Biomedical subjects

G Smith

Publications and source records attributed to G Smith.

At least 685 records · Page 38Linked to original sources

PubMed1986

Changes in plasma catecholamine concentrations following infiltration with large volumes of local anaesthetic solution containing adrenaline.

Plasma catecholamine concentrations have been measured in nine patients undergoing rhinoplasty following infiltration to the facial area of 21 ml of 0.5% lignocaine with adrenaline 1:200,000 and in seven patients undergoing brachial plexus blockade with 40 ml of 0.5% lignocaine, 0.25% bupivacaine and adrenaline 1:200,000. In the rhinoplasty group there was a 566% increase in plasma adrenaline concentration 2 min after cessation of infiltration, whilst in the brachial plexus group a 112% increase in the plasma concentration of adrenaline occurred at 10 min after completion of the block. There was no change in plasma noradrenaline concentration in either group. It is concluded that the so-called safe dose of adrenaline (1.0 microgram kg-1 during halothane anaesthesia) is meaningless unless the site of administration is specified.

Anesthesia, Local↗

PubMed1986

Absorption of controlled release morphine sulphate in the immediate postoperative period.

The absorption of morphine sulphate, given orally as a controlled release preparation, was studied in 10 patients who had undergone peripheral vascular surgery with a standard opioid-based general anaesthetic technique. Serum morphine concentrations were measured (high pressure liquid chromatography) every 2 h for the first 16 h after surgery and the results were strongly suggestive of a decrease in the rate of absorption of morphine in this situation.

Administration, Oral↗

PubMed1986

On the description of zonal aspheric surfaces.

It is shown that, in general for a rotationally symmetric surface, the sagittal curvature is a function of the first derivative and tangential curvature is a function of the first and second derivatives of the surface equation. Smith and Atchison developed an "off-set" model for zonal aspheric surfaces with continuous gradients (or first derivatives) at the boundaries between zones of the surface, and discontinuous second derivatives at the boundaries. This model predicts continuous sagittal power errors but discontinuities in tangential power errors. However, measurements on commercially available zonal lenses by Atchison and Smith showed that both sagittal and tangential power errors were continuous across zone boundaries. Thus it is likely that the off-set model is incorrect. Zonal aspheric surfaces are more likely to be made according to a "co-axial" model which is described.

Humans↗

PubMed1986

Schematic eye predictions of relative spectacle magnification in unilateral aphakia.

Computer ray tracing provides a simple technique for investigating binocular relative spectacle magnification (BRSM) in the patient with unilateral aphakia. BRSM is defined as the retinal image size in the corrected aphakic eye relative to the retinal image size in the corrected phakic eye. The influence of preoperative ametropia and the mode of correction on BRSM is investigated, using Gullstrand's number 2 schematic eye as a model.

Aphakia↗

PubMed1986

Anxiety levels in junior anaesthetists during early training.

Trait anxiety levels (predisposition to anxiety) and personality profiles were recorded in four novice anaesthetists prior to the start of their training in anaesthesia. State anxiety (the extent of anxiety at the moment of testing) was also assessed before and after the transition from accompanied to solo anaesthetic practice. There was no demonstrable difference in anxiety scores as a result of 'going solo' in any subject.

Adult↗

PubMed1986

Superficial bladder cancer: intravesical chemotherapy and tumour progression to muscle invasion or metastases.

Of 299 patients who presented with superficial bladder cancer (Ta, T1), 60 were treated by intravesical chemotherapy (Epodyl, methotrexate or mitomycin C). The rate of tumour progression to muscle invasion or metastases was identical for each intravesical regime. There was no evidence that mitomycin C promoted tumour progression. Carcinoma in situ in non-tumour-bearing urothelium was the most significant predictive factor for progression to muscle invasion or metastases.

Administration, Intravesical↗

PubMed1986

Echocardiographic measurement of the normal adult right ventricle.

In studies of the right ventricle the complexities of chamber shape may be overcome by use of multiple tomographic imaging planes. An established protocol for the echocardiographic description of the heart was used to examine the right ventricle in an ordered series of transducer locations and orientations. Diastolic measurements were made of the right ventricular inflow tract, outflow tract, and right ventricular body, and the range and reproducibility of normal values for cavity size and right ventricular free wall thickness were established. These measurements of cavity size in 41 normal subjects were highly reproducible and the views that were used correctly described the truncated and ellipsoidal shape of the right ventricular inflow tract and body with a separately aligned outflow tract. Cavity trabeculation prevented measurement of the free wall thickness in some areas; however, values of nearly twice the previously reported upper limit of normal for anterior regions were measured from the apex or lateral right ventricular wall. These normal data provide a basis for future echocardiographic studies of the right ventricle.

Adult↗

PubMed1986

Angiotensin-stimulated drinking in marine fish.

Drinking rates in both marine and freshwater stenohaline fish were studied by measuring the ingestion of polyethylene glycol that had been added to the aquarium water. Two marine species, the long-horned sculpin and the flounder, and three freshwater species, the common goldfish, the mottled sculpin, and the common shiner, were used. Control drinking rates in freshwater fish averaged 0.03-0.1% body wt/h and in marine fish varied between 0.06 and 0.24% body wt/h. Intramuscular injections of angiotensin II (ANG II) stimulated drinking two- to threefold in the two marine species but had no effect on the drinking rate of the freshwater species. Hemorrhage (1-2% of body wt) also stimulated drinking in the two marine species (6- to 10-fold) but did not affect the drinking rate of two freshwater species. Thus exogenous ANG II and hemorrhage stimulate drinking in two marine stenohaline fish as they do in mammals. These responses were absent in the three freshwater fishes studied. However, injection of converting enzyme inhibitor (SQ 20881) or saralasin in order to block endogenous ANG II did not attenuate either basal or hemorrhage-stimulated drinking in the marine fish.

Angiotensin II↗

PubMed1986

Late presentation of ventricular septal defect following myocardial infarction: the role of non-invasive methods.

A 64-year-old man presented with biventricular failure 5 months after an acute antero-apical myocardial infarction. On auscultation of the praecordium a loud pansystolic murmur was heard. The use of non-invasive studies in diagnosing post-myocardial infarction ventricular septal defect is discussed.

Echocardiography↗

PubMed1986

Effect of a blood transfusion protocol and low dose steroid regime on renal transplant survival.

The effects of introduction of a low steroid regime and pre-transplant blood transfusion were evaluated. The kidney and patient survival rates for the period before such a policy was adopted were compared with the period after this policy. There has been a highly significant rise in patient survival rates to the present level of 95 per cent at three years. There was a similar rise in three year graft survival rates from less than 40 per cent to 66 per cent.

Actuarial Analysis↗

PubMed1986

A comparative study of diazepam with sustained-release diazepam as oral premedication in minor gynaecological surgery.

Sixty patients undergoing elective minor gynaecological surgery received oral pre-operative medication with 10 mg diazepam in either conventional tablet form on the morning of operation or as the sustained-release tablet the night before. Subjective and objective assessments of the effectiveness of premedication were made. Patients receiving sustained-release diazepam on the night before surgery experienced fewer periods of wakefulness than those who received placebo. Patients who were given diazepam on the morning of surgery felt more drowsy pre-operatively than those who received sustained-release diazepam the night before.

Adolescent↗

PubMed1986