Biomedical subjects
Publications and source records attributed to J Reid.
A report of an aesthetic and simple restorative solution to a difficult problem of orthodontic retention. The case described involved the use of etch retained porcelain restorations and includes a porcelain cantilever laminate bridge.
The protein pattern of cerebrospinal fluid (CSF) of 334 patients with various neurological and systemic diseases was investigated by high resolution two-dimensional electrophoresis (2-DE). 2-DE gels of normal CSF contain proteins which are not detectable in 2-DE gels of serum. Disturbances of the blood-brain or blood-CSF barrier, and degenerative diseases of the brain and malignant diseases produce specific changes on 2-DE gels of the CSF. The appearance of 10 spot areas in the light chain region of 2-DE gels seem to be connected with the diagnosis of multiple sclerosis. The sensitivity and the specificity of these spot areas for the diagnosis of multiple sclerosis are described. Proteins within the ten spot areas are immunoglobulin light chains or substances which cross-react very strongly with light chain antibodies as demonstrated by immunoblotting and immunoabsorption.
Thirty-three patients with renal angiographic evidence of significant renal artery stenosis were referred for percutaneous transluminal angioplasty. The indications were poorly controlled hypertension (n = 13) or hypertension associated with deteriorating renal function (n = 20). Their mean age was 56 (23-73) years (12 males, 21 females). Causes of the renal artery stenosis were fibromuscular dysplasia (n = 8) and atheromatous changes (n = 25). Four patients were excluded, three due to technical failure. Forty-five angioplasties were performed in 29 patients with a mean observation period after angioplasty of 18 (one to 60) months. During this period eight patients (28 per cent) had a diastolic blood pressure of less than 90 mmHg without antihypertensive drugs, a further 15 patients (52 per cent) had improved blood pressure control with a significant reduction in the number and amount of antihypertensive drugs, but six patients (20 per cent) showed no improvement in blood pressure. Hypertension associated with the stenosis of fibromuscular dysplasia responded better to angioplasty than hypertension associated with atheromatous renal artery stenosis. Improvement in renal function was noted in eight patients with no change in 16 patients. Two patients with end-stage renal failure and atheromatous intrarenal vascular disease became dialysis dependent within four weeks of the procedure. One major and four minor complications occurred but there were no deaths related to angioplasty. Together with results from other centres this study indicates that percutaneous transluminal angioplasty should be considered the initial treatment choice for all patients with renovascular hypertension due to fibromuscular dysplasia and atheromatous renal artery stenosis.
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We have examined the influence of endothelial cell removal upon the O-methylation of the isomers of isoproterenol in the isolated rabbit aorta. Endothelial cells were removed by mechanically abrading isolated segments of rabbit aorta. The latter procedure resulted in the abolition of acetylcholine-mediated relaxation of tissues, a process dependent upon the presence of endothelial cells. In addition, histological staining and electron-microscopic analysis indicated the presence of endothelial cells in tissues not subjected to mechanical abrasion and the absence of endothelial cells in tissues subjected to abrasion. Moreover, ultrastructural analysis revealed that the influence of abrasion was limited to the luminal side of the internal elastic lamina. The removal of endothelial cells from the isolated rabbit aorta was associated with a decrease (approximately 30%) in the O-methylation of the isomers of isoproterenol. Inhibition of the extraneuronal uptake process with deoxycorticosterone (DOCA) produced a predicted decrease in the O-methylation of isoproterenol in tissues with the endothelium intact. In the absence of endothelial cells, the inhibition of the O-methylation of isoproterenol mediated by DOCA persisted. The results suggest that the O-methylation of catecholamines can occur in both medial and endothelial structures in this blood vessel and support the results of immunohistochemical studies that suggested a presence of catechol-O-methyltransferase in vascular endothelial structures. In addition, the findings exclude a possibility that the extraneuronal uptake process for catecholamines resides exclusively in endothelial structures. The functional consequences of vascular endothelial cell O-methylation are discussed.
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The authors wished to test the hypothesis that atrioventricular synchrony has a relatively greater effect on hemodynamic parameters in postoperative patients with low ejection fractions compared to those with normal ejection fractions. Temporary pacing wires were placed on the right atrium and right ventricle of patients undergoing open heart surgery. Duplicate thermodilution cardiac outputs were determined during atrial pacing and ventricular pacing at 100 beats/min. Mean left atrial and systemic blood pressures were monitored. Thirteen patients with ejection fractions of 45 per cent or less (range 24 to 45%, mean 37.3%) were included in the low ejection fraction group, and 27 patients with ejection fractions of 59 per cent or greater (range 59 to 80%, mean 66.8%) were considered in the normal ejection fraction group. All hemodynamic parameters improved significantly when changing from ventricular pacing to atrial pacing in both the normal ejection fraction group and low ejection fraction group (P less than 0.05). The magnitude of change between the groups showed no significant difference for all parameters except left atrial pressure, which decreased by a greater percentage in the low ejection fraction group with atrial pacing (P less than 0.001). The atrial contribution to hemodynamic enhancement is important in patients with normal and low ejection fraction following open heart surgery. Patients with low ejection fractions do not sustain a relatively greater reduction in cardiac output, stroke volume index, or systemic blood pressure with loss of atrioventricular synchrony when compared to patients with normal ejection fractions.
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The effect of thyroid status on the postnatal development of the two molecular forms of Na+,K+-ATPase, distinguished kinetically on the basis of their ouabain sensitivity, was examined in rat brain. Hypothyroidism induced by PTU from day 1 postnatally significantly reduced the Na+,K+-ATPase activity in cerebellum (22-30 days) but not forebrain, whereas hyperthyroidism (T4 treatment from day 1) had no effect. The hypothyroidism-induced reduction in cerebellum was reflected by a 20-45% reduction in the activity of the alpha(+) form of Na+,K+-ATPase (high ouabain affinity) against control brains compared to a 60-70% reduction in the activity of the alpha form (low ouabain affinity). These results show that neonatally induced hypothyroidism leads to a selectively greater impairment of the ontogenesis of the activity of cerebellar alpha form of Na+,K+-ATPase. This may possibly reflect a retarded development of a selective cerebellar cell population containing predominantly the alpha form of the enzyme.
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Three types of carotid sinus (CS) syndrome have been described: cardioinhibitory, vasodepressor and mixed. For the treatment of symptomatic patients with associated significant cardioinhibition, permanent ventricular demand pacing systems are often implanted. Even with this pacing modality, some patients remain symptomatic because of continued (and at times aggravated) vasodepression. This study assesses the effects of loss of atrial preloading and orthostasis after carotid massage in patients with CS hypersensitivity. Eleven patients were studied using constant intra-arterial pressure measurements during either ventricular (VVI) or atrioventricular sequential (DVI) pacing in both supine or upright positions. The measurements performed included the magnitude of decrease in arterial blood pressure (BP), the rate of decrease of BP and the percent change in BP from baseline values. After carotid massage, all 11 patients had greater hemodynamic change with the VVI than DVI pacing mode, whether in the supine or upright position. The decreases in systolic BP were: DVI (supine) 29 mm Hg, VVI (supine) 48 mm Hg, DVI (upright) 37 mm Hg, and VVI (upright) 59 mm Hg (mean group values, p less than 0.001). The rates of decrease of systolic BP were: DVI (supine) 2.9 mm Hg/s, VVI (supine) 5.7 mm Hg/s, DVI (upright) 4.1 mm Hg/s, and VVI (upright) 8.3 mm Hg/s (mean group values, p less than 0.001). VVI pacing, particularly in the upright position, resulted in a significant increase in the incidence of patient symptoms (p = 0.03). Thus, in CS hypersensitivity, VVI pacing results in significant hemodynamic deterioration compared to DVI mode. This aggravation of the vasodepressor component results in increased patient symptoms, and therefore, DVI is the optimal pacing mode.
This paper describes a behavioural study of the infant nutrition and family planning education components of selected maternal and child health clinics in Madang Province in Papua New Guinea. Staff of six (6) clinic teams were observed during 18 rural and urban clinics and the content and length of the nurses' interactions with the 254 mothers of 340 children recorded. Three-quarters (71%) of the interactions took less than 2 minutes. Family planning advice was rarely given. The amount of time the nurse spent with mother and child primarily depended on whether the child was sick or well, rather than on his/her nutritional status. Nutritional advice, when offered (to mothers of 27% of children below 80% WFA), was given in response to WFA alone, independently of health status, age and rate of growth. It is suggested that the low priority given to nutrition and family planning education is the result of inadequate supervision, complex reporting systems, the routine nature of the work, preference of nurses for structured clinical tasks and nurses' attitudes to clients and contraception. Clinics would be more effective if oriented around problems rather than tasks, and families rather than individuals. This would also give nurses the satisfaction of seeing the goals and results of their work. It is suggested that the MCH system would benefit from innovative pilot programmes which address the special problems of remote areas and derive from primary health care principles.
Peripheral blood lymphocytes (PBL) from 38 normal donors and from 27 cancer patients were propagated in bulk cultures for 3-6 weeks using T cell growth factor (TCGF). In addition, cultures derived from lymphocyte preparations enriched for or depleted of natural killer (NK) cells and several clones of cultured cells were studied. The following main observations were made: (a) PBL of both patients and healthy donors could be expanded to large numbers (up to 2500-fold); (b) CLC derived from unfractionated PBL exhibited intermediate levels of cytotoxic activity against autologous and allogeneic fresh lung tumor cells and strong cytotoxicity toward several cultured adherent tumor cells; (c) whereas cultures originated from populations enriched for NK cells were highly cytotoxic against both adherent tumor target cells and against an NK-sensitive leukemic cell line (K562), cultures derived from populations depleted of NK cells were preferentially cytotoxic to adherent target cells; (d) clones of CLC were also strongly cytotoxic, but 2 out of 3 clones tested showed a narrower spectrum of target cytotoxicity than that of uncloned CLC; (e) CLC, when mixed with two carcinoma cell lines, were able to inhibit tumor growth in nude mice.
Digoxin elimination phase kinetics have been studied in 24 hospital in-patients (mean age 79 years), six of whom showed no evidence of digoxin toxicity. The others, with suspected toxicity, have been grouped according to the nature of the drug effects observed. Renal function, digoxin elimination half-life, apparent volume of digoxin distribution, and notional body content of digoxin have been compared between the groups. Apart from two hyperthyroid patients, the volumes of distribution averaged 6.1 1/kg. Toxic patients tended to have lower creatinine clearances, longer digoxin half-lives, and higher body contents of digoxin than the nontoxic, but the highest body contents were found in those with systemic toxicity. Thyrotoxicosis increases the apparent volume of digoxin distribution in the elderly.