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Biomedical subjects

G Smith

Publications and source records attributed to G Smith.

At least 721 records · Page 40Linked to original sources
PubMed1985

The long-term outcome of nonsuppurative otitis media with effusion.

Seventy-four children were enrolled in a double-blind placebo-controlled study to define the outcome of nonsuppurative otitis media with effusion (OME) over a 12-week period. Participants were randomly assigned to one of three treatment groups: pseudoephedrine (4 mg/kg/day), chlorpheniramine (0.35 mg/kg/day), or placebo. The children were reexamined at 2, 4, 8, and 12 weeks after enrollment unless earlier dismissed from the study because OME resolved or acute suppurative otitis media developed. Of the 66 children completing the study protocol, 44 percent had resolved OME, 38 percent developed acute suppurative otitis media, 14 percent had unresolved OME, and 4 percent developed severe hearing loss or medication side effects by the end of 12 weeks. The greatest incidence of both suppurative otitis media and resolution of OME occurred by 2 weeks of follow-up. There was no significant difference in resolution of effusion between treatment groups. Children who were 18 months of age or older with unilateral effusion had the best likelihood of resolution.

Child↗
PubMed1985

Surgery for transposition of the great arteries: recent experience in the west of Scotland.

From January 1980 to May 1983, 38 children underwent corrective surgery for transposition of the great arteries using the Mustard operation at the Royal Hospital for Sick Children in Glasgow. Twenty-nine children (Group 1) had 'simple' transposition, four (Group 2) had transposition and ventricular septal defect and five (Group 3) presented with complex anomalies. Operative mortality was zero for Groups 1 and 2. In Group 3, two children died within 30 days of operation. In the follow-up period of between three months and three and a half years there have been three late deaths. This report outlines the presentation, management and short term follow-up of children who have undergone the Mustard operation in this hospital since 1980.

Cardiac Surgical Procedures↗
PubMed1985

Identification of a mouse monoclonal antibody, LHLP-1, specific for human Lp(a).

Heretofore, immunologic reagents used to define and quantify human Lp(a) have been polyclonal in origin and therefore heterogeneous in antigenic specificity. We report here the isolation of a mouse monoclonal antibody, LHLP-1, monospecific for Lp(a). The antigen reactive with LHLP-1 was expressed in both lipoprotein Lp(a) as well as apolipoprotein Lp(a) delipidated by SDS treatment; however, disulfide reduction of apolipoprotein Lp(a) inhibited LHLP-1 reactivity. The antigen reactive with LHLP-1 on Lp(a), therefore, appears not to require lipid for expression of its conformationally dependent (disulfide-inhibitable) epitope. Antigen reactivity was virtually absent in the apoB and other proteins contained in very low density, low density, and high density lipoprotein particles. Immunologic quantification of Lp(a) in individual serum samples with a rabbit reference antiserum or LHLP-1 showed good correlation. We conclude that the monoclonal antibody LHLP-1 identifies an antigen unique to Lp(a) and that this antibody may therefore be useful in the further characterization and measurement of human Lp(a).

Animals↗
PubMed1985

Post-vaccination symptoms following DTP and DT vaccination.

Post-vaccination symptoms in 6,004 infants given adsorbed Diphtheria Tetanus and Pertussis (DTP) vaccine and 4,024 infants given adsorbed Diphtheria and Tetanus (DT) vaccine have been compared. Although crying, screaming and fever were slightly more frequent after adsorbed DTP than adsorbed DT, attacks of high-pitched screaming, episodes of pallor and hypotonia, convulsions, other neurological disorders and sudden infant death occurred with similar frequency in the two groups. No specific neurological effect attributable to the pertussis component was found.

Brain Diseases↗
PubMed1985

Simulating refractive errors: source and observer methods.

There are two principal methods of simulating refractive errors. Either the retinal image can be defocused by an optical system, usually a positive lens, placed in front of an observer's eye (observer method), or the source of the retinal image can be defocused as it is projected onto a screen or photograph (source method). There are significant differences between the two methods, differences that make it difficult to compare results. However, the source method, which is the more artificial, seems to be superior for a number of reasons. The results of these two methods can be compared using a common or interchangeable parameter for specifying the level of defocus. A convenient parameter is the size of the defocused image of a point, measured either in image space (linear or angular diameter on the retina) or in object space (angular diameter of the blur disc projected back into object space), with the angular diameter measured from the respective nodal point of the eye. Methods of measuring the angular blur-disc diameter for both methods are discussed and the validity of the formula omega = D delta L, is investigated, where omega is the angular diameter of the blur disc, D is the observer's pupil diameter, and delta L is the dioptric defocus.

Humans↗
PubMed1985

Evaluation of the combined effects of atropine and domperidone on the lower oesophageal sphincter.

The effects of sequential administration of both domperidone followed by atropine, and atropine followed by domperidone were examined on the lower oesophageal sphincter of 10 healthy volunteers. Domperidone, 10 mg, increased lower oesophageal sphincter pressure (LOSP) within 10 min of injection. Atropine, 0.6 mg given at the time of peak effect of domperidone, subsequently decreased LOSP. However, frequent measurement of LOSP during the succeeding 40 min demonstrated that LOSP did not decrease significantly below control levels during this drug sequence. When the drugs were administered in the reverse sequence, atropine, 0.6 mg, decreased LOSP within 5 min of injection and subsequent administration of domperidone, at the time of peak effect of the atropine, resulted in a gradual increase in LOSP. However, control values were not approached until 30 min had elapsed after the administration of the domperidone.

Adult↗
PubMed1984

Role of heart rate in pathophysiology of chronic stable angina.

11 patients with chronic, stable, effort angina, off medication apart from glyceryl trinitrate, were monitored continuously by electrocardiogram (ECG) during normal, unrestricted daily activity. Computerised ECG analysis demonstrated during 33 twenty-four hour periods of monitoring, 278 episodes of transient ischaemic ST segment depression of which 52 were associated with angina. In the 15 minutes preceding the onset of ischaemia, heart rate did not increase in 164 episodes, increased slightly (greater than or equal to 5 beats/min) in 61, and increased moderately or markedly (greater than or equal to 10 beats/min) in 53. Findings were similar when episodes with or without angina or episodes of different severity were analysed separately. In all patients, periods of sinus tachycardia exceeding the control rate by more than 30 beats/min and lasting more than 10 minutes, often occurred in the absence of angina and/or ST segment depression. Also, in 65% of the ischaemic episodes, heart rate at the beginning of the ST change was either below or less than 10 beats/min above the modal value of the twenty-four hour heart rate. This suggests that increased myocardial demand is not necessarily the only or the most common cause of acute ischaemia in patients with chronic effort angina during unrestricted daily activity. Factors which only transiently interfere with myocardial oxygen supply are probably important in this syndrome.

Aged↗
PubMed1984

Symptoms after primary immunisation with DTP and with DT vaccine.

Symptoms after routine primary immunisation of 6004 infants with diphtheria/tetanus/pertussis (DTP) vaccine and 4024 infants with diphtheria/tetanus (DT) vaccine have been compared. After each dose, crying, screaming, and feverishness were more frequent with adsorbed DTP than adsorbed DT, but the difference was small. Attacks of high-pitched screaming, episodes of pallor or cyanosis with limpness, convulsions, and local reactions occurred with similar frequency after both vaccines. There was a considerable increase in local reactions after the 3rd dose with both vaccines. Over 1000 doses of plain DTP (with no aluminium hydroxide adjuvant) were given during the study. Post-vaccination symptoms were more common after the plain than after the 2 adsorbed preparations.

Crying↗
PubMed1984

Proteolytic activity of rabbit incisor dentine.

The presence of proteolytic activity and plasminogen activator was demonstrated in extracts of the dentine from serial sections from all regions of the incisor. Maximal activity was at neutral pH, although some was also present at acidic pH. Preparations of dentine non-collagenous matrix (NCM) proteins were sensitive to the proteolytic activity; NCM prepared by EDTA extraction contained such activity.

Animals↗
PubMed1984

Analysis of anthelmintic trial protocols using sheep experimentally or naturally infected with Fasciola hepatica.

Analytical models of the common anthelmintic trial protocols for ovine fascioliasis are used to investigate the way in which the conventional measure of anthelmintic efficiency (percentage reduction in mean fluke burden) depends on factors other than the additional fluke death rate due to chemotherapy. In prophylactic protocols where infection and dosing are coincident, the natural death rate of the parasites (both flukes and metacercariae) is an important factor. Numerical simulations indicate that the between-trial variations in anthelmintic efficiency due to fluctuations in natural parasite mortality may be substantial, especially for anthelmintic trials in the field.

Animals↗
PubMed1984

Chemotherapy of ovine fascioliasis: use of an analytical model to assess the impact of a series of discrete doses of anthelmintic on the prevalence and intensity of infection.

An analytical model of ovine fascioliasis is described. The model describes the essential features of the epidemiological patterns observed in the field and is used to assess the impact of a series of discrete doses of anthelmintic on the prevalence and intensity of infection in the flock. The reduction in prevalence after treatment with anthelmintics is shown to be critically dependent on the distribution of flukes amongst the ewes. The model is further used to define the optimum dosing times for a 2- or 3-dose regime. Model predictions concerning the optimum regime are in accord with usual treatment practices in the United Kingdom. The usefulness of analytical models of this kind in the assessment of disease control strategies is discussed.

Animals↗
PubMed1984

The impact of repeated doses of anthelmintic on the intensity of infection and age structure of Fasciola hepatica populations in sheep.

A mathematical model of ovine fascioliasis is used to assess the likely impact of repeated doses of 2 anthelmintic types on the intensity of infection in the ewes. When chemotherapy is applied in the autumn and early winter, the type of anthelmintic that kills proportionately more of the immature parasites brings about a greater reduction in the predicted overall mean intensity of infection than the type of anthelmintic that kills proportionately more of the mature parasites, and leads to a lower predicted burden of mature flukes. In both cases, each dose of flukicide has proportionately less effect on the predicted mean intensity of infection than the preceding one. It is argued that analytical models of the kind described here provide a more informative pre-trial comparison of anthelmintic properties than tabulation of age-dependent kill rates.

Age Factors↗
PubMed1984

Computer system for analysis of ST segment changes on 24 hour Holter monitor tapes: comparison with other available systems.

The accuracy of a computer system that was developed for the analysis of ST segment changes recorded on Holter ambulatory electrocardiographic monitoring tapes was compared with conventional visual scrutiny, beat by beat analog printouts and a commercial J point trend system. The program calculates and plots multiple electrocardiographically derived variables in a high temporal resolution trend format. Fifty tapes of good recording quality obtained from 19 patients (13 with chronic stable angina and 6 with variant angina) were assessed visually and with the computer system; of these, 20 were analyzed by all four techniques. In the 50 tapes, 629 episodes of diagnostic ST segment changes (all true positive results) were identified by using the computer system. In contrast, only 507 were identified by visual scrutiny; none of these 507 episodes was missed by computer analysis. On the 20 tapes assessed using computer, visual, beat by beat analog and J point trend system analysis, 268, 221, 230 and 178 episodes, respectively, were documented. For the four techniques, false negative and positive results were 0, 47, 38 and 90 and 0, 10, 6 and 24, respectively. The results indicate that, of the systems assessed in this study, the computer program provides the highest accuracy for detection of transient ST segment changes. This is probably accreditable to the compact presentation of multiple electrocardiographically derived variables, allowing a detailed quantitative assessment of 24 hour tapes. It is of particular value for pathophysiologic and pharmacologic studies.

Angina Pectoris↗
PubMed1984

The relationship between the size of Lymnaea truncatula naturally infected with Fasciola hepatica and the intensity and maturity of the redial infection.

Of the 2,652 Lymnaea truncatula collected from sites in Cumbria and Gwynedd during 1973-75, when the prevalence of fascioliasis in the primary host was low and declining, only 123 were infected with Fasciola hepatica. Dissection of these snails revealed that the proportion infected, the mean redial burden and the proportion of mature rediae in each snail increased with shell length. The results are compared with a similar data set acquired when the prevalence of infection in both the primary and intermediate hosts was uncharacteristically high. Although the results are qualitatively similar, there are important quantitative differences. The mean redial burden of infected snails at times of high disease prevalence was generally twice as high as that reported in the present study. It is suggested that differences in habitat microclimate could not account entirely for the observed differences in redial burden and the role of multiple miracidial infection is discussed.

Animals↗
PubMed1984

The influence of water temperature and pH on the survival of Fasciola hepatica miracidia.

Experimental studies on the survival of Fasciola hepatica miracidia show no evidence that miracidial mortality varies with the pH of the medium, at least in the range 6.0-8.0. On the other hand, miracidial mortality is shown to vary with both the temperature of the medium and the age of the larvae. The mean expected life-span of the miracidium decreases from about 35 h at 6 degrees C to about 6 h at 25 degrees C. The Gompertz survival function provides a good description of the miracidial survivorship curves over the range of temperatures used, and we describe a maximum likelihood method of estimating the mean values of the parameters of this function, together with their approximate 95% confidence limits.

Animals↗