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Biomedical subjects

M Elia

Publications and source records attributed to M Elia.

At least 181 records · Page 10Linked to original sources
PubMed1993

The independent metabolic effects of halothane and isoflurane anaesthesia.

Twelve healthy, unpremedicated women scheduled for total abdominal hysterectomy were given either isoflurane (n = 6) or halothane (n = 6) anaesthesia. They all received general anaesthesia for a period of 3 h, with surgery being carried out only in the last hour. The anaesthesia consisted of thiopentone, pancuronium and a mixture of oxygen-enriched air (FiO2 = 34%) supplemented with 1 MAC of either isoflurane or halothane. The patients were maintained normothermic, and with an arterial SaO2 above 95% throughout the period of the study. The following measurements were made before, during and after anaesthesia (with and without surgery): oxygen consumption (VO2), carbon dioxide production (VCO2); circulating concentrations of various hormones (insulin, growth hormone and cortisol); various metabolites; selected amino acids and albumin; forearm arterio-venous concentration difference of glucose, lactate, free fatty-acids and selected amino acids (four patients in each group). Whole body VO2 decreased significantly by over 20% during anaesthesia (with or without surgery), P < 0.05). Although the circulating concentration of most amino acids showed little or no change during anaesthesia alone, there was a tendency for the flux of most metabolites to decrease, and this persisted during surgery (P < 0.05). During anaesthesia alone there was a twofold reduction in the plasma cortisol concentration (P < 0.05), and a decrease in albumin concentration (P < 0.01). With the onset of surgery, plasma cortisol concentration increased rapidly (in association with several other hormones and metabolites) but hypoalbuminemia persisted.

Adult↗
PubMed1993

Techniques for the measurement of body composition: a practical guide.

This paper discusses some of the practical aspects of both reference body composition methods (densitometry, isotope dilution methods, in vivo neutron activation analysis, dual energy X-ray absorptiometry, computerized tomographic scanning and magnetic resonance imaging) and bedsides or field techniques (weight and height indices, skinfold thicknesses impedance/resistance, near infra-red interactance and 24 hour creatinine excretion). Some techniques measure gross composition, in terms of fat and fat-free mass, or the components of fat-free tissue, such as water, mineral and protein, while other methods measure the mass of individual tissues, organs or body segments. The choice of a specific method for a particular study depends on various considerations including accuracy, precision, subject acceptability, convenience, cost, radiation exposure, and the need for observer training. The relative advantages and disadvantages of each method are discussed with these considerations in mind.

Absorptiometry, Photon↗
PubMed1993

Artificial nutritional support in clinical practice in Britain.

Malnutrition is common in hospitalised patients. It often develops insidiously and its diagnosis is frequently delayed or missed. A multidisciplinary nutrition support team can improve the quality of nutritional support, reduce inappropriate feeding, reduce the complications associated with enteral and parenteral nutrition, and so improve clinical outcome and reduce hospitalisation. These improvements have obvious financial advantages, yet only a minority of British hospitals (25-30%) has a nutrition team. The increasing use of parenteral and enteral nutrition at home, which represents one of the most important areas of recent developments in artificial nutritional support, also has financial and clinical advantages, but the management of such patients is also less than optimal. Better education and greater awareness of nutritionally related problems, as well as changes in the local and national infrastructure of nutrition support services, are required to improve the quality of care and the clinical outcome for patients being treated by parenteral and enteral nutrition in hospital and at home.

Enteral Nutrition↗
PubMed1992

The acute-phase response to turpentine-induced abscesses in malnourished rats at different environmental temperatures.

An assessment was made of the independent effect environmental temperature (13, 21, and 30 degrees C) and either protein deficiency or energy deficiency on the metabolic response of rats that had aseptic abscesses induced by subcutaneous injections of turpentine. Measurements of food intake, alpha 2-macroglobulin (alpha 2-M; a major acute-phase protein in the rat), albumin, and various circulating metabolites were made 48 hours after turpentine injection in animals acclimatized at 13, 21, and 30 degrees C and compared with pair-fed controls. Despite differences in basal circulating albumin concentrations between controls and protein deficient rats (P less than .001), turpentine produced a similar reduction in all groups of animals (approximately 10 g/L), independent of environmental temperature. The alpha 2-M response to turpentine was attenuated in all protein-deficient animals and also in the energy-restricted animals at 13 degrees C. The increase in circulating 3-hydroxybutyrate (BOH) and nonesterified fatty acid (NEFA) concentrations, which normally occur with reduced dietary intake, was reduced in the turpentine-injected animals to an extent that depended on prior dietary intake. It is concluded that the metabolic response, particularly the acute-phase protein response, to a standard form of "injury" is affected by protein deficiency and possibly by energy restriction under adverse environmental temperature.

Abscess↗
PubMed1992

The potential use of dual frequency bioimpedance in predicting the distribution of total body water in health and disease.

The distribution of water between extracellular fluid (ECF; measured by the inulin dilution technique) and intracellular fluid (ICF; calculated as the difference between total body water, which was measured by the deuterium dilution technique, and ECF) was measured in 12 healthy subjects. The results were compared with predictions made by anthropometry and whole body impedance obtained at 1kHz (Z(1)) and 50 kHz (Z(50)). Z(1) and Z(50) were also measured in 82 health subjects and 27 patients without clinically detectable oedema, and in 10 patients with oedema. Anthropometry and height(2)/Z(1) showed similar correlations with inulin space (r = 0.64, SEE = 1.74 L and r = 0.65, SEE = 1.75 L respectively). The ratios of Z (1)Z (50) in oedematous patients (1.03 +/- 0.02), which were universally lower than those obtained in normal subjects (1.18 +/- 0.04), overlapped with those obtained in patients without oedema (1.11 +/- 0.05). The study suggests that in this group of normal subjects low frequency bioimpedance measurements are not superior to anthropometric estimates of ECF. They also suggest a limitation in the use of the dual frequency bioimpedance meter to distiguish between patients with and without oedema.

Journal Article↗
PubMed1992

Correspondence.

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Letter↗
PubMed1992

Resting energy expenditure and body composition following cerebro-vascular accident.

The aim of this study was to measure resting energy expenditure (REE) in patients routinely admitted to hospital following a cerebro-vascular accident (CVA). The REE of 15 patients (8 female; 7 male) was measured using indirect calorimetry 24-72 hours after the CVA; 11 patients (7 female; 4 male) were measured again 10-14 days later. Body composition was assessed using skin-fold thickness, near infra-red interactance and bioelectrical impedance techniques. Initial REE in females was 1133 kcal/day (+/-67) and in males 1526 kcal/day (+/-111). There was little or no difference in REE or body composition between the first and second measurements. REE was between 95%-107% of the values predicted by 10 reference tables and equations and up to 118% of that predicted by another. We conclude that the total energy requirements of patients following a stroke are not high, probably because of decreased physical activity and changes in muscular tone subsequent to CVA.

Journal Article↗
PubMed1992

Nutrient utilisation in muscle and in the whole body of patients receiving total parenteral nutrition.

Forearm metabolite exchange was assessed by the arterio-venous catheterization technique in 5 parenterally fed patients (weight 55.22 kg +/- 4.18 kg; height 1.71 m +/- 0.04 m), who received an 'all-in-one' nutrition regimen whilst in remission from Crohn's disease. All patients received 12.8 g N, 4725 kJ from carbohydrate and 4200 kJ from fat (10416 kJ total energy). The exchanges were related to nutrient oxidation and nutrient balances in the whole body as assessed by indirect calorimetry and nitrogen excretion. At rest, the subjects were found to be in positive balances for carbohydrate (+0.78 +/- 0.13 kJ/min), fat (+1.85 +/- 0.26 kJ/min) and protein (+0.240 +/- 0.04 kJ/min). Resting forearm muscle was also in positive amino acid balance and positive carbohydrate balance. Despite the large estimated uptake of glucose by forearm muscle (+1860 +/- 84 nmol/100 ml tissue/min) there was no net release of pyruvate and lactate. Glutamate and the branched chain amino acids (BCAA) were the dominant amino acids taken up by muscle (26% and 30% of total uptake respectively) and glutamine was the dominant amino acid carrying nitrogen out of muscle (78% of total amino acid nitrogen release). The energy taken up by muscle as non-esterified fatty acids, triacylglycerol and ketone bodies was small relative to that associated with glucose uptake. The results suggest that during the hypercaloric parenteral nutrition regimen, a) increased peripheral glucose uptake is not necessarily associated with increased release of glycolytic products, b) in the absence of glutamine intake for at least 10 days, muscle retains enough capacity to synthesise and release sufficient quantities of glutamine so that it remains the dominant amino acid carrying nitrogen out of muscle, c) despite the use of the intravenous route for administration of nutrients, and unusual amino acid composition of the regimen, the overall pattern of forearm metabolism bears many similarities to that which occurs after a mixed meal in normal subjects.

Journal Article↗
PubMed1992

Tuberous sclerosis and Down syndrome: a casual association?

This paper reports on the clinical, neurophysiological and neuroradiological characteristics of a patient with Down syndrome unusually associated with tuberous sclerosis. In particular, epilepsy is investigated in detail and its polygraphic study and etiopathological factors are discussed. The most interesting findings are those related to the presence of a structural abnormality of the rolandic-parietal cortex, bilaterally, in the form of pachygyria.

Adult↗
PubMed1992

Four-component model for the assessment of body composition in humans: comparison with alternative methods, and evaluation of the density and hydration of fat-free mass.

1. Body composition was assessed in 28 healthy subjects (body mass index 20-28 kg/m2) by dual-energy X-ray absorptiometry, deuterium dilution, densitometry, 40K counting and four prediction methods (skinfold thickness, bioelectrical impedance, near-i.r. interactance and body mass index). Three- and four-component models of body composition were constructed from combinations of the reference methods. The results of all methods were compared. Precision was evaluated by analysis of propagation of errors. The density and hydration fraction of the fat-free mass were determined. 2. From the precision of the basic measurements, the propagation of errors for the estimation of fat (+/- SD) by the four-component model was found to be +/- 0.54 kg, by the three-component model, +/- 0.49 kg, by deuterium dilution, +/- 0.62 kg, and by densitometry, +/- 0.78 kg. Precision for the measurement of the density and hydration fraction of fat-free mass was +/- 0.0020 kg/l and +/- 0.0066, respectively. 3. The agreement between reference methods was generally better than between reference and alternative methods. Dual-energy X-ray absorptiometry predicted three- and four-component model body composition slightly less well than densitometry or deuterium dilution (both of which greatly influence these multi-component models). 4. The hydration fraction of fat-free mass was calculated to be 0.7382 +/- 0.0213 (range 0.6941-0.7837) and the density of fat-free mass was 1.1015 +/- 0.0073 kg/l (range 1.0795-1.1110 kg/l), with no significant difference between men and women for either. 5. The results suggest that the three- and four-component models are not compromised by errors arising from individual techniques.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorptiometry, Photon↗
PubMed1992

Effect of aseptic abscesses in protein-deficient rats on the relationship between interleukin-6 and the acute-phase protein, alpha 2-macroglobulin.

1. Rats established on a normal (20% protein) diet or a protein-deficient (3% protein) diet were given either a subcutaneous injection of turpentine (5 ml/kg), which induces formation of aseptic abscesses, or saline. Plasma samples were obtained at timed intervals (0-14 days) after the injection for determination of albumin, total protein, alpha 2-macroglobulin (a major acute-phase protein in the rat) and interleukin-6 concentrations. The magnitude and pattern of the acute-phase protein response was then compared with the local inflammatory reaction, assessed histologically, and with changes in the circulating concentration of interleukin-6, which is an important mediator of the acute-phase protein response. 2. After turpentine injection there was an early fall in the plasma albumin and total protein concentrations in both normal and protein-deficient rats. After 12 h the total protein concentration increased in both groups of animals reaching a peak at about 48 h, whereas the plasma albumin concentration continued to fall reaching a minimum at 48 h. The main alpha 2-macroglobulin response was delayed and attenuated in the protein-deficient rats (onset 9 versus 24 h, peak concentration 8.95 +/- 0.5 versus 5.33 +/- 0.75 g/l, P < 0.01, and area under the concentration-time curve 18.43 +/- 2.13 versus 7.96 +/- 1.48 g/l-1 days, P < 0.01, in the normal group and protein-deficient group, respectively). 3. The circulating interleukin-6 concentration showed a transient early rise at 1 h, and was followed by a larger more sustained peak at 6-48 h.(ABSTRACT TRUNCATED AT 250 WORDS)

Abscess↗
PubMed1992

The magnitude of the acute phase protein response is attenuated by protein deficiency in rats.

We assessed the growth rate and changes in plasma albumin, total protein and alpha 2-macroglobulin concentrations (a major acute phase protein in rats) before and after a subcutaneous injection of turpentine (0.5 mg/kg body wt) in groups of rats receiving one of a series of protein-deficient diets (protein concentrations of 0.5, 1.5, 3.0, 4.5 or 6.0 g/100 g) or a diet containing an adequate level of protein (20 g/100 g) for maximal growth. Increasing protein deficiency in the different groups of animals reduced the basal albumin and total protein concentrations and attenuated the total protein and alpha 2-macroglobulin responses to turpentine. Increasing protein deficiency delayed the time taken for alpha 2-macroglobulin to reach peak concentrations post-injection and its return to basal concentrations. The turpentine-induced hypoalbuminemia was similar in all groups of animals (approximately 10 g/L depression) but restoration to values that were present before turpentine injection was increasingly delayed with increasing protein deficiency. The magnitude of the acute phase response (peak alpha 2-macroglobulin concentration) was found to be directly related to growth rate (r = 0.70, P less than 0.001). We concluded that protein deficiency can alter the pattern and magnitude of the acute phase responses in circulating protein concentrations to an extent that is dependent on the severity of protein deficiency.

Acute-Phase Proteins↗
PubMed1992

Assessment of the composition of major body regions by dual-energy X-ray absorptiometry (DEXA), with special reference to limb muscle mass.

Dual-energy X-ray absorptiometry (DEXA) has been used to assess and compare the composition of whole body and major body regions in 12 female (weight, 56.9 +/- 6.2 kg; BMI, 17-25 kg m-2) and 16 male (weight, 73.1 +/- 9.6 kg; BMI, 20-28 kg m-2) healthy subjects. Standard deviations (and % coefficients of variation) of the differences between repeated measurements of fat ranged from 0.11 kg (9.0%) for arms to 0.42 kg (3.0%) for whole body; for arm bone mineral, 0.01 kg (2.0%), and for fat-free soft tissue of the whole body, 0.42 kg (0.8%). Limb muscle mass was estimated using a new theoretical model of body composition, and the corresponding precision ranged from 0.15 kg (3.8%) to 0.27 kg (1.5%) for arms and total limb muscle mass, respectively. Proportions of each region consisting of fat were greater in females than in males (range, 20-31% vs. 16-18%), respectively, but the ratio of trunk to leg fat was lower (34:49% vs. 46:38%, respectively). Regional proportions of bone were similar between the sexes (all in the range 2.9-5.6%, for both females and males). Mean total limb muscle masses were 14.2 kg (arms, 2.8 kg; legs, 11.4 kg) for females and 22.2 kg (arms, 4.8 kg; legs, 17.4 kg) for males, which were 33.6% and 36.0% of fat-free mass, respectively. The correlation coefficients between limb muscle (DEXA) and other indices of muscle mass were: for DEXA vs. total body potassium, 0.90 (SEE 1.1 kg muscle mass) to 0.94 (1.6 kg); and for DEXA vs. anthropometry, 0.43 (1.2 kg) to 0.85 (1.3 kg). Those for limb volume (DEXA) vs. anthropometric volume, 0.91 (0.78 1) to 0.94 (1.91 1). It is concluded that DEXA enables the valid and reproducible estimation of fat, fat-free soft tissue, bone, and limb muscle mass.

Absorptiometry, Photon↗
PubMed1992

Measurement of bicarbonate turnover in humans: applicability to estimation of energy expenditure.

Bicarbonate turnover and energy expenditure were assessed in six healthy male volunteers, by the use of a constant infusion of radiolabeled bicarbonate (NaH14CO3) administered over 36 h, while the volunteers were confined to a whole body indirect calorimeter. Recovery and dilution of isotope were assessed from measurements made on continuous collections of CO2, entering and leaving the calorimeter, urine, and intermittent spot breath and saliva samples. Mean recovery of infused label in gaseous CO2 was 95.6 +/- 1.1% (SD) between 12 and 36 h. Applying a 95% mean recovery of label to each subject individually enabled the use of integrated mean specific activity of CO2 in spot breath and urine samples to predict measured net CO2 production and energy expenditure to within about +/- 6%. Estimates based on urinary measurements were compromised slightly by the exchange of label through the bladder wall (this was dependent on pH and volume of urine). It is concluded that this constant-infusion labeled bicarbonate method offers a potentially useful means of assessing net CO2 production and total energy expenditure over the short term (e.g., 1-3 days).

Adult↗