than 0.01) shortening in systolic time. These results suggest the use of enhancement of the supraaortic crest as an adjunct technique in aortic valve repair.
Animals↗
The prevention of Down's syndrome in the south western region of England 1975-1985.
Cytogenetic prenatal screening for Down's syndrome in the South West Region of England from 1975 to 1985 was reviewed. The use of amniocentesis increased, and for the years 1981 to 1985 averaged 29.4% of women 35 years or over at their estimated date of delivery. 58 pregnancies were terminated after karyotyping of amniotic fluid cells confirmed trisomy 21. 385,440 live births were born in the region, 452 with Down's syndrome, giving a live birth incidence of 1 in 853. The effective impact of prenatal screening was calculated at an overall 8.3% reduction in Down's syndrome live births, but for the years 1981 to 1985 this rose to 11.3%. In spite of the introduction of new prenatal screening programmes that are not reliant solely on maternal age, it is predicted that substantial numbers of children with Down's syndrome are likely to be born each year. Adequate medical facilities will still be required for the survivors.
Adult↗
A method of practically assessing students in diagnostic radiography.
In the past, results of practical assessments were affected by their subjectivity. The objective assessment described here allows more accurate observations to be made and, while not without problems, has given favourable results.
Educational Measurement↗
Ectoparasitic and phoretic arthropods of Virginia opossums (Didelphis virginiana) in central Tennessee.
Thirteen species of ectoparasitic (12) or phoretic (1) arthropods were collected from 26 adult Virginia opossums, Didelphis virginiana, live-trapped from April through September 1987 in Davidson County, Tennessee. The cat flea Ctenocephalides felis and the American dog tick Dermacentor variabilis were the predominant species with respect to mean intensity and prevalence. The macronyssid mite Ornithonyssus wernecki and the atopomelid mite Didelphilichus serrifer, both specific parasites of this host, showed high intensities but low prevalences. Other fleas collected were Cediopsylla simplex, Ctenophthalmus pseudagyrtes, and Orchopeas howardi. The tick Amblyomma americanum, the myobiid mite Archemyobia inexpectatus, and the trombiculid (chigger) mites Eutrombicula splendens, Leptotrombidium peromysci (first record from this host) and Neotrombicula cavicola (first record from this host), were also recorded. One phoretic species, the glycyphagid mite Marsupialichus brasiliensis, was noted.
Animals↗
Anticoagulants in venous thromboembolism.
Explore the source record for details and available documents.
Administration, Cutaneous↗
Alpha-fetoprotein and acetylcholinesterase in twins discordant for neural tube defect.
Twins concordant for elevated alpha-fetoprotein (AFP) and acetylcholinesterase (AChE) and discordant for neural tube defect (NTD) and sex are reported. A literature review reveals instances of termination of twin pregnancies with one normal and one abnormal fetus, partly based on concordant high AFP and positive AChE (although discordant on ultrasound examination). The levels of AFP and AChE in twin pregnancies are probably a function of the number of layers of fetal membranes separating twin sacs; dichorionic, diamniotic membranes allow transfer of AFP; monochorionic, diamniotic membranes allow transfer of both AFP and AChE. Cautious interpretation of biochemical findings and reliance on high resolution ultrasonography are suggested.
Acetylcholinesterase↗
The influence of carotid sinus pressure on plasma atrial natriuretic peptide in anaesthetized rabbits.
The effect of changes in carotid sinus perfusion pressure on plasma immunoreactive atrial natriuretic peptide (IR-ANP) was examined in anaesthetized rabbits, and the role of arterial pressure in mediating the changes in IR-ANP was assessed. Plasma IR-ANP was significantly greater (101.7 +/- 24.3 pg ml-1) when carotid sinus pressure was 60 mmHg than when it was 160 mmHg (27.1 +/- 8.6 pg ml-1). Mean arterial pressure (MAP) was significantly greater when carotid sinus pressure was controlled at 60 mmHg compared to when it was 160 mmHg, but right atrial pressure (RAP) was not significantly different at the two carotid sinus pressures. The administration of hexamethonium attenuated the changes in MAP and heart rate (HR) which occurred in response to alterations in carotid sinus pressure, and abolished the change in plasma IR-ANP. The results suggest that an inverse relationship exists between carotid sinus pressure and plasma IR-ANP, and that the release of ANP in response to a reduction of carotid sinus pressure is mediated by the associated haemodynamic changes.
Animals↗
Limitations of Doppler ultrasound in the diagnosis of neonatal coarctation of the aorta.
Blood flow velocities were recorded using Doppler ultrasound in 40 babies aged between 1 day and 4 weeks who had coarctation of the aorta or interruption of the aortic arch. High velocity jets of 3 m/sec or more in the descending aorta were detected in only 3 patients, two of whom had interruption of the aortic arch. There was very poor agreement between upper and lower limb blood pressure difference and Doppler derived peak pressure drop. Doppler ultrasound may provide useful information on coexisting intracardiac abnormalities, but in the presence of ductal patency is of little value in the diagnosis of coarctation itself.
Aortic Coarctation↗
Continuous arteriovenous haemofiltration in the newlyborn with acute renal failure and congenital heart disease.
Newlyborn infants with congenital heart disease who develop acute renal failure are particularly difficult to treat. There are often complex associated medical problems and the mortality is high. Continuous arteriovenous haemofiltration (CAVH) provides a slow and gentle removal of fluid, together with the possibility of correcting metabolic abnormalities. We used CAVH in six newlyborn infants all with severe congenital heart disease, who developed acute renal failure early in life. In four patients it was necessary to insert a blood pump into the circuit to maintain adequate blood flow. CAVH alone, with or without a blood pump, was unable to reduce the plasma urea and creatinine, and in three of the infants, dialysis across the filter was required. CAVH was effective in controlling fluid balance. Although mortality remains high we feel CAVH has an important role in selected patients.
Acute Kidney Injury↗
A double-blind assessment of additive intolerance in children using a 12 day challenge period at home.
Alleged food-additive intolerance (respiratory, dermatological, behavioural or abdominal) was assessed in 19 children using daily challenge drinks of either, base product alone, base product plus sunset yellow/tartrazine, or base product plus sodium metabisulphite/sodium benzoate. The same type of drink was given for 12 days, double-blind and in random order. During the trial the children were maintained on an additive-free diet under supervision. Diary cards were used to record symptoms and medication usage. If there was an apparent association between symptoms and drink ingredient the trial was repeated, again double-blind. Additive intolerance was confirmed by a consistent deterioration of symptoms in only three children. In one, urticaria was induced by the colourings, in another extremely abnormal behaviour was induced by the preservatives and a third child was only free of asthma and abdominal pain on placebo. This form of individual trial, using 12 daily drinks, overcomes some of the objections to a single challenge study. Despite this, intolerance to the additives was only confirmed in 3/19 children in whom it had been believed to occur.
Adolescent↗
Plasma vasopressin and atrial natriuretic factor during haemorrhage: influence of cardiac and aortic receptors.
1. The changes in plasma concentrations of immunoreactive vasopressin (iVP) and atrial natriuretic factor (iANF) in response to haemorrhage (10-30% blood volume) were measured in 10 anaesthetized rabbits before and after cardiac receptor denervation (vagal nerve section). Carotid sinus pressure was maintained constant (60 mmHg) to eliminate any changing input from carotid baroreceptors. 2. Haemorrhage increased iVP before and after vagal nerve section indicating that withdrawal of input from aortic baroreceptors may have contributed to the increase in iVP. 3. Section of the vagus nerves attenuated the iVP response to haemorrhage. 4. There was no correlation between release of iVP and iANF. 5. Haemorrhage decreased iAF before and after vagal nerve section. Section of the vagus nerves increased iANF. Plasma iANF was highly correlated with atrial pressure and mean arterial pressure suggesting iANF release was secondary to changes in cardiac haemodynamics.
Animals↗
Plasma vasopressin and atrial natriuretic factor in response to blood volume changes in the anaesthetized rabbit.
The influence of aortic baroreceptors and vagal afferent nerves on the release of immunoreactive vasopressin (iVP) and immunoreactive atrial natriuretic factor (iANF) was examined in anaesthetized rabbits. Changes in plasma concentrations of iVP and iANF, heart rate, mean arterial pressure, and right atrial pressure were measured in response to blood volume changes (+20, +10, -10, -20%). Carotid sinus pressure was maintained at 100 mmHg (1 mmHg = 133.3 Pa), and blood volume changes were performed before and after bilateral vagotomy (VNX) in all experiments. Two experimental groups were studied: rabbits with aortic depressor nerves intact (ADNI) and those with aortic depressor nerves sectioned (ADNX). Mean arterial and right atrial pressures decreased during haemorrhage and increased in response to volume expansion. Plasma iVP concentrations increased with haemorrhage and decreased with volume expansion in the ADNI group. Plasma iANF, however, decreased with haemorrhage and increased during volume expansion in both ADNI and ADNX groups. Vagotomy caused an increase in baseline plasma iANF in the ADNX group. The responses of iANF to blood volume changes were augmented after VNX and ADNX. The results show that neither the aortic baroreceptor nor the vagal afferent input are needed for the iANF response to changes in blood volume, over the range of +/- 20%. In contrast, intact aortic baroreceptors are essential for changes in circulating iVP in this preparation.
Animals↗
Carotid sinus pressure, blood volume, and vasopressin in the anaesthetized rabbit.
Experiments were carried out on anaesthetized rabbits to determine the influence of carotid sinus pressure (CSP) on the changes in the plasma concentration of arginine vasopressin (AVP) that occurred in response to changing blood volume. The aortic depressor nerves were sectioned in all experiments and the vagus nerves remained intact. Both carotid sinuses were perfused at constant controlled pressure. Blood volume was increased (n = 10) or decreased (n = 10) by 10 and 20% of the estimated blood volume. Plasma immunoreactive arginine vasopressin concentration (IR-AVP) was significantly higher at a CSP of 60 mmHg (1 mmHg = 133.322 Pa) than it was at a CSP of 120 mmHg in both groups of animals. Increasing blood volume did not cause any significant change in IR-AVP at either carotid sinus pressure. Haemorrhage of 10% of the blood volume did not change IR-AVP. Haemorrhage of 20% of the blood volume significantly increased IR-AVP at both CSPs; the magnitude of the increase in IR-AVP was not altered by changing the CSP. No interaction was demonstrated between the effects of CSP and blood volume on plasma IR-AVP.
Anesthesia↗
Natriuretic response to hypervolemia is absent in rats with papillary necrosis.
The renal responses to acute expansion of the blood volume (20%), acute saline loading (5% body wt), or administration of atrial natriuretic peptide (ANP) were investigated in rats 7-10 days after inducing experimental renal papillary necrosis by the injection of bromoethylamine hydrobromide. In normal rats, urinary Na output (UNaV) increased from 1 +/- 0.4 to 16.6 +/- 1.7 mumol/min. In rats with papillary necrosis, UNaV only increased from 1.1 +/- 0.2 to 2.5 +/- 0.5 mumol/min. In contrast, the natriuretic responses to saline loading in normal rats (from 1.7 +/- 0.2 to 21.6 +/- 2.4 mumol/min) and to the infusion of ANP (from 0.8 +/- 0.1 to 7.6 +/- 0.8 mumol/min) were not significantly attenuated in rats with papillary necrosis. The absence of a natriuretic response to hypervolemia in rats with papillary necrosis was not a result of failure to secrete ANP, because plasma levels of immunoreactive ANP increased three- to four-fold in rats with papillary necrosis and in untreated rats. It is concluded that the mechanisms mediating the natriuretic and diuretic responses to acute expansion of the blood volume mainly involve alterations in inner medullary function. In contrast, natriuretic responses to saline loading and pharmacological doses of ANP are apparently mediated by more superficial cortical nephrons.
Animals↗
Pharmacokinetics of vasopressin and atrial natriuretic peptide in anesthetized rabbits.
The elimination from plasma of the peptide hormones vasopressin (VP) and atrial natriuretic peptide (ANP) as well as the time course of release and elimination of these hormones after a physiological stimulus were studied in anesthetized rabbits. As an inverse relationship was found to exist between carotid sinus pressure and plasma IR-ANP, a decrease in carotid sinus pressure to 60 mm Hg was used to stimulate ANP as well as VP release. The elimination of VP after iv injection involved a rapid initial phase and a slow late component, with corresponding half-life (t1/2) values of 0.9 and 5.4 min, respectively. After reduction of carotid sinus pressure to 60 mm Hg, plasma VP increased significantly within 1 min and reached a maximum at 10 min. When carotid sinus pressure was increased to 160 mm Hg to inhibit VP release, the t1/2 of VP was 1.3 min. The t1/2 of immunoreactive (IR) ANP after iv infusion was 1.2 min. Plasma IR-ANP was significantly increased 2 min after carotid sinus pressure was decreased, and a maximum was observed at 10 min. The t1/2 of IR-ANP after elevation of carotid sinus pressure to 160 mm Hg was 3.2 min. These studies indicate that both VP and IR-ANP are rapidly eliminated in the anesthetized rabbit.
Anesthesia↗
Ectoparasitic acari found on golden lion tamarins (Leontopithecus rosalia rosalia) from Brazil.
Anesthetized golden lion tamarins (Leontopithecus rosalia rosalia), a highly endangered species, were examined for ectoparasites by brushing the fur and swabbing the ears. Ectoparasites recovered from the fur included four species of immature ticks (Amblyomma spp.), three species of chiggers (Euschoengastia sp., Microtrombicula brennani and Speleocola tamarina), and one species of follicular mite (Rhyncoptes anastosi). Ectoparasites do not seem to be of particular significance to the health of the golden lion tamarin; this may in part result from grooming.
Acari↗
Doppler echocardiographic comparison of haemodynamic results of one- and two-stage anatomic correction of complete transposition.
Eighteen children who had single-stage and 18 who had two-stage anatomic correction of complete transposition between the ages of 1 week and 3 years (mean 6.5 months) were investigated with pulsed and continuous wave Doppler ultrasound. Peak mitral flow velocities showed no significant difference from normal after single-stage correction, but were significantly higher than normal after two-stage correction (P less than 0.05). Peak tricuspid flow velocities were significantly higher than normal in both groups (P less than 0.02 and P less than 0.001). There was no significant difference in pulmonary artery flow velocities between the two groups, which were means (SD) of 214 (84) cm/sec after single-stage and 179 (87) cm/sec after two-stage repair. Peak velocities in the ascending aorta were within normal limits after single-stage correction, but were lower than normal in the two-stage group (P less than 0.02). Mild aortic regurgitation was detected in 22% of single-stage and 55% of two-stage patients (P = 0.043, 2P = 0.085). Both types of repair are associated with higher peak tricuspid flow velocities than normal and have a similar incidence of mild supravalvar pulmonary stenosis. Mitral flow velocities are higher than normal only after two-stage correction. Velocities in the ascending aorta are lower than normal and the incidence of mild aortic regurgitation appears to be increased after two-stage repair, probably due to dilatation of the aortic root following banding of the pulmonary trunk.
Aorta, Thoracic↗