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Biomedical subjects

J Lindsay

Publications and source records attributed to J Lindsay.

At least 145 records · Page 8Linked to original sources
PubMed1985

Radioisotope techniques in the evaluation of patients with coronary artery disease.

Cardiac scintigraphy provides an exciting new diagnostic modality. Currently, its two major clinical applications are the identification of patients with ischemic heart disease and the characterization of ventricular function. These techniques also appear to have utility in assessing the size of myocardial infarction, the severity of obstructive coronary disease, and the effects of medical or surgical therapy. Continued careful correlation of clinical and scintigraphic findings will make these techniques even more useful in the future.

Coronary Circulation↗
PubMed1984

Relation of ST-segment elevation after healing of acute myocardial infarction to the presence of left ventricular aneurysm.

Persistent ST elevation after healing of myocardial infarction (MI) is often cited as an electrocardiographic sign of left ventricular (LV) aneurysm. This sign is rare in patients with coronary artery disease who have normal or only mildly deranged LV function and is most often associated with QRS patterns indicative of large MI, especially anterior wall MI. To determine whether ST elevation identifies a distinctive abnormality of LV function that might be labeled LV aneurysm, global and regional LV function in 12 patients with QRS patterns of anterior MI and ST elevation were compared with that in 12 patients with similar QRS abnormalities but without ST elevation by means of radionuclide ventriculography. All measured parameters of ventricular function were similar in the 2 groups. ST elevation could not be demonstrated to predict a distinctive abnormality that might be labeled LV aneurysm.

Adult↗
PubMed1984

Effect of intravenous dipyridamole on regional coronary blood flow with 1-vessel coronary artery disease: evidence against coronary steal.

The effects of i.v. dipyridamole were studied in 9 patients with isolated total left anterior descending coronary artery (LAD) obstruction, in 6 patients with isolated 90 to 99% diameter reduction of the LAD and in 10 patients with normal coronary arteries and normal left ventricular function. Coronary sinus and great cardiac vein flows were determined by continuous thermodilution. Flows were measured at rest and 1, 3, 5 and 10 minutes after i.v. dipyridamole. Great cardiac vein flow represents the venous outflow from the LAD territory. In the presence of coronary steal from the LAD territory, great cardiac vein flow is expected to decrease while coronary sinus flow increases. Intravenous dipyridamole induced a similar flow increase in the coronary sinus and the great cardiac vein in all 3 groups (p less than 0.001 between rest and dipyridamole, difference not significant among groups), suggesting that no coronary steal was induced. The maximal increase in great cardiac vein flow was 118 +/- 74% in the control group, 86 +/- 74% in the group with 90 to 99% LAD obstruction and 102 +/- 29% in the group with total LAD obstruction (difference not significant). These data show that i.v. dipyridamole produces a similar increase in coronary flow in ischemic and nonischemic areas and suggests that an increase in collateral flow is the underlying mechanism for increased flow to the ischemic area.

Adult↗
PubMed1984

Long-term outcome in children with temporal lobe seizures. V: Indications and contra-indications for neurosurgery.

One hundred unselected children with temporal lobe epilepsy were followed up between 1948 and 1982. The series was a personal one. None was lost to observation. For 42 patients, contra-indications for surgery had emerged before the end of their schooldays. 29 cases were considered for surgery. 16 were rejected on technical grounds, and none of these made an epileptic, social, psychiatric or personality recovery. 13 patients were operated on, none of whom continued to have habitual epilepsy: all their biographies were remarkably improved, though several years postoperative care sometimes was needed. The authors conclude that surgery plays a major rôle in the treatment of temporal lobe epilepsy of childhood, and those who would benefit usually can be recognised before leaving school.

Adolescent↗
PubMed1984

Developmental aspects of focal epilepsies of childhood treated by neurosurgery.

Data on 50 patients treated surgically for intractable focal epilepsy were analysed. There were 10 hemispherectomies, 32 temporal lobectomies and eight operations to other areas of the brain. The median age at operation was 14 years. 29 patients were found to have mesial temporal sclerosis or sclerotic hemispheres and 17 had alien tissue and one sclerosis with heterotopia. No lesion was found in three cases. The nature of the first seizure was found to relate significantly to pathology. 30 patients had suffered an early convulsion. Between the convulsive insult and the onset of focal epilepsy there was a silent interval, the duration of which was biased by sex and side of lesion. The remaining 20 patients, of whom a highly significant number had alien tissue, had not had an early convulsion before the onset of focal epilepsy. The importance of accurate clinical histories is stressed. Clinical considerations alone predicted the pathology and laterality of the lesion in more than half the series. Regular EEG recordings and repeat scanning were found to be important investigations. Major disorders of behaviour had occurred in 44 patients. As adults, the series were free of severe psychiatric symptoms, but many required years of careful rehabilitation. 31 children had been excluded from normal schools before operation. Postoperatively, many patients continued their education in normal schools. Some required basic remedial teaching, others successfully undertook higher education and training. 49 patients benefited over-all from neurosurgical treatment. 34 had no more habitual epilepsy at all. Full global gains often took at least five years to achieve.

Adolescent↗
PubMed1983

Effects of beta-adrenergic blocking drugs on sensitivity and specificity of radionuclide ventriculography during exercise in patients with coronary heart disease.

We examined the impact of beta-adrenergic blocking drugs on the sensitivity and specificity of radionuclide ventriculography in 95 patients with angiographically proved coronary disease and in 22 angiographically normal subjects. Sixty of the former and seven of the latter were receiving beta-adrenergic blocking agents. All had normal regional and global left ventricular function at rest. Exercise-induced asynergy and failure of exercise to increase ejection fraction by at least 0.05 were considered abnormal findings. The specificity of the criterion, failure to increase ejection fraction, was so impaired (0.87 vs 0.29) by these agents as to negate the usefulness of that observation for the diagnosis of coronary disease. The utility of the ejection fraction measurement to assess the severity of occlusive disease is also compromised, since that response is ameliorated by these drugs. An exercise-induced decline in ejection fraction of at least 0.05 was observed significantly less frequently in patients receiving beta blockers (30% vs 54%; p less than 0.025).

Adrenergic beta-Antagonists↗
PubMed1983

The electrocardiogram as an index of left ventricular function in coronary heart disease.

To determine the utility of conventional electrocardiographic criteria for the assessment of left ventricular function, we applied pre-determined criteria to the analysis of the ECGs of 171 patients with chronic coronary disease. Eighty patients had no criteria for infarction. Seventeen had a criterion for anterior, 59 a criterion for inferior, three for strict lateral, four for true posterior and eight for combined infarction. Of the 59 with inferior infarction, 25 had QaVF greater than or equal to 0.03 sec. These 25 together with the 25 with anterior or combined infarction constituted a subgroup of 50 patients which included 35 of the 44 (80 percent) of those with an ejection fraction less than 0.50. Among the remaining 121, only nine (7 percent) had a depressed ejection fraction. Thus, the ECG criteria identified correctly 147 (86 percent) patients with regard to the presence or absence of left ventricular dysfunction.

Aged↗
PubMed1983

Differentiation-arrested rat fetal lung in primary monolayer cell culture. I. Development of a differentiation-arrested and growth-supporting culture system using carbon-stripped bovine fetal calf serum.

In vitro observations of fetal lung maturation are complicated by continued epithelial cell maturation in culture. Removal of trace quantities of cortisol from the culture system has been reported elsewhere by Torday to prevent epithelial cell differentiation, but also prevent cell growth. In this report we have developed monolayer cell cultures from 18-, 19-, 20-, and 22-day-gestation fetal rat lung in a culture system stripped of steroid and thyroid hormones. These cultures demonstrate lamellar body development comparable to that seen in vivo at the gestational age at which cultures were developed; the gestation-dependent increase in precursor incorporation into saturated lecithin observed in these cultures is similar to that reported in in vivo studies, yet cell growth in culture has been preserved.

Animals↗
PubMed1983

Differentiation-arrested rat fetal lung in primary monolayer cell culture. II. Dexamethasone, triiodothyronine, and insulin effects on different gestational age cultures.

Differentiation-arrested and hormone-depleted monolayer cultures were developed from rat fetal lungs of 18-, 19-, 20-, and 22-days gestation. Incorporation of [3H]-choline into saturated phosphatidylcholine increased, whereas the rate of cell division decreased, with advancing gestational age. Both functions were modified by physiological concentrations of glucocorticoids, thyroid hormones, and insulin. Dexamethasone (0.055-5.5 nM) increased [3H]-choline incorporation into total saturated phosphatidylcholine in immature cultures only, but caused secretion in mature (day-22) cultures. Triiodothyronine (0.055-5.5 nM) increased [3H]-choline incorporation into total and secreted saturated phosphatidylcholine at all gestational ages. Insulin (5-50 microU/ml) inhibition of [3H]-choline incorporation into saturated phosphatidylcholine was evident only in mature cultures. Dexamethasone (0.55 nM), triiodothyronine (5.5 nM), and insulin (50 microU/ml) also had gestation-dependent effects on cell division.

Animals↗
PubMed1983

Cancer mortality (1965-77) in relation to diesel fume and coal exposure in a cohort of retired railway workers.

A cohort study of 43,826 male pensioners of the Canadian National Railway Company was conducted. The cause of death of 17,838 pensioners who died between 1965 and 1977 was ascertained by computerized record linkage to the Canadian national mortality data base. The main finding was an elevated risk of lung cancer for those employed in occupations involving exposure to diesel fumes and coal dust, with highly significant dose-response relationships observed. That such association may be due in part to smoking cannot be excluded; but in view of the widespread exposure to diesel fumes, the finding warrants further investigation. The present study also demonstrated the utility and feasibility of large-scale occupational cohort studies conducted with the use of computerized record linkage to national mortality records.

Aged↗
PubMed1982

Radionuclide ventriculography following coronary bypass surgery: correlation with arteriographic findings.

Radionuclide ventriculography demonstrates improved left ventricular performance during exercise following coronary bypass operation, but few data are available that compare the nuclear ventriculographic findings with arteriographic evaluation. We report the findings in 25 patients in whom both tests were performed within a short period of time. coronary bypass operations had been performed six weeks to nine years previously. Ejection fraction (EF) increased during stress in 5 completely revascularized patients. Exercise provoked deterioration in regional wall motion in 9 of 20 (45%) patients with incomplete revascularization, and EF failed to rise during exercise in 15 (75%). Although resting EF was similar in both completely revascularized patients and in those who were not (0.06 versus 0.58), EF during exercise was significantly greater in completely revascularized patients (0.68 +/- 0.02 versus 0.55 +/- 0.03, p less than 0.01). Exercise-provoked decline in EF in patients with coronary artery bypass grafts reflects continued significant occlusive disease.

Adolescent↗
PubMed1982

Ticarcillin associated hypokalemia.

We evaluated the presence and degree of hypokalemia associated with ticarcillin disodium (ticarcillin) therapy in 16 patients. Four of these patients who received less than 10 grams of ticarcillin did not develop significant hypokalemia, but this condition developed in 6 of 9 patients receiving a daily dose of greater than 18 grams of this drug, and the mean urinary potassium was elevated in this group (mean = 78 mEq/24 hrs). The degree of hypokalemia was correlated with the volume status of the patient as judged by the serum urea nitrogen: creatinine ratio. A positive correlation (r = 0.66, p less than 0.05) was obtained between the two parameters. Hypokalemia did not develop in three patients with the syndrome of inappropriate secretion of anti-diuretic hormone who were receiving more than 18 grams of ticarcillin daily, indicating the absence of a stimulus for sodium conservation. Aggressive potassium and fluid replacement should be considered in patients with hypokalemia associated with ticarcillin therapy.

Adolescent↗
PubMed1982

Developing a forensic dental code and programme.

An attempt was made to develop a computer-assisted programme to aid in the positive identification of human remains. The first and second generations of a computer code and programme for entering ante-mortem and post-mortem records into a computer data bank are discussed. The initial code is presented along with the results following the computer evaluation of 50 record pairs. The self-evaluating aspects of the programme are discussed and the proposed second generation code is presented. The programme exhibits some promising characteristics but further refinement based on increased data banks is needed.

Computers↗