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Biomedical subjects

A Fleck

Publications and source records attributed to A Fleck.

At least 37 records · Page 2Linked to original sources
PubMed1989

Clinical and nutritional aspects of changes in acute-phase proteins during inflammation.

1. When assessing the significance of altered plasma protein concentrations the various physiological factors, including posture and hormones which affect the amount and distribution of fluid in the body and the synthesis and catabolism of plasma proteins, must be kept in mind. 2. Although several cytokines, including IL-1 and TNF, are implicated in the acute-phase response, recent evidence is that the synthesis of the major acute-phase proteins (e.g. CRP) is induced by IL-6. 3. The positive acute-phase plasma proteins are useful non-specific indicators of tissue damage. 4. When there is evidence of an acute-phase response (e.g. increased CRP), decreased concentrations of plasma proteins such as albumin, transferrin, retinol-binding protein and pre-albumin cannot be assumed to reflect malnutrition. 5. Plasma albumin concentration can be a good indicator of prognosis.

Acute-Phase Proteins↗
PubMed1988

Observations on the delay in onset of the acute phase protein response.

The early time course of the acute phase protein response (APPR) and mediators involved in its control were investigated in the rat and mouse. After turpentine-induced inflammation in the rat C-reactive protein and fibrinogen increased in concentration peaking at 48 h and 18-24 h, respectively. A 9 h delay prior to elevation of these protein was observed. After injection of endotoxin into mice, a 4-6 h delay was observed prior to any increase in the concentration of the acute phase protein serum amyloid P-component. This delay was shortened to 2 h after injection of leucocytic endogenous mediators (LEM) produced from rabbit peritoneal exudate cells. It is concluded that the delay between the initiating stimulus and the increases in the acute phase proteins is due to some obligatory intermediate steps which lead to the production of the final mediators of the APPR, and that these mediators are present in LEM.

Acute-Phase Reaction↗
PubMed1986

The protein metabolic response to short-term starvation in man.

Plasma protein concentrations, in particular the serum albumin concentration, are often quoted as indicators of nutritional state in surgical patients. Injury also affects the circulating concentrations of these proteins. Twenty students were subjected to a 3-day total fast and the concentration of plasma proteins, generally affected by trauma, determined before and after the fast. The only protein to show any negative response was retinal binding protein which fell by 16% during the starvation period (p < 0.001). Albumin, the protein often used as a nutritional index, demonstrated a significant (p < 0.001) increase during this period. This was not related to changes in the hydration state of the subjects.

Journal Article↗
PubMed1985

Pocket computers: a new aid to nutritional support.

A program has been written to run on a pocket computer (Sharp PC-1500) that can be used at the bedside to predict the nutritional requirements of patients with a wide range of clinical conditions. The predictions of the program showed good correlation with measured values for energy and nitrogen requirements. The program was used, with good results, in the management of over 100 patients needing nutritional support. The calculation of nutritional requirements for each patient individually facilitates more appropriate treatment and may also produce financial savings when compared with administration of a standard feeding regimen to all patients.

Adolescent↗
PubMed1985

Increased vascular permeability: a major cause of hypoalbuminaemia in disease and injury.

The rate of loss of albumin to the tissue spaces (measured as transcapillary escape rate) rose by more than 300% in patients with septic shock, and the average increase within 7 h of cardiac surgery was 100%. The transcapillary escape rate in cachectic cancer patients was twice that of a group of healthy individuals. The rate of loss of albumin to the tissue spaces is normally 5%/h, which is more than 10 times the rates of synthesis and catabolism, and these large rate increases indicate that increased vascular permeability is an important cause of the lowered concentration of albumin commonly seen in acute and chronic disease.

Capillary Permeability↗
PubMed1984

Early plasma protein and mineral changes after surgery: a two stage process.

Sequential changes in albumin, transferrin, alpha 1-acid glycoprotein, C reactive protein, fibrinogen, copper, iron, and zinc in plasma up to 24 h after hysterectomy were measured. No increases in the concentrations of the acute phase proteins alpha 1-acid glycoprotein, C reactive protein, and fibrinogen were observed until 6 h after the skin incision. These increases were preceded by significant falls at 2-4 h, and this was shown also by albumin, transferrin, iron, zinc, and copper. The ratios of iron and zinc to their binding proteins, transferrin and albumin, did not decrease until 4-6 h and their concentrations remained low for at least 24 h. These patterns suggest that at least two mechanisms operate after trauma. The early fall in the concentrations of the proteins in plasma is consistent with a prompt increase in microvascular permeability. The later decrease in binding of the metals iron and zinc to their transport proteins and the increase in concentrations of the acute phase proteins could be initiated by a common mediator.

Adult↗
PubMed1984

Simplified analytical methods for the measurement of the synthesis rate of plasma proteins in vivo by the [14C]carbonate method.

We describe a method for obtaining the specific activity of 14C in urea, essential in the measurement of the synthesis rate of a plasma protein in vivo, which is simpler than the original procedure. The principle is the measurement of 14CO2 and NH4+ separately, after incubation with urease. A simple alteration gives samples of 13CO2 for mass spectrometry. The 'recoveries' of 14C and 13C in urea were invariably between 90 and 96% and the CV was 3%.

Ammonia↗
PubMed1983

The effect of environmental temperature on protein and energy changes following burn injury in the rat.

The metabolic response to a standard burn injury in rats (25% of body surface area) was investigated at environmental temperature 20 degrees C and 30 degrees C. With an intake of 15 g diet (20% w/w protein) per day, burned rats at 20 degrees C were found to be in negative energy balance mainly due to increased insensible (evaporative) losses, and they lost weight. Fat was the main endogenous source of energy, although protein was also catabolised from both carcass and pelt. At 30 degrees C, insensible losses of burned rats were still high, but they had lower sensible (mainly radiative) losses leading to a positive energy balance and a gain in weight. This consisted mainly of carcass water, fat and protein. Urine catecholamines were higher in burned rats at 20 degrees C than at 30 degrees C and correlated with heat loss, urine nitrogen and urine 3-methylhistidine, supporting the hypothesis that catecholamines play a central role in mediating the protein and energy changes following burn injury. For the first 4-6 days, urine nitrogen and 3-methylhistidine excretion increased in rats at 30 degrees C, suggesting that this early part of the metabolic response is obligatory. These findings support the use of raised environmental temperatures to reduce the metabolic response to burns.

Journal Article↗
PubMed1983

Early time course of the acute phase protein response in man.

The rate at which the acute phase protein response occurred after both major and minor surgery was explored. Increases in the plasma concentration of C-reactive protein (CRP), alpha-1-acid glycoprotein (alpha 1 AG) and fibrinogen were not detected until 6-8 h after the initial incision. The peak concentration of CRP occurred at 48 h and that of fibrinogen at 96 h; alpha 1 AG concentrations rose rapidly until 48 h followed by little change until about 120 h. Although there was widespread variation in the concentrations of individual proteins in patients, severity of injury did not seem to have a significant effect on the time course of the change. Plasma cortisol concentration and the total white blood cell count (WBC) reached their peaks before the acute phase proteins, cortisol at 6 h and WBC at 12 h.

C-Reactive Protein↗
PubMed1982

Temperatures used in the determination of enzyme activity in clinical biochemistry laboratories in Britain: results of a survey.

Information on the temperature used in the determination of enzyme activity in clinical biochemistry laboratories in Britain was obtained by circulating a questionnaire to 400 laboratories in Britain. Replies were analysed from 321 laboratories (80%). A large majority of laboratories use 37 degrees C to determine enzyme activity: 99% use this temperature for amylase, 88% for alkaline phosphatase, and 81% for aspartate and alanine amino-transferases. A greater proportion of laboratories with large workloads use 37 degrees C than do those with smaller workloads. The majority of laboratories use equipment with incubation temperatures that are selectable within the laboratory. When there is evidence of advantage in using a particular temperature most laboratories use this temperature. Almost one-quarter of the laboratories replying participate in a local agreement to use 37 degrees to determine enzyme activity. About one-third of laboratories consider it impracticable to change to 30 degrees C, and of those replying to the question on whether they were willing to change to 30 degrees C, 49% indicated that they were not willing to do so.

Alanine Transaminase↗