Biomedical subjects

D A Yates

Publications and source records attributed to D A Yates.

At least 19 recordsLinked to original sources

PubMed2001

The ability of plain radiography to predict intracranial aneurysm occlusion instability during follow-up of endosaccular treatment with Gugliemi detachable coils.

Incomplete occlusion of an intracranial aneurysm at follow-up after treatment with Gugliemi detachable coils (GDC) increases the risk of rebleeding and serial angiographic monitoring is therefore currently indicated. We aimed to determine if a change in the plain radiographic appearances of the GDC ball could accurately predict the presence of unstable angiographic occlusion. Paired GDC radiographs (in two planes) and cerebral angiograms, performed immediately after treatment and at follow-up or at two consecutive follow-up examinations, were retrospectively compared. Radiographs were assessed for the radiographic change (loosening, compaction or reorientation) in the coil-ball and angiograms for unstable aneurysm occlusion (neck recurrence or deteriorating occlusion). We compared 49 paired films from 38 patients. Radiographic change in the coil ball had a negative predictive value of 96%, positive predictive value of 57% and accuracy of 76% for the presence of angiographic aneurysm instability. It may be possible to increase the interval between follow-up angiographic examinations after GDC treatment safely if there is no change in the radiographic appearances in two planes.

Adult↗

PubMed2001

Adaptation of stress-induced mucosal pathophysiology in rat colon involves opioid pathways.

Acute stress increases ion secretion and permeability of rat colonic epithelium. However, it is not known if stress-induced mucosal changes are subject to adaptation. Wistar-Kyoto rats were exposed to either continuous water-avoidance stress (CS) for 60 min or intermittent stress (IS) for three 20-min periods. Distal colonic segments were mounted in Ussing Chambers, and ion-transport [short-circuit current (I(sc))] and permeability [conductance and flux of horseradish peroxidase (HRP)] parameters were measured. CS significantly increased I(sc), conductance, and HRP flux compared with control values. In contrast, in IS rats these variables were similar to those in nonstressed controls. To study the pathways involved in IS-induced adaptation, rats were pretreated intraperitoneally with the opioid antagonists naloxone or methylnaloxone. Opioid antagonists had no effect on values in control or CS rats. However, in the IS group, naloxone and methylnaloxone reversed the adaptive responses, and all variables increased to CS values. We conclude that stress-induced colonic mucosal pathophysiology is subject to rapid adaptation, which involves opioid pathways.

Adaptation, Physiological↗

PubMed1995

Efficacy of laidlomycin propionate to reduce ruminal acidosis in cattle.

Three trials were conducted to evaluate the efficacy of laidlomycin propionate (LP) to reduce the incidence and severity of ruminal acidosis in cattle fed high-grain finishing diets. In each trial, LP was fed at 0, 6, or 12 mg/kg of diet DM. In two acidosis-challenge trials, ruminally fistulated steers were fed (DM basis) a 50% concentrate diet and then fed a 95% concentrate diet at a specific intake (2.75% BW) or steers were dosed intraruminally with a 100% concentrate diet. Laidlomycin propionate did not alter ruminal pH or total acid concentrations, but in Trial 1 the 6 mg/kg level altered (P < .10) the molar proportions of the acids, increasing total ruminal VFA and decreasing ruminal lactate. In Trial 3, a finishing trial, LP reduced (P < .10) intake day-to-day variation of individually fed steers during a 13-d adaptation period from a 65 to a 100% concentrate diet, suggesting reduced incidence of subacute acidosis. Feed intake was lower (P < .05) during the first 13 d of the trial due to LP but was not affected over the entire trial. Laidlomycin propionate improved feed efficiency (gain/feed) when calculated on a live weight basis (linear, P = .05) or carcass weight basis (linear, P = .20). Laidlomycin propionate does not prevent ruminal acidosis, but it may reduce the severity of ruminal acidosis during adaptation to a 100% concentrate diet.

Acidosis↗

PubMed1992

Stereotactic linac radiosurgery for arteriovenous malformations.

Stereotactic linear accelerator (linac) radiosurgery has been in operation in the West Midlands since 1987, the first of its kind in the United Kingdom. Forty two patients with high-flow cerebral arteriovenous malformations have been treated, 26 of whom have been followed up. Angiography one year after treatment showed that five lesions were obliterated, 11 were reduced in size and/or flow rate and 10 were unchanged. Overall results show that nine out of 10 patients reviewed at 24 months had total obliteration. Three patients had complications; one has fully recovered, one died of an unrelated cause at 36 months and the other died from recurrent haemorrhage at nine months. Two patients had recurrent non-fatal haemorrhage within 24 months of treatment; both recovered without further deficit. All patients are fit to work but eight are unemployed. Although the follow up period is short, the early results indicate a success rate similar to those published by others using linac radiosurgery.

Adolescent↗

PubMed1987

Adherence of rheumatoid polymorphonuclear cells (PMNs) to cultured endothelial cell monolayers.

Blood polymorphonuclear cells (PMNs) from 40 patients with rheumatoid arthritis (RA) and 40 normal subjects were incubated with confluent cultures of porcine aortic endothelium and their adherence assessed by either a microscopic or radiometric enumeration assay. There was no difference between the number of rheumatoid and control PMNs adhering. The synovial fluid PMNs from patients with RA were less adherent than their paired blood samples when autologous serum was present in the incubation medium and more adherent when serum was absent. Most of the RA sera tested inhibited the adhesion of normal PMNs, an effect that was not due to an increase in PMN aggregation. A similar inhibition was seen with sera obtained from patients with Felty's syndrome. These findings suggest that there is no intrinsic difference between the adhesiveness of rheumatoid PMNs and normal PMNs but that there are soluble factors present in RA serum which inhibit the attachment of normal PMNs to vascular endothelium.

Arthritis, Rheumatoid↗

PubMed1986

Aggressive polyfibromatosis.

Explore the source record for details and available documents.

Fibroma↗

PubMed1982

A comparative trial of sodium meglumine ioxaglate (Hexabrix) and iopamidol (Niopam) for cerebral angiography.

We have carried out a randomized blind trial comparing iopamidol (Niopam) and sodium meglumine ioxaglate (Hexabrix) in cerebral angiography in 50 patients. There was no significant difference in the degree of pain or movement produced by the contrast media. The degree of heat felt was slightly greater with iopamidol than with ioxaglate. Both were very well tolerated by patients, producing only a mild or moderate sensation of heat, and in only a few instances slight pain during the injections. No difference in radiographic quality was observed. We conclude that both media are a significant advance over the conventional ionic media and the choice between them will be determined by factors of neurotoxicity, ease of use and cost.

Carotid Arteries↗

PubMed1981