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Biomedical subjects

M Reardon

Publications and source records attributed to M Reardon.

At least 37 records · Page 2Linked to original sources
PubMed1995

A survey of domiciliary consultations in medicine for the elderly.

The objective of this study was to assess the value of domiciliary consultations carried out by two hospital physicians for care of the elderly, using the resulting admission rates as one of the criteria. The action taken by the physicians on domiciliary visits was also studied. Data were collected retrospectively from all the domiciliary consultations done by the two departmental physicians from January 1992 to December 1992. From totals of 184 and 268 domiciliary consultations only 14.1% and 11.2% of patients seen respectively by consultant 1 and consultant 2 were admitted acutely to hospital. Overall, consultant 1 had something to offer in 92.4% of his domiciliary visits and consultant 2 took action in 81.3% of his domiciliary consultations. Most of the GP practices in the area used the service and only one practice was responsible for more than 10% of one consultant's domiciliary consultations. Domiciliary consultations form a useful service in medicine for the elderly and admission rates to hospital from these visits are low.

Aged↗
PubMed1993

Decision rules for the use of radiography in acute ankle injuries. Refinement and prospective validation.

OBJECTIVE: To validate and refine previously derived clinical decision rules that aid the efficient use of radiography in acute ankle injuries. DESIGN: Survey prospectively administered in two stages: validation and refinement of the original rules (first stage) and validation of the refined rules (second stage). SETTING: Emergency departments of two university hospitals. PATIENTS: Convenience sample of adults with acute ankle injuries: 1032 of 1130 eligible patients in the first stage and 453 of 530 eligible patients in the second stage. MAIN OUTCOME MEASURES: Attending emergency physicians assessed each patient for standardized clinical variables and classified the need for radiography according to the original (first stage) and the refined (second stage) decision rules. The decision rules were assessed for their ability to correctly identify the criterion standard of fractures on ankle and foot radiographic series. The original decision rules were refined by univariate and recursive partitioning analyses. MAIN RESULTS: In the first stage, the original decision rules were found to have sensitivities of 1.0 (95% confidence interval [CI], 0.97 to 1.0) for detecting 121 maleolar zone fractures, and 0.98 (95% CI, 0.88 to 1.0) for detecting 49 midfoot zone fractures. For interpretation of the rules in 116 patients, kappa values were 0.56 for the ankle series rule and 0.69 for the foot series rule. Recursive partitioning of 20 predictor variables yielded refined decision rules for ankle and foot radiographic series. In the second stage, the refined rules proved to have sensitivities of 1.0 (95% CI, 0.93 to 1.0) for 50 malleolar zone fractures, and 1.0 (95% CI, 0.83 to 1.0) for 19 midfoot zone fractures. The potential reduction in radiography is estimated to be 34% for the ankle series and 30% for the foot series. The probability of fracture, if the corresponding decision rule were "negative," is estimated to be 0% (95% CI, 0% to 0.8%) in the ankle series, and 0% (95% CI, 0% to 0.4%) in the foot series. CONCLUSION: Refinement and validation have shown the Ottawa ankle rules to be 100% sensitive for fractures, to be reliable, and to have the potential to allow physicians to safely reduce the number of radiographs ordered in patients with ankle injuries by one third. Field trials will assess the feasibility of implementing these rules into clinical practice.

Adolescent↗
PubMed1993

Attempted homicide in hospital.

Strychnine poisoning is reported in a patient who was the victim of attempted homicide in his home and in a General hospital. The diagnosis proved to be an elusive one over five months. The question of a primary psychiatric diagnosis, raised by the patient's wife proved to be an attempt by her to cover her crime. Medico-legal issues relating to the management of attempted homicide in hospital are discussed.

Family↗
PubMed1990

Expression of key enzymes of purine and pyrimidine metabolism in a hepatocyte-derived cell line at different phases of the growth cycle.

The effect of growth phase on enzymatic activities of the de novo and salvage pathways for purine and pyrimidine nucleotide synthesis was studied in a hepatocyte-derived cell line from the rat. The cells were in lag phase after plating for 36 h; log phase started at 48 h and persisted up to 120 h of culture. Then the cells stopped growing and entered into plateau phase (144 h). In non-proliferating cells (144 h of culture) the basal activities of the enzymes of purine de novo biosynthesis were 1.7- to 6.8-fold higher than in normal rat liver, those of pyrimidine de novo synthesis showed 0.6- to 30-fold increase in activity. The purine salvage enzymes were unchanged, and the pyrimidine salvage enzymes were 3.1- to 7.4-fold higher compared to normal liver. During the growth cycle all enzymes except the purine salvage enzymes, which did not change, showed a peak in activity at 72 h of culture (log phase). The increase in activity in log phase compared to plateau phase was 1.3- to 2.4-fold for purine de novo synthetic enzymes, 1.1- to 2.4-fold for pyrimidine de novo enzymes, and 1.4- to 4.7-fold for pyrimidine salvage enzymes. The specific activities of the enzymes in exponentially growing cells were comparable either to that in 24-h regenerating liver, or to that in hepatomas of low or medium growth rate. It was concluded that the enzymatic pattern and metabolic state of the cells shared some features with regenerating liver, others with tumors, although they were not tumorigenic after transplantation into athymic nude mice.

Animals↗
PubMed1990

The relationship between conductance and functional residual capacity during drug-induced bronchoconstriction.

UNLABELLED: We wondered if the inverse changes in airway conductance (Gaw) and functional residual capacity (FRC) during histamine (H) and acetylcholine (ACH) challenge are interrelated or occur at random. In 14 normal and 14 asthmatic subjects, we determined FRC and Gaw changes corresponding to changes in specific airway conductance (SGaw) around -40 percent produced by an aerosol of H or ACH inhaled quantitatively and with measured lung deposition. We also assessed the elastic recoil following H inhalation (5A). We found that in 11 normal and nine asthmatic subjects, after H or nine normal and 11 asthmatic subjects after ACH, Gaw and 1/FRC were linearly and directly related (p less than 0.05). The steepness of this slope was directly related to the resting Gaw values. A similar relation was uncovered in the literature for asthmatic patients at rest or during recovery from natural asthma. As the elastic recoil was normal and did not change after H, it could not explain delta FRC at delta SGaw of -40 percent. IN CONCLUSION: (1) during H or ACH challenge, Gaw-FRC relationship in normal or asthmatic subjects tends to be hyperbolic and dependent on resting Gaw; (2) such a relationship is seemingly present in other bronchoconstrictor responses with a different pathogenesis; and (3) during bronchoconstriction, as Gaw vs FRC is no longer linear, SGaw becomes volume dependent.

Acetylcholine↗
PubMed1989

The effects of hypoxemia on myocardial blood flow during exercise.

We evaluated the adequacy of regional and transmural blood flow during exercise and rapid pacing after 1 wk of hypoxemia. Seven mature mongrel dogs were made hypoxemic (mean O2 saturation = 72.4%) by anastomosis of left pulmonary artery to left atrial appendage. Catheters were placed in the left atrium, right atrium, pulmonary artery, and aorta. Atrial and ventricular pacing wires were placed. An aortic flow probe was placed to measure cardiac output. Ten nonshunted dogs, similarly instrumented, served as controls. Recovery time was approximately 1 wk. Cardiac output, mean aortic pressure, and oxygen saturation were measured at rest, with ventricular pacing, atrial pacing, and with treadmill exercise. Ventricular and atrial pace and exercise were at a heart rate of 200. Right ventricular free wall, left ventricular free wall, and septal blood flow were measured with radionuclide-labeled microspheres. Cardiac output, left atrial blood pressure, and aortic blood pressure were similar between the two groups of dogs in all testing states. Myocardial blood flow was significantly higher in the right and left ventricular free wall in the hypoxemic animals during resting and exercise testing states. Myocardial oxygen delivery was similar between the two groups of animals. Pacing resulted in an increase in myocardial blood flow in the control animals but not the hypoxemic animals.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Regulation of carbamoyl-phosphate synthase II.

Evidence was provided that in rat liver synthase II activity, amount and turnover were regulated primarily by insulin. When rats were starved, synthase II activity and the immunotitratable enzyme amount markedly decreased; refeeding restored enzyme activity and amount to normal range. The changes in activity and amount were paralleled with alterations in the level of circulating insulin in the plasma. When starved rats were treated with anti-insulin serum before and during refeeding, the animals consumed the food, but the rise in synthase II activity was prevented. In diabetic rats, the activity and amount of synthase II in the liver markedly decreased and insulin treatment restored them to normal range. Actinomycin treatment prevented the refeeding and the insulin-induced rise in synthase II activity and amount. Study of the turnover of synthase II showed that in starvation the rate of synthesis decreased and refeeding restored the enzyme synthetic and degradation rates to normal range. In the diabetic rat, synthase II synthetic rate markedly decreased, and the degradation rate increased. Insulin returned the synthetic and catabolic rates to normal livers. In rapidly growing rat hepatoma 3924A, synthase II activity and amount were elevated 9- to 10-fold. Turnover studies showed that the synthetic rate in hepatoma 3924A was approximately 10-fold higher than that of normal liver. The catabolic rates of synthase II were similar in the liver and hepatoma. Thus, the increased activity and amount of synthase II in the hepatoma was due primarily to an increased rate of enzyme biosynthesis. Evidence was presented that in starvation and diabetes and on refeeding and insulin administration there is very little or no change in the enzymic activity, amount and turnover of hepatoma synthase II. The marked contrast between the turnover rate of hepatoma 3924A synthase II activity and that of the normal liver enzyme in starvation and in diabetes is under investigation. This overview of the behavior of activity, amount and turnover of synthase II in liver and hepatoma 3924A provides evidence of the important role of insulin in regulation of liver synthase II and of the apparent lack of responsiveness of the hepatoma enzyme to insulin concentrations. The precise details of the experimental procedures and the enzymic results will be published elsewhere.

Animals↗
PubMed1985

Reduced triglyceride formation from long-chain polyenoic fatty acids in rat hepatocytes.

The mechanism for the marked reduction in hepatic triglyceride secretion when rats are fed fish oils was explored in studies with isolated rat hepatocytes. Hepatocytes obtained from Sprague-Dawley rats fed either chow or fish oil or safflower oil were incubated in the presence of [3H]-glycerol to estimate triglyceride formation. In some experiments, various fatty acids, complexed to albumin, were added to the incubations. Similar experiments were carried out with hepatocytes from a genetic strain of hypertriglyceridemic, obese rats. In the absence of added fatty acid, hepatocytes from fish oil-fed rats produced and secreted substantially less triglyceride than cells from safflower oil-fed rats. However, the addition of 2 mmol/L Na oleate stimulated triglyceride formation similarly in both types of hepatocytes. When hepatocytes from chow fed rats were incubated with fatty acids of increasing chain length and unsaturation (oleate, linolenate, arachidonate, eicosapentaenoate, and docosahexaenoate), the latter two, which characterize the fish oil used, almost totally suppressed triglyceride formation. Coincubation with oleate partly reversed this effect. Hepatocytes from the hypertriglyceridemic rats synthesized significantly more triglyceride than hepatocytes from normal rats; however triglyceride formation was markedly reduced also in this strain of rat by feeding fish oil or by adding docosahexaenoate to hepatocytes in vitro. These studies confirm previous conclusions with perfused livers from fish oil-fed rats that showed diminished triglyceride production and secretion. These findings suggest that diversion of polyenoic acids from pathways of esterification is a major factor in the triglyceride lowering effect of fish oils.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1982

Standardization of the double-antibody method for IgE determination: use of different monoclonal IgE as tracer, immunogen or standard.

We wanted to determine whether the competitive radioimmunoassay for IgE is influenced by various combinations of three monoclonal IgE (IgEND, IgEPS, IgESHA) used as tracer or standard, and anti-IgEND and anti-IGEPS as first antibody. When the immunogen for the first antibody was identical with the monoclonal tracer or standard IgE, the latter two bound preferentially to the first antibody. These unusual assays led to inhibition curves that ran in parallel to those produced by usual assays, i.e. assays in which the tracer and the immunogen were different monoclonal IgE and the standard was a polyclonal IgE. When serum samples were analyzed for their IgE content, the unusual assay produced values that were linearly related to those produced by a usual or another, unusual, assay. However, the values of IgE produced by a usual assay were, in general, significantly different from those obtained by unusual assays. We conclude that as suspected, but never demonstrated before, the competitive assay for IgE requires the use of two different monoclonal IgE as tracer and immunogen; application of unusual assays requires their prior calibration against a usual assay.

Animals↗
PubMed1980

Turnover of apoproteins A-I and A-II of high density lipoprotein and the relationship to other lipoproteins in normal and hyperlipidemic individuals.

The kinetics of the major apoproteins of high density lipoproteins (HDL), A-I(apoA-I) and A-II(apoA-II), were studied from the specific activity-time curves of these apoproteins, after reinjection of radioiodine-labeled HDL. In all 20 subjects, HDL apoprotein kinetics conformed to a two-pool model. The total fractional removal rates for the two apoproteins were similar, although the irreversible fractional removal rate appeared to be slightly greater for apoA-I. The mean transport for A-I and A-II was 12.2 mg/kg/day and 5.0 mg/kg/day, respectively. The mass of the apoprotein pools was strongly correlated with apoprotein production rate and also, to a lesser degree and inversely, with the irreversible fractional catabolic rate. Transport was directly correlated with body weight. Higher fractional catabolic rates, including the transfer rates between the two pools, were observed in five hypertriglyceridemic subjects; in contrast, five subjects with familial hypercholesterolemia tended to show lower fractional catabolic rates. These findings were supported by (1) a strongly positive correlation between the transport rates of HDL A-I and of very low density lipoprotein (VLDL) apoB, determined simultaneously in 10 subjects; and (2) a significant inverse correlation between the irreversible fractional removal rate of HDLA-I and the concentration of low density lipoprotein (LDL) apoB, measured in 15 subjects. These observations underline the metabolic interrelationships of the major lipoprotein classes. Two subjects with familial hyperalphalipoproteinemia showed enlarged pool sizes, but normal transport, with irreversible fractional removal rates that were in the lower range for the group of 20 subjects.

Adult↗
PubMed1979

In vivo transfer of cholesteryl esters from high density lipoproteins to very low density lipoproteins in man.

The fate of cholesteryl esters in high density lipoprotein (HDL) was studied to determine whether the transfer of esterified cholesterol from HDL to other plasma lipoproteins occurred to a significant extent in man. HDL cholesteryl ester, labelled in vitro with [3H] cholesterol, was injected into human subjects. Labelling of cholesteryl esters in very low density (VLDL) occurred rapidly and by 3 h, the esterified cholesterol in VLDL reached peak specific radioactivity. The removal rate of cholesteryl esters from HDL appeared to be exponential and of the order of 0.2/h; calculation of the apparent flux was about 150 mg/h which approximates reported values for total cholesterol esterification in human plasma in vivo. The rapid rate of labelling of VLDL from HDL suggests that the transfer of HDL cholesteryl esters to VLDL may represent a significant pathway for the disposal of HDL cholesterol.

Cholesterol↗
PubMed1979

Sucrose-induced changes in VLDL- and LDL-B apoprotein removal rates.

Dietary sucrose has been shown to increase triglyceride transport in very-low-density lipoproteins (VLDL), but it is not known whether the metabolism of the entire particle is affected. Measurements were therefore carried out on VLDL-B apoprotein flux and removal rate before and after the consumption of high sucrose diets (55% of calories). Autologous 125I-labeled VLDL were injected and the specific activity-time curves analyzed by two-pool kinetics. Two kinds of response to sucrose were seen. In two subjects, the pool of VLDL-B apoprotein decreased by 20% and 14% (despite increased fluxes) due to substantial increases in removal rates of 42% and 116%. In four subjects, pool size expanded by 154%, 426%, 50% and 105%, primarily as the result of decreased removal rates (decreases of 55%, 67%, 30%, and 43%). Changes in flux were inconstant, suggesting that accumulation of VLDL particles was related to delayed clearance rather than to increased formation. This may reflect the longer time required to remove the larger load of triglyceride from each particle. The catabolic rate of low-density lipoprotein (LDL) was also measured in five subjects: in four, the clearance of LDL increased with sucrose and was associated with decreases in LDL-B apoprotein and plasma cholesterol.

Administration, Oral↗