Avaliação do impacto do tempo de espera para admissão em Unidade de Terapia Intensiva no desfecho clínico do paciente crítico / Assessment of the impact of waiting time until admission in the Intensive Care Unit on the clinical outcome of critical patients

RESUMO: Este estudo tem por base a premissa de que com um maior número de leitos de Unidade de Terapia Intensiva (UTI) disponíveis o tempo de espera para admissão em UTI é menor, o que resulta no melhor desfecho clínico, justifi-cando, portanto, a importância do presente estudo. Objetivo: Avaliar se o tempo de espera no Departamento de Emergência até a admissão em UTI tem influência no desfecho clínico do paciente crítico. Metodologia: Estudo ob-servacional, retrospectivo, do tipo antes e depois, realizado em um hospital público do município de Joinville/SC no ano de 2019. Foram incluídos os dados referentes aos pacientes adultos admitidos na UTI com até 72 horas de es-pera no Departamento de Emergência desde a chegada ao hospital. Comparou-se o último trimestre de 2017 (fase 1), período durante o qual havia 14 leitos de UTI no hospital, e último trimestre de 2018 (fase 2), período durante o qual havia 30 leitos de UTI. Resultados: Analisaram-se 173 prontuários elegíveis de 2017 e 2018. Houve diferen-ça estatisticamente significativa no tempo decorrido na emergência até a admissão em UTI entre 2017 e 2018 (me-diana de 22 vs. 15; p=0,0002). A diferença estatística também foi relevante para a mortalidade em até 24 horas após a admissão em UTI, comparando-se os dois anos em questão (9,61% vs. 2,47%; p=0,04). Não houve diferen-ça estatística significante na mortalidade hospitalar entre 2017 e 2018 (34,6% vs. 35,5%; p=0,57). Também não houve diferença estatisticamente relevante entre os demais parâmetros analisados. Conclusão: Comparando-se 2017 a 2018, percebeu-se que o tempo de espera pelo leito de UTI diminuiu, bem como a mortalidade em até 24h da admissão intensiva. No entanto, isto não se refletiu na mortalidade hospitalar. (AU)

ABSTRACT: The premise that underpins this study is that the more Intensive Care Unit (ICU) beds available, the shorter the waiting time for ICU admission, resulting in better clinical outcomes, which justifies the relevance of this study. Objective: Assess if the waiting time in the Emergency Room until ICU admission influences on the clinical outcome of critical patients. Methods: An observational longitudinal retrospective study performed in a public hospital in Joinville/SC in 2019. This study analyzed data from patients admitted to the ICU with up to 72h of waiting time in the Emergency Room. It compares Q4'2017 (phase 1), when there were 14 ICU beds in the hospital vs. Q4'2018 (phase 2), when there were 30 ICU beds. Results: 173 medical records were analyzed in 2017-2018. There was a statistically significant difference in the time for ICU admission between 2017 and 2018 (median 22h vs. 15h; p=0.0002). There was also a statistically significant difference for mortality rates up to 24h of admission (9.61% vs. 2.47%; p=0.04). There was no statistically significant difference for hospital mortality rates (34.6% vs. 35.5%; p=0.57). There was also no statistically significant difference between the other parameters analyzed. Conclusion:Comparing 2017 and 2018, waiting time for an ICU bed was shorter in 2018, and the mortality rates up to 24 hours of ICU admission were lower. However, waiting time in the Emergency Room until ICU admission did not show as-sociation with hospital mortality rates. (AU)

Fibrinogen kinetics and protein turnover in obese non-diabetic males: effects of insulin.

BACKGROUND: Although hyperfibrinogenemia and insulin resistance are common in obesity and diabetes mellitus, the impact of obesity per se on fibrinogen turnover and the insulin effects on fibrinogen and protein kinetics is unknown. METHODS: We measured fibrinogen and albumin fractional (FSR) and absolute (ASR) synthesis rates, as well as protein turnover, in non-diabetic, obese and in control male subjects both before and following an euglycemic, euaminoacidemic, hyperinsulinemic clamp, using L-[(2)H(3)]-Leucine isotope infusion. RESULTS: In the obese, basal fibrinogen concentrations was approximately 25% greater (p < 0.035), and fibrinogen pool approximately 45% greater (p < 0.005), than in controls. Both FSR and ASR of fibrinogen were similar to control values. With hyperinsulinemia, although fibrinogen FSR and ASR were not significantly modified with respect to baseline in either group, fibrinogen ASR resulted to be approximately 50% greater in the obese than in controls (p < 0.015). Hyperinsulinemia equally stimulated albumin synthesis and suppressed leucine appearance from endogenous proteolysis in both groups. Amino acid clearance was also similar. In the obese, the insulin-mediated glucose disposal was approximately 50% lower (p < 0.03) than in controls, and it was inversely correlated with fibrinogen ASR during the clamp in both groups (r = - 0.58). CONCLUSIONS: In obese, non-diabetic males, post absorptive fibrinogen production is normal. Whole-body amino acid disposal, basal and insulin-responsive protein degradation, and albumin synthesis are also normal. However, the greater fibrinogen ASR in the obese with hyperinsulinemia, and the inverse relationship between insulin sensitivity and clamp fibrinogen production, suggest a role for hyperinsulinemia and/or insulin resistance on fibrinogen production in obesity.

Hepatic lipid metabolism and non-alcoholic fatty liver disease.

Non-alcoholic fatty liver disease (NAFLD) is an increasingly recognized pathology with a high prevalence and a possible evolution to its inflammatory counterpart (non-alcoholic steatohepatitis, or NASH). The pathophysiology of NAFLD and NASH has many links with the metabolic syndrome, sharing a causative factor in insulin resistance. According to a two-hit hypothesis, increased intrahepatic triglyceride accumulation (due to increased synthesis, decreased export, or both) is followed by a second step (or "hit"), which may lead to NASH. The latter likely involves oxidative stress, cytochrome P450 activation, lipid peroxidation, increased inflammatory cytokine production, activation of hepatic stellate cells and apoptosis. However, both "hits" may be caused by the same factors. The aim of this article is to overview the biochemical steps of fat regulation in the liver and the alterations occurring in the pathogenesis of NAFLD and NASH.

Fibrinogen kinetics and protein turnover in hypertension: Effects of insulin.

BACKGROUND AND AIM: Hyperfibrinogenemia, a cardiovascular risk factor, is frequent in hypertension and largely unexplained. In this study, we measured fibrinogen production and whole-body protein turnover under both basal and hyperinsulinemic states, in hypertensive [H] and control [C] subjects, using a leucine stable isotope tracer and precursor-product relationships. METHODS AND RESULTS: Since hypertension is often a feature of the "metabolic", insulin resistance syndrome, which in turn affects both fibrinogen kinetics and whole-body protein turnover, we selected hypertensive subjects without the metabolic syndrome. Following basal measurements, an euglycemic, approximately euaminoacidemic, hyperinsulinemic clamp was performed, with plasma insulin raised to 700-900 pmol/L. In H, rates of the fractional and absolute synthesis (FSR and ASR, respectively) of fibrinogen were 30%-40% greater (p<0.05 or less) than in C in both states, whereas leucine turnover was normal. Hyperinsulinemia did not modify fibrinogen synthesis in either group with respect to baseline, whereas it suppressed leucine appearance from endogenous proteolysis by approximately 40% to same extent in both groups. Amino acid clearance was similar in both the H and C subjects. In H, the insulin-mediated glucose disposal (M) was approximately 25% lower, (although insignificantly) than in controls, showing no overall insulin resistance. There was an inverse correlation between M and fibrinogen FSR during the clamp. CONCLUSIONS: In essential hypertension fibrinogen production is increased, is not further stimulated by insulin, and is inversely related to insulin sensitivity at high-physiological insulin concentrations. Amino acid disposal and basal as well as insulin-responsive protein degradation rates are instead normal.

Rapid, simple and effective technical procedure for the regeneration of IgG and HSA affinity columns for proteomic analysis.

In plasma and serum, the presence of high-abundance proteins can overwhelm the signals of low-abundance proteins, which then become undetectable either by two-dimensional gels or chromatographic techniques. Therefore, depletion of abundant proteins is a prerequisite to detect low-abundance components. Furthermore, the regeneration of pre-purification tools could be money-saving. We applied an affinity chromatography kit to remove albumin and the immunoglobulin chains from plasma and propose a simple and effective technical procedure for the regeneration of these affinity columns.

Diabetic nephropathy is associated with increased albumin and fibrinogen production in patients with type 2 diabetes.

AIMS/HYPOTHESIS: Hyperfibrinogenaemia and albuminuria are cardiovascular risk factors, often coexisting in diabetic and non-diabetic people. Albuminuria in turn is associated with a compensatory albumin overproduction in non-diabetic patients. It is not known whether the presence of albuminuria in patients with type 2 diabetes mellitus is associated with greater albumin and fibrinogen production rates than in normoalbuminuric patients. SUBJECTS, MATERIALS, AND METHODS: Using leucine isotope methods, we measured fractional and absolute synthesis rates (FSR, ASR) of albumin and fibrinogen in post-absorptive type 2 diabetic patients with either normal (n=11) or increased (n=10) urinary albumin excretion. RESULTS: In albuminuric patients, albumin FSR (16.2+/-1.5%/day) and ASR (20.5+/-1.9 g/day) were greater (p<0.02 and p<0.05, respectively) than in normoalbuminuric patients (FSR=11.5+/-1.1%/day; ASR=15.7+/-1.2 g/day). Fibrinogen FSR was similar between patients with normal and increased albumin excretion, but concentration, the circulating pool and ASR of fibrinogen were 40 to 50% greater (p<0.035) in patients with albuminuria. Albuminuria was positively correlated with albumin ASR, with fibrinogen concentration, the fibrinogen pool and ASR, whereas albumin synthesis was inversely correlated with calculated oncotic pressure. CONCLUSIONS/INTERPRETATION: Synthesis of albumin and fibrinogen is upregulated in type 2 diabetic patients with increased urinary albumin excretion. Albuminuria is associated with enhanced fibrinogen and albumin synthesis.

Impairment of albumin and whole body postprandial protein synthesis in compensated liver cirrhosis.

To investigate the anabolic effects of feeding in cirrhosis, we measured albumin fractional synthesis rate (FSR) and whole body protein synthesis in six nondiabetic patients with stable liver cirrhosis (three in the Child-Pugh classification Class A, three in Class B) and in seven normal control subjects, before and after administration of a 4-h mixed meal. Leucine tracer precursor-product relationships and whole body kinetics were employed at steady state. Basal levels of postabsorptive albumin concentration and FSR, whole body leucine rate of appearance, oxidation, and nonoxidative leucine disposal (NOLD, approximately equal to protein synthesis) were similar in the two groups. However, after the meal, in the patients neither albumin FSR (from 8.5 +/- 1.5 to 8.8 +/- 1.8 %/day) nor NOLD (from 1.69 +/- 0.22 to 1.55 +/- 0.26 micromol x kg(-1) x min(-1)) changed (P = nonsignificant vs. basal), whereas they increased in control subjects (albumin FSR: from 10.9 +/- 1.5 to 15.9 +/- 1.9 %/day, P < 0.002; NOLD: from 1.80 +/- 0.14 to 2.10 +/- 0.19 micromol x kg(-1) x min(-1), P = 0.032). Thus mixed meal ingestion did not stimulate either albumin FSR or whole body protein synthesis in compensated liver cirrhosis. The mechanism(s) maintaining normoalbuminemia at this disease stage need to be further investigated.

Insulin infusion normalizes fasting and post-prandial albumin and fibrinogen synthesis in Type 1 diabetes mellitus.

AIMS: The effect of metabolic control on hepatic synthesis of plasma proteins in Type 1 diabetes mellitus (T1DM), in the post-absorptive and post-prandial state, is not known. METHODS: We measured fractional synthetic rates (FSR) of albumin and fibrinogen in six insulin-infused T1DM patients and in five to nine control subjects, before and for approx. 4 h after a mixed liquid meal. Phenylalanine tracer precursor/product relationships and steady-state conditions were used. In the post-absorptive state, patients were studied in near euglycaemic conditions after an overnight intravenous insulin infusion. During the meal (approx. 11 kcal/kg), the insulin infusion rate was increased to maintain plasma glucose concentrations below approx. 10 mmol/l. RESULTS: Post-absorptive FSR of albumin (5.7 +/- 0.6%/day) and fibrinogen (11.3 +/- 0.6%/day) in T1DM were similar to control values (6.4 +/- 0.9 and 13.1 +/- 1.1, respectively). After the meal, albumin FSR increased (P = 0.0032 by anova) in both groups (T1DM, to 14.4 +/- 2.7%/day; controls, to 18.2 +/- 3.7%/day). Fibrinogen FSR also increased (P = 0.0048 by anova) in both the T1DM (to 18.2 +/- 2.6) and the control subjects (to 27.3 +/- 6.2). There was no difference between T1DM and control subjects in the post-prandial FSR of both proteins. CONCLUSIONS: Albumin and fibrinogen FSR in T1DM can be maintained within near-normal ranges by insulin infusion under post-absorptive and post-prandial conditions.

Plasma protein synthesis in patients with low-grade nephrotic proteinuria.

Overt nephrotic syndrome is characterized by albumin and fibrinogen hyperproduction and reduced very low density lipoprotein apolipoprotein B-100 (VLDL apoB-100) clearance. Whether similar changes also occur in low-grade proteinuria is not known. Thus we measured albumin, fibrinogen, and VLDL apoB-100 kinetics in six patients with modest proteinuria and normal creatinine clearance (P) and in ten control subjects (C) by leucine tracer infusion and precursor-product relationships. In P, plasma albumin concentration was decreased (P < 0.003), whereas concentrations of fibrinogen and VLDL apoB-100 were increased (P < 0.001). In P, albumin fractional secretion rate (FSR) was increased (P < 0.01), fibrinogen FSR was normal, and VLDL apoB-100 FSR was decreased (P < 0.03). As a result, in P, absolute secretion rates (ASR) of albumin and fibrinogen were increased (P < 0.03), whereas VLDL apoB-100 ASR was normal. Albumin FSR was inversely correlated to oncotic pressure in P but not in C. These findings suggest that low-grade nephrotic proteinuria is characterized by simultaneous multiple alterations in turnover rates of albumin, fibrinogen, and VLDL apoB-100. Their pathogenesis, however, appears to be multifactorial.

Glucose kinetics and splanchnic uptake following mixed meal ingestion in cirrhotic-diabetic subjects.

Although glucose intolerance and/or overt diabetes are common in cirrhotic subjects, the mechanism(s) that lead to post-prandial hyperglycemia in cirrhosis are not entirely known. To this aim, we measured whole-body rates of glucose appearance (Ra) and of disappearance (Rd) in cirrhotic-diabetic subjects and in controls, before and following a 4-hr administration of a mixed meal. In the post-prandial phase, endogenous and dietary glucose Ra, as well as first-pass splanchnic uptake of dietary glucose, were measured using a double (ie oral and intravenous) glucose tracer technique. In the fasting state, the cirrhotic patients were hyperglycemic (12.0 +/- 1.4 vs 4.4 +/- 0.2 mmol/l in controls, p < 0.001), had a higher glucose Ra (17.0 +/- 2.7 vs 10.2 +/- 0.5 micromol x kg(-1) x min(-1), p < 0.05) and a lower clearance rate (1.51 +/- 0.19 vs 2.32 +/- 0.06 ml x kg x min, p < 0.02). Following the meal, plasma glucose increased to greater values (p < 0.002) in the patients (to 16.8 +/- 2 mmol/l, mean values of the last 40 min) than in the controls (to 7.2 +/- 0.4 mmol/l). Insulin increased in both groups but it was 35% lower (p > 0.05) in the patients. Post-prandial total glucose Ra (cirrhotics: 21.3 +/- 2.6; controls: 19.2 +/- 1.4 pmol x kg(-1) x min(-1)), endogenous Ra (cirrhotics: 7.3 +/- 1.5; controls: 7.0 +/- 1.3 micromol x kg(-1) x min(-1)) and first-pass splanchnic uptake of dietary glucose (cirrhotics: 9.8 +/- 2.6; controls: 11.5 +/- 1.6 micromol x kg x min(-1)), were not different between the 2 groups, whereas glucose clearance remained lower (p<0.001) in the patients (1.31 +/- 0.25 ml x kg(-1) x min)-1)) than in the controls (2.72 +/- 0.26). These data demonstrate that, in cirrhotic-diabetic patients, post-pran-dial hyperglycemia is not due to a reduced extraction of dietary glucose nor to an increased endogenous production, but rather to a defect in peripheral glucose clearance, secondary to either insulin-resistance and/or relative insulin deficiency.

Role of insulin in age-related changes in macronutrient metabolism.

Age is associated with an increase in body fat mass and a decrease of protein mass. As body substrate turnover is under insulin control, defects in insulin secretion and/or action may in part account for these changes. As regards secretion, current evidence suggest that no clear defect in insulin secretion is found in the aged. The wide spectrum of glucose tolerance of the elderly may be associated with different patterns of insulin secretion. Insulin sensitivity to glucose metabolism is more or less normal in the aged, despite subtle delays in the onset of its action. Normalization of the data by either body weight or lean body mass is important in defining the insulin sensitivity of the elderly. Increased rates of free fatty acid (FFA) flux and oxidation rates have been found in healthy elderly subjects, both when post-absorptive and during hyperinsulinemia. These differences however disappeared following normalization by fat mass, suggesting that FFA kinetics reflect the established changes in fat mass. Thus, the mechanism(s) leading to an increase in the fat mass in elderly cannot simply be derived from studies of fat kinetics. The operation of the Randle cycle (ie, inverse relationships between fat and glucose oxidation) in the elderly has also been suggested. Finally, the insulin effects on whole-body amino acid and protein metabolism do not seem to be impaired in the aged. However, in the human muscle a decreased synthesis of contractile as well as mitochondrial proteins was found, in association with decreased specific gene expression. The degree of physical activity probably interacts with these changes, possibly playing a causative role. The possible interaction between insulin and exercise in the maintenance of muscle mass in the elderly needs to be studied further.

Increased fibrinogen production in type 2 diabetic patients without detectable vascular complications: correlation with plasma glucagon concentrations.

Fibrinogen is a strong cardiovascular risk factor in the general population, and increased fibrinogen plasma concentrations have been reported in type 2 diabetic patients. However, the mechanisms leading to hyperfibrinogenemia in type 2 diabetes are not known. It is also not known whether possible alterations of fibrinogen turnover may precede clinical diabetic micro- and macrovascular complications and therefore potentially contribute to their onset. To address these questions, fibrinogen production was determined in six male type 2 diabetic patients without detectable micro- and macrovascular complications (age, 45 +/- 4 yr; body mass index, 27 +/- 0.9 kg/m2) and in seven nondiabetic matched controls using leucine isotope precursor-product relationships. Plasma glucose (P < 0.001), insulin (P < 0.05), and glucagon concentrations (P < 0.01) were increased in the patients. Diabetic patients also had increased plasma fibrinogen concentration (+ approximately 50%; P < 0.01) and pool (+ approximately 40%; P < 0.01) as well as fractional (+ approximately 35%; P = 0.08) and absolute (+ approximately 100%; P < 0.01) synthetic rates. The plasma glucagon concentration was positively related (P < 0.005 or less) to the fibrinogen concentration as well as to fractional and absolute synthetic rates. Thus, fibrinogen production is markedly enhanced, and this alteration is likely to determine the observed hyperfibrinogenemia in type 2 diabetic patients. Hyperglucagonemia may contribute to the increased fibrinogen production. These findings in normoalbuminuric patients without clinical complications support the hypothesis that increased fibrinogen production and plasma concentrations may precede and possibly contribute to the onset of clinical cardiovascular complications in type 2 diabetes.

Changes in protein, carbohydrate, and fat metabolism with aging: possible role of insulin.

Age is associated with modifications of body composition, i.e., an increase in body fat mass and a decrease in protein mass. Because insulin controls substrate disposal and production, these changes could theoretically be related to changes in either insulin action or secretion on the various substrates. On the basis of available evidence, insulin action on whole-body amino acid and protein metabolism seems not to be impaired in the aged. Decreased synthesis of contractile and mitochondrial proteins in muscle, associated with decreased gene expression, was described in humans. Decreased physical activity apparently represents an important factor responsible for decreased muscle protein synthesis and mass in the elderly. Exercise in the elderly may acutely revert these changes, although its chronic effects are still uncertain. In addition, the possible interaction between insulin and exercise in the maintenance of muscle mass needs to be specifically investigated in aged people. Higher free fatty acid (FFA) absolute flux and oxidation rates were observed in healthy elderly subjects in both the fasting state and following hyperinsulinemia, but not when normalized over fat mass. This suggests that FFA kinetics reflect the established changes in fat mass. Insulin sensitivity on glucose metabolism is usually normal in the aged, despite subtle impairments in insulin secretion, hepatic uptake, and onset of action. Finally, data support the operation of the Randle cycle (i.e., inverse relationships between fat and glucose oxidation) in the elderly.

Interorgan amino acid exchange.

This review is concerned with the status of our current research related to the exchange of amino acids across organs. Accumulation of knowledge regarding how amino acid pools are maintained within the body remains a work in progress. In recent years, the use of organ balance measurement techniques in combination with isotopic tracers has much increased our understanding of the role of the kidney and splanchnic organs in amino acid metabolism, and in kidney and liver gluconeogenesis from amino acids. An interorgan cooperation between the kidney and splanchnic organs for leucine-ketoisocaproate metabolism has also been demonstrated.

Phenylalanine hydroxylation across the kidney in humans rapid communication.

UNLABELLED: Phenylalanine hydroxylation across the kidney in humans. BACKGROUND: Although phenylalanine hydroxylase activity is detectable in in vitro renal tissue preparations, no data on in vivo phenylalanine hydroxylation across the human kidney, as well as on its possible contribution to whole-body hydroxylation, currently exist. METHODS: To this aim, we have measured whole-body, renal, and splanchnic phenylalanine hydroxylation to tyrosine, as well as phenylalanine and tyrosine rates of appearance (Ra) and disposal (Rd), in postabsorptive subjects by means of renal and splanchnic arteriovenous catheterization combined with phenylalanine and tyrosine isotope infusions. RESULTS: In the kidney, a relevant phenylalanine hydroxylation activity was detected (3.51 +/- 0.97 micromol/min x 1.73 m2 of body surface), whereas it was 2.48 +/- 1. 35 micromol/min x 1.73 m2 across the splanchnic area. These two sites together accounted for virtually the entire whole-body phenylalanine hydroxylation. Renal production of tyrosine from phenylalanine hydroxylation accounted for approximately 13% of whole-body tyrosine Ra, whereas renal total tyrosine Ra accounted for approximately 34% of whole-body tyrosine Ra. In the splanchnic area, these figures were approximately 9 and 40%, respectively. Hydroxylation accounted for approximately 70% of phenylalanine Rd in the kidney, as opposed to approximately 8% in the splanchnic area. CONCLUSIONS: These data indicate that hydroxylation represents the major route of phenylalanine disposal within the kidney. The kidney and the splanchnic bed together account for all of the whole-body phenylalanine hydroxylation. These data also provide a further explanation for the reduced tyrosine pools occurring in uremia.

Differences in estimates of forearm protein synthesis between leucine and phenylalanine tracers following unbalanced amino acid infusion.

We compared the leucine (Leu) and phenylalanine (Phe) tracer-determined response of forearm protein synthesis (PS) before and after stimulation of protein anabolism by intravenous infusion of Leu-enriched, Phe-deficient amino acids and insulin (increased to approximately 100 microU/mL) with the euglycemic clamp. Six healthy subjects received primed-constant infusions of L-[ring-2H5]-Phe and L-[1-(14)C]-Leu, and steady-state forearm Phe and Leu kinetics were determined. Following the combined infusion, the arterial Leu concentration increased approximately 70% (P < .001), whereas Phe decreased about 15% (P < .01). Forearm PS and net balance (NB) increased (P < .05 or less v basal) using both amino acid tracers. However, the relative increments observed with the Leu tracer were more than 75% larger (P < .05 or less) than those observed with the Phe tracer, even when the data were corrected for the standard relative abundance of these two amino acids in forearm protein(s). Thus, the calculated changes of forearm PS and NB in response to an unbalanced amino acid infusion with hyperinsulinemia were affected by the plasma level of leucine and phenylalanine, whose tracers were used to estimate forearm protein turnover. Since these two essential amino acids share the same transport system, a competition at this level cannot be excluded.

Effects of branched-chain-enriched amino acids and insulin on forearm leucine kinetics.

Although amino acid mixtures enriched in branched-chain amino acids (BCAA) and deficient in aromatic amino acids (AAA) are often used together with insulin and glucose in clinical nutrition, their physiological effects on muscle protein anabolism are not known. To this aim, we studied forearm leucine kinetics in post-absorptive volunteers, before and after the systemic infusion of BCAA-enriched, AAA-deficient amino acids along with insulin and the euglycaemic clamp. The results were compared with the effects of insulin infusion alone. A compartmental leucine forearm model was employed at steady state. Hyperaminoacidaemia with hyperinsulinaemia (to approximately 80-100 micro-units/ml) increased the leucine plasma concentration (+70%; P<0.001), inflow into the forearm cell (+150%; P<0.01), disposal into protein synthesis (+100%; P<0.01), net intracellular retention (P<0.01), net forearm balance (by approximately 6-fold; P<0.01) and net deamination to alpha-ketoisocaproate (4-methyl-2-oxopentanoate) (+9%; P<0.05). Leucine release from forearm proteolysis and outflow from the forearm cell were unchanged. In contrast, hyperinsulinaemia alone decreased plasma leucine concentrations (-35%; P<0.001) and leucine inflow (-20%; P<0.05) and outflow (-30%; P<0.01) into and out of forearm cell(s), it increased net intracellular leucine retention (P<0.03), and it did not change leucine release from forearm proteolysis (-20%; P=0.138), net leucine deamination to alpha-ketoisocaproate, leucine disposal into protein synthesis or net forearm protein balance. By considering all data together, leucine disposal into protein synthesis was directly correlated with leucine inflow into the cell (r=0.71; P<0.0001). These data indicate that the infusion of BCAA-enriched, AAA-deficient amino acids along with insulin is capable of stimulating forearm (i.e. muscle) protein anabolism in normal volunteers by enhancing intracellular leucine transport and protein synthesis. These effects are probably due to hyperaminoacidaemia and/or its interaction with hyperinsulinaemia, since they were not observed under conditions of hyperinsulinaemia alone.