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Biomedical subjects

M Elia

Publications and source records attributed to M Elia.

At least 199 records · Page 11Linked to original sources
PubMed1992

Onlay technique for occipitocervical fusion.

Twenty-eight occipitocervical fusions using the onlay technique were performed in 27 patients ranging in age from 13 to 77 years (average age, 47.6 years). The indications for fusion included neurologic involvement from atlantoaxial instability associated with superior migration of the odontoid and destructive changes at the occiput-C1-C2 articulation, causing pain unrelieved by conservative treatment. Preoperative diagnoses included rheumatoid arthritis, congenital anomalies, posttraumatic, failed C1-C2 fusions, ankylosing spondylitis, and tumor. A standard posterior exposure of occiput-C1-C2 was used, and iliac crest bone graft was placed over the area to be fused. Postoperative immobilization consisted of skull tong traction, minerva jacket, and halo apparatus. There were no neurologic complications, two superficial wound infections, and minor difficulties with halo loosening. There was one perioperative death. Primary fusion was obtained in 89% of patients at an average of 12.8 weeks. Occipitocervical fusion by the onlay technique is safe, requires no internal fixation, and has a high success rate when compared with other methods of obtaining fusion in the occipitocervical region.

Adolescent↗
PubMed1991

Factors affecting the stability of L-glutamine in solution.

The degradation rate of L-glutamine in water, various buffers, and intravenous solutions was assessed over a period of 2 weeks. Measurements were made at various temperatures (22-24 degrees C, and 4 degrees C and -80 degrees C) and pH, and also in the presence and absence of light and oxygen (intravenous solutions only). At 22-24 degrees C, the degradation rate of glutamine was variable depending on the type of solution used (0.23% in water pH 6.5; 0.22% in dextrose/water [15% w/v]; 0.8% in mixed total parenteral nutrition (TPN) solution), and on the pH, molarity and type of buffer used. The degradation rate was essentially unaffected by light and O(2). The degradation rate of L-glutamine in the intravenous solutions was less than 0.15%/day at 4 degrees C, minimal at -20 degrees C (<0.03%/day), and undetectable at -80 degrees C. Glutamine degradation resulted in the equimolar formation of ammonia and no associated formation of glutamate. It is concluded that (a) glutamine degradation in solution is variable due to the effect of physico-chemical factors, and (b) glutamine degradation in TPN solutions is sufficiently slow, especially during storage at 4 degrees C or below, to consider its inclusion in such solutions, for clinical use.

Journal Article↗
PubMed1991

The stability of L-glutamine in total parenteral nutrition solutions.

An assessment was made over a period of 14 days of the rate of glutamine degradation in different intravenous solutions kept at 22-24 degrees C, 4 degrees C, -20 degrees C and -80 degrees C. At room temperature (22-24 degrees C) degradation rates in mixed parenteral nutrition solutions and aminoacid/dextrose solutions ranged from 0.7-0.9%/day, in Perifusin 0.6%/day, and in dextrose alone as low as 0.15%/day. At 4 degrees C, glutamine degradation was <0.1-0.2%/day in all solutions examined, at -20 degrees C it was minimal (<0.04%/day) and at -80 degrees C, it was undetectable. Glutamine degradation was found to be associated with the formation of equimolar quantities of ammonia. No glutamate formation was detected. It is concluded that it is possible to store glutamine in parenteral nutrition solutions kept at 4 degrees C, with about 2% loss over a period of 14 days. The degradation is sufficiently slow to consider the use of intravenous glutamine in nutritional therapy.

Journal Article↗
PubMed1991

Intravenous carbohydrate over-feeding: a method for rapid nutritional repletion.

Forty-four measurements of resting energy expenditure (REE) and respiratory quotient (RQ), and sequential measurements of body composition and nitrogen excretion were made in a cachectic male patient with inactive Crohn's disease, who was repleted with intravenous nutrition alone, over a period of 62 days. The initial energy intake (EI) of 10 MJ/day was increased to 21 MJ/day by three stepwise increments ( approximately 4MJ) in the glucose content of the feed. REE increased from 4.2 to 6.8 kJ/min, and body weight from 53 to 76kg. REE rose by a progressively greater amount with each increment in energy intake (DeltaREE DeltaEl = 0.12 to 0.26 ). The RQ increased progressively to a value up to 1.19 and persisted above 1.0 even 9h after the feed was stopped. The results suggest that the increase in REE a) was due to a combination of increasing lean body mass and increasing diet-induced thermogenesis, b) dissipated only a small proportion of the total energy infused, and c) was associated with net lipid synthesis from carbohydrate whilst on and off the feed. The results are discussed in relation to the energy equivalent of ATP and the circulating concentrations of insulin and the flux of substrates across forearm tissue.

Journal Article↗
PubMed1991

The effect of endotoxin and turpentine administration on intestinal permeability in the rat.

Intestinal permeability in 4-week-old rats has been assessed by the dual sugar (lactulose/mannitol) permeability test before and for two days after induction of systemic inflammation by various endotoxins and turpentine. Evidence of an inflammatory response to these agents was provided by marked reductions in food consumption and growth rate, hypoalbuminaemia, and a large increase in the plasma concentration of the acute-phase protein alpha-2-macroglobin. Abnormal values for intestinal permeability occurred only in animals which had been injected with E. coli 0111:B4 endotoxin. Neither turpentine nor the other endotoxins produced any detectable effect. Within 2-7h of the first exposure to a low dose, (3mg/kg) of either phenol or trichloroacetic extracts of E. coli 0111:B4 endotoxin, the lactulose:mannitol (L M ) ratio was elevated by 32% and 50% respectively (p < 0.05), but the rise was not sustained despite continued twice-daily injections of endotoxin. Administration of a higher dose, (10 mg/kg twice daily, phenol extract) resulted in diarrhoea, and a greater more persistent increase in the L M ratio; 115% (p < 0.05) 2-7h after the first injection, and 49% above control values, (p < 0.01) 24h later. The increase in L M ratio appeared to be due to a decrease in mannitol excretion. Total urinary lactulose also tended to fall, especially in rats given the high dose of endotoxin. It is concluded that a systemic inflammatory response does not necessarily lead to a change in intestinal permeability as measured by the dual sugar permeability test. The transient permeability changes observed following E. coli 0111:B4 administration may be a specific reaction to this material rather than to a more general systemic stimulus.

Journal Article↗
PubMed1991

Intestinal permeability in man: effects of acute systemic infections.

Intestinal permeability was assessed (within 24-48h of admission to hospital) in 7 patients suffering from acute infections, mainly pneumonia. The permeability test involved administering an oral solution containing a mixture of lactulose (10 g) mannitol (5 g and 0.5 microCi) and (51)Cr-EDTA (30 microCi), and collecting urine samples before, and between 0-6, 6-12 and 12-24 h after dosing. The excretion of the markers was compared with the results obtained from 24 normal or control subjects and 15 patients with coeliac disease. None of the markers were excreted in significantly different amounts in the infected patients compared to the control subjects. In contrast, the coeliac patients excreted (0-6 h) four-fold more lactulose, three-fold more (51)Cr-EDTA and two-fold less mannitol than the normal subjects. The ratio of lactulose: mannitol and (51)Cr-EDTA: mannitol were therefore six- to eight-fold greater in the coeliac patients than in the normal subjects. The results confirm the sensitivity of the test for detecting the presence of an enteropathy but provide no evidence of a change in intestinal permeability in systemic infections studied under the stated conditions.

Journal Article↗
PubMed1991

Assessment of changes in total body water in patients undergoing renal dialysis using bioelectrical impedance analysis.

This study aimed to assess whether changes in fluid can be accurately predicted from the change in whole-body impedance with an appropriate correction for the conductor length (i.e. height). Eight studies to measure changes in impedance were performed on six patients during dialysis. The measured loss of fluid from the beginning to the end of dialysis (1174+/-706ml) agreed well with the change in body weight (1188+/-768kg). The regression lines of the plot of change in height(2)/impedance versus loss of fluid for each subject had correlation coefficients ranging from 0.880-0.999, but there was a four-fold variation in the slopes of the different curves. The mean +/- SD change in height(2)/impedance during the removal of 0.5, 1 and 2l of water was 1.75+/-0.96, 3.41+/-1.55 and 6.72+/-2.91 m(2)/ohms respectively. The total change in body water, calculated by a variety of prediction equations, overestimated the loss of fluid by a mean of between 86 and 100%. The lack of a fixed relationship between changes in impedance and changes in body water precludes the use of the impedance technique as a means of accurately assessing small fluid changes in this patient group.

Journal Article↗
PubMed1991

The effect of severe dietary restriction on intramuscular glutamine concentrations and protein synthetic rate.

An investigation was carried out to examine the relationship between fractional muscle protein synthetic rate (FSR) and intramuscular glutamine concentration ({GLN}(i)) in rats that had a dietary intake which was deficient in both protein and energy. Young male rats (38 days old) were fed for 48 h on either 1) 25% of the ad lib intake of a 20% protein diet, or 2) glucose alone, sufficient to provide the same energy intake as in 1). In a separate study, 33 day old rats were starved completely for 48 h. Appropriate controls were included in both studies. Muscle FSR, which was reduced by 40% in both groups of energy restricted rats (P<0.001), was associated with a small increase in {GLN}(i) (P<0.05). Starvation produced a 60% reduction in FSR (P<0.01) and a 45% (P<0.05) reduction in {GLN}(i). It is concluded that reductions in muscle protein synthesis can occur by mechanisms independent of intramuscular glutamine concentration.

Journal Article↗
PubMed1991

Serum interleukin 6 (IL-6) - effect of surgery and under-nutrition.

We aimed to investigate the role of IL-6 as a mediator of the acute phase response (APR) in man; to assess the effect of under-nutrition on serum/plasma IL-6 levels; and to assess the value of IL-6 as a prognostic indicator by measuring IL-6 in timed venous samples taken from surgical patients and from protein deficient and control rats post-turpentine injections. Serum IL-6 rose in all surgical patients within 2-4h of incision. Peak levels differed among the groups and correlated significanlly with duration of surgery (r = 0.75, p<0.001). CRP did not rise in some patients and discriminated poorly among the groups. Patients who developed complications had higher IL-6 values at 24h post-incision than those making uneventful recoveries. Protein depleted rats had a significantly slower IL-6 response than controls. Serum IL-6 is a sensitive, early marker of tissue damage which might help to predict the development of surgical complications. Under-nutrition affects the IL-6 response in rats and may do so in man.

Editorial↗
PubMed1991

Modulation of the interictal epileptiform EEG activity during sleep: from oscillations to complex dynamics.

Polygraphic sleep recordings (EEG, EMG, and EOG) were performed in two groups of epileptic subjects, six with fragile-X syndrome and six with symptomatic epilepsy. Recordings were visually scored for sleep stages and number of spikes/min. Subjects with fragile-X syndrome showed a well defined pattern of production of interictal epileptiform activity with the lowest values during REM sleep; symptomatic epileptic subjects showed less defined and more variable spike/min diagrams. The spectral analysis of the outline of such diagrams confirmed these differences showing shorter periodicities (80-100 min) in the fragile-X group compared to those of the symptomatic group (160-220 min). Finally, a model with multiple feedback circuits is proposed in order to explain the different patterns observed.

Activity Cycles↗
PubMed1991

The contribution of the large intestine to blood acetate in man.

1. To test the hypothesis that the colon contributes significantly to venous plasma acetate concentrations, experiments were carried out in healthy volunteers and ileostomy patients. 2. Fasting plasma acetate levels were measured in 10 ileostomy patients and compared with those in 21 control subjects. Values in ileostomy patients (21.3 +/- 0.8 mumol/l) were significantly lower than in control subjects (48.0 +/- 4.2 mumol/l). 3. Plasma acetate concentration was estimated in eight healthy volunteers during 108 h of continuous fasting. Acetate concentrations rose significantly from 12 h (43.9 +/- 4.4 mumol/l) to 108 h of starvation (114.0 +/- 15.6 mumol/l) and fell back to normal fasting values on refeeding and another 12 h fast (44.3 +/- 4.7 mumol/l). 4. When colonic fermentation was stimulated after oral ingestion of 10 g of lactulose, the plasma acetate concentration increased significantly (from 44.0 +/- 7.4 to 114.4 +/- 16.2 mumol/l) in seven healthy control subjects. This rise was not affected by concomitant dosage of metronidazole. 5. These data suggest that there are at least two major sources of acetate in man, an endogenous source and the colon which probably becomes more important when fermentation of carbohydrate is occurring.

Acetates↗
PubMed1991

Amino acid metabolism in human subcutaneous adipose tissue in vivo.

1. Arteriovenous differences for alanine, glutamate and glutamine were measured across subcutaneous adipose tissue and forearm muscle in normal subjects. 2. After an overnight fast, adipose tissue showed net production of alanine and glutamine and uptake of glutamate in each of 11 subjects. 3. In seven subjects, adipose tissue blood flow was measured and the measurements were continued for 6 h after eating a mixed meal. The pattern of amino acid metabolism across the adipose tissue was remarkably little disturbed after the meal, except for a short period of apparent uptake of alanine as the concentration of that amino acid rose. 4. The pattern of amino acid metabolism across adipose tissue was qualitatively similar to that across the forearm, although it differed quantitatively in that glutamate uptake was more prominent (compared with glutamine release) in the adipose tissue. 5. The rates of alanine and glutamine release observed suggest that adipose tissue may play a substantial role in the whole-body production of these amino acids.

Adipose Tissue↗
PubMed1991

Energy expenditure and substrate metabolism measured by 24 h whole-body calorimetry in patients receiving cyclic and continuous total parenteral nutrition.

1. Twenty-four hour energy expenditure and its components, i.e. 'basal metabolic rate', activity energy expenditure and diet-induced thermogenesis were measured, using continuous whole-body indirect calorimetry, in patients receiving total parenteral nutrition while in remission from Crohn's disease (weight 51.9 +/- 9.9 kg, body mass index 19.2 +/- 2.0 kg/m2). 2. Total parenteral nutrition was infused continuously over 24 h in four subjects and cyclically, between 22.00 and 10.00 hours, in eight subjects. Twenty-four hour energy expenditure (6.83 +/- 1.10 MJ/24 h) was lower than total energy intake (10.09 +/- 1.63 MJ/24 h), resulting in a positive energy balance (3.26 +/- 1.42 MJ) in all subjects. Repeated measurements of resting energy expenditure in the continuously fed subjects (5.82 +/- 1.11 MJ/24 h) did not change significantly at different times of day (coefficient of variation 2.2-6.6%). In contrast, in cyclically fed subjects, resting energy expenditure was 24.2 +/- 9.0% higher towards the end of the 12 h feeding period than the 'basal metabolic rate', which was measured just before the start of the feeding period. 3. Diet-induced thermogenesis, calculated as the increment in resting energy expenditure above 'basal metabolic rate' over the 24 h period (adjusted for the reduction in energy expenditure during sleep), was found to be 0.60 +/- 0.29 MJ or 6.1 +/- 3.1% of the energy intake. 4. The energy cost of activity (activity energy expenditure) in the continuously fed patients, calculated as the difference between 24 h energy expenditure and the integrated 24 h measurements of resting energy expenditure, was 0.88 +/- 0.53 MJ, i.e. 12.9 +/- 5.9% of the 24 h energy expenditure. 5. The non-protein non-glycerol respiratory quotient exceeded 1.0 for varying periods of time (0.5-17 h) in 11 subjects, indicating net lipogenesis from carbohydrate. 6. The results demonstrate favourable rates of deposition, during intravenous feeding, of both energy and nitrogen over a 24 h period in patients recovering from an episode of Crohn's disease. The efficacy of these commonly used total parenteral nutrition regimens in these patients is related to three features that are absent in normal healthy individuals, namely a low basal metabolic rate, a low activity-related energy expenditure and prolonged periods of lipogenesis from carbohydrate.

Adult↗
PubMed1991

The independent metabolic effects of enflurane anaesthesia and surgery.

The metabolic effects of enflurane anaesthesia (1MAC) in air/oxygen were investigated in six healthy unpremedicated women scheduled for total abdominal hysterectomy (TAH). The changes in acid-base status, CO2 production, and circulating concentration of total protein, albumin and a variety of metabolites (glucose, lactate, glycerol and alanine) were measured before and during a 2-h period of anaesthesia alone, during 1 h of anaesthesia plus surgery, and in the recovery period. The subjects were maintained normothermic (36.5 +/- 0.3 degrees C), and with an arterial SaO2 above 95% throughout the period of study. The circulating concentration of all metabolites changed little as a result of anaesthesia alone, but the glucose and lactate levels rose rapidly after the onset of surgery (P less than 0.05). Plasma albumin and total protein concentration decreased during the study, reaching values that were significantly lower than the pre-anaesthetic values (P less than 0.05). CO2 production decreased by 9% during anaesthesia and surgery, but returned towards preoperative values during recovery. This study provides no evidence of any significant effect of enflurane anaesthesia alone on human intermediary metabolism. Most of the changes in circulating metabolite concentrations observed during and after anaesthesia and surgery are likely to be due to the surgical stress.

Acid-Base Equilibrium↗
PubMed1991

Energy equivalents of CO2 and their importance in assessing energy expenditure when using tracer techniques.

Carbon dioxide production in free living animals and humans can be measured using tracer techniques, but the prediction of energy expenditure also requires an estimate of the energy equivalents of CO2 (energy expended/CO2 produced; EeqCO2). This work is concerned with assessing the variation in EeqCO2 with the use of dietary information, indirect calorimetry, and theoretical concepts. The EeqCO2 for diets (EeqCO2 diet) ingested by 63 individuals living in a Cambridgeshire village, UK, was found to vary by less than 10%. The EeqCO2 diet for different populations varied by greater than 10% and for artificial enteral feeds by approximately 20%. Alcohol increases this variability because it has a particularly high EeqCO2. Variation in the nitrogenous end products of metabolism may also have a substantial effect on the EeqCO2 for a subject (EeqCO2 body), especially when a large proportion of energy expenditure is derived from protein oxidation, as in strict carnivores. Nutrient/energy imbalances such as those associated with growth, hypercaloric feeding, or starvation may also have major effects on EeqCO2 body. It is concluded that the calculation of energy expenditure from CO2 production should not employ a universal value for EeqCO2 body. The value should take into account the physiological and clinical state under investigation. Practical recommendations are suggested.

Adult↗
PubMed1991

Artificial nutrition support for patients in the Cambridge Health District.

This paper describes the results of a one-year prospective survey of patients who received artificial enteral and parenteral nutritional support at home and in the hospitals of the Cambridge Health District. Enteral tube feeding accounted for most of the artificial nutritional support provided both in hospital and in the community. The findings of the study suggest that nutritional support is an important adjunct to the treatment of serious clinical disorders, and that the care of such patients can be improved by the establishment of a multidisciplinary enteral and parenteral nutrition team. Suggestions are made for establishing a structured home nutritional service.

Data Collection↗