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Biomedical subjects

G Guarnieri

Publications and source records attributed to G Guarnieri.

At least 19 recordsLinked to original sources

Rheological properties of aqueous Pluronic-alginate systems containing liposomes.

Rheological and erosion studies regarding a liposome-containing polymeric blend that is propaedeutic to its use in paving techniques in tubular organs, such as blood vessels, are reported. Attention is focused on an aqueous polymeric blend composed of Pluronic (PF127) and alginate (Protanal LF 10/60) because both polymers, when dissolved in water at a sufficiently high concentration, are subjected to different structural mechanisms, which are driven by temperature increase and addition of bivalent cations, respectively, and both result in marked viscoelastic and plastic properties. After proving the compatibility between PF127 and alginate, we show that the structural transition temperature of the blend, T(ST), can be properly modulated. In particular, we found that T(ST) for an aqueous solution of pure Pluronic 20% w/w is about 21 degrees C and that even slight reductions in polymer concentration result in considerable T(ST) decrease. The addition of salts or alginate (provided as Na-alginate) provokes a substantial decrease of T(ST) and thus the alginate concentration in the blend should not exceed 1% w/w. In addition, liposomes slow down the structural transition but do not substantially affect the rheological properties of the system in the final state at higher temperatures, thus showing that they can be added to the polymeric blend without significant effects. Finally, erosion tests show that after contact with a source of bivalent cations, the polymeric blend containing PF127 and alginate shows an erosion resistance neatly improved with respect to the simple structured Pluronic system having the same polymer concentration. As a whole, all these results constitute the basis for future potential applications of the considered polymeric blend in tubular organs such as blood vessels.

Alginates↗

Therapeutic potential of hammerhead ribozymes in the treatment of hyper-proliferative diseases.

The limited efficacy of current therapeutic approaches for a number of socially relevant human diseases such as cancer and cardiovascular pathologies, has required the exploration of alternative and more effective therapeutic strategies. In the last two decades, nucleic acid based drugs have emerged as an attractive and novel alternative with great therapeutic potential. Among these molecules, hammerhead ribozymes were the first to be extensively studied and predicted to be of potential practical utility. Hammerhead ribozymes are catalytic RNA molecules capable of inducing the site-specific cleavage of a phosphodiester bond within an RNA molecule. Thus, they can be used to reduce the intracellular level of a specific mRNA coding for a protein which affects cellular metabolism or environment, causing disease. As hammerhead ribozymes can be engineered to reduce the level of virtually any mRNA, they have a very broad applicability. Among the several pathological conditions amenable for a hammerhead ribozyme based therapeutic approach, we focused our attention on pathologies sustained by a dis-regulated and excessive cellular proliferation, being sure to properly demonstrate their usefulness. Trying to be as objective as possible in regard to the feasibility of hammerhead ribozyme employment as therapeutics, a technical section, describing some of the unresolved problems in this field, has been also included. Although some aspects of hammerhead ribozymes as therapeutics can and should be optimized, the encouraging results displayed so far fully justifies further efforts, economic and scientific, to bring them closer to the clinical practice.

Animals↗

Long term prognosis in patients with peripheral arterial disease treated with antiplatelet agents.

OBJECTIVE: To determine the fatal and non-fatal cardiovascular event rate in patients with intermittent claudication treated with antiplatelet agents. METHODS AND DESIGN: Patients with PAD-II stage Fontaine (n=223) and sex and age matched controls (n=446) were followed up from 1974 to 1998. All patients were treated with antiplatelet agents (aspirin, 325 mg once daily or ticlopidine, 250 mg twice daily) and for risk factors, if present. The end points were death for any cause (vascular event, cancer, and others) and non-fatal vascular events (myocardial infarction, ischemic/hemorrhagic stroke, and leg amputation). RESULTS: PAD patients had a significantly higher mortality rate than controls (3.99 vs. 2.53 deaths for 100 patients per year, respectively), cancer (mostly lung, stomach and colon) and vascular mortality accounted for such difference. The incidence of non-fatal vascular events was three times higher in patients than in controls (1.7 vs. 0.56, 100 patients per year, respectively, p<0.05) even considering amputation separately (0.28 vs. 0.00, 100 patients per year, p<0.05). No difference between patients treated with aspirin or ticlopidine could be found in both end points. CONCLUSIONS: Vascular mortality and morbidity, despite the use of antiplatelet agents, are still higher than sex and age matched controls; however, the commonest cause of death is cancer.

Adult↗

Regulation of muscle cathepsin B proteolytic activity in protein-depleted patients with chronic diseases.

BACKGROUND & AIMS: The lysosomal cathepsin system contributes to degrading cellular skeletal muscle proteins in many catabolic diseases. We have assessed the relationships between cathepsin B mRNA levels and the enzyme activity for this protease in the skeletal muscle of acutely ill patients with severe trauma (n=7) and in patients with a variety of chronic disease states (hemodialysis, n=3; nervous anorexia, n=1; type 2 diabetes, n=2; prolonged immobilization, n=1). METHODS: Muscle biopsies were taken from the vastus lateralis muscle in patients and controls to assess tissue levels of cathepsin B mRNA by competitive-quantitative polymerase chain reaction, cathepsin B proteolytic activity and myofibrillar protein content as alkali-soluble protein to DNA ratio (ASP/DNA). In the trauma patients, muscle protein loss was assessed by the arteriovenous balance technique as rate of phenylalanine release from leg muscle. RESULTS: The acute trauma patients exhibited a significant net phenylalanine release from leg muscle (33+/-4 nmol phenylalanine/min/100 ml leg volume) despite a continuous nutritional support. The muscle ASP/DNA ratio was lower (P<0.05) in the patients with chronic diseases (383+/-33) than in groups of healthy controls (554+/-41) or of uncomplicated, moderately obese subjects (525+/-26). Cathepsin B mRNA levels were 6-10 times greater (P<0.05) in the patients with acute trauma or chronic catabolic diseases than in the healthy subjects. Cathepsin B enzymatic activity were 2-3 times greater (P<0.05) in the chronic and acute patients than in the group of uncomplicated, moderately obese subjects. Regression analysis between cathepsin B mRNA and cathepsin B enzymatic activity indicates a significant direct correlation (r=0.84; P<0.05) in the chronic catabolic conditions, but not in the acute trauma patients (r=-0.05). CONCLUSIONS: In skeletal muscle of patients with stable chronic catabolic diseases, cathepsin B activity is directly related to cathepsin B mRNA levels, suggesting that in these patients this enzyme could be mainly regulated at the level of gene transcription.

Analysis of Variance↗

Coagulation indicators in chronic stable effort angina and unstable angina: relationship with acute phase reactants and clinical outcome.

The aim of the study was to evaluate which pattern of coagulation indicators characterizes unstable angina and, particularly, its relationship with short-term prognosis. Forty patients with unstable angina (UA Group) at admission in the intensive care unit, 40 patients with chronic stable effort angina (SEA Group), and 20 age- and sex-matched healthy controls were studied. Blood coagulation indicators were fibrinogen, prothrombin fragment F1 + 2 (F1 + 2), thrombus precursor protein (TpP), and D-dimer. C reactive protein (CRP) and cardiac Troponin I (cTnI) have also been determined and compared. Patients in the UA Group were followed for in-hospital adverse events (sudden death, acute myocardial infarction and angina refractory to medical therapy). CRP, D-dimer and cTnI plasma levels were significantly lower in the SEA Group than in the UA Group; the same trend was found for fibrinogen and F1 + 2 plasma levels, although not statistically significant. The TpP was similar in all groups. The control group showed the lowest levels for all indicators. Within the UA Group, 17 patients developed adverse events during hospitalization; F1 + 2, D-dimer, cTnI and CRP plasma levels were higher in these patients than in those with good outcome. Relative risks for adverse events associated with the highest tertile of D-dimer, cTnI, and CRP plasma levels were 8.4 (95% confidence interval, 1.5-48.9), 6.7 (95% confidence interval, 1.1-38.6) and 5.2 (95% confidence interval, 1.1-25.2), respectively. D-Dimer is significantly increased in patients with unstable angina and, in particular, in those who develop an adverse event.

Acute-Phase Proteins↗

Carnitine metabolism in uremia.

Carnitine is a conditionally essential metabolite that plays a critical role in cell physiology by participating in transesterification reactions and preventing organic acid accumulation. A number of disease states are characterized by carnitine depletion that may lead to metabolic and clinical disturbances. In maintenance hemodialysis, carnitine is lost through dialytic membranes, leading in selected patients to carnitine depletion with a relative increase of the esterified forms. Carnitine supplementation after or during dialysis counteracts such alterations and may be associated with some clinical benefits. Recent meta-analyses of the literature indicate that carnitine supplementation in hemodialysis patients may improve the hematological status (allowing a reduction of the requirement for erythropoietin), the exercise tolerance, the plasma lipid profile, and the intradialytic symptoms. In addition, carnitine supplementation may improve cardiac functions, protein metabolism, and insulin resistance. Carnitine supplementation has been recently approved by the US Food and Drug Administration not only for the treatment, but also for the prevention of carnitine depletion in dialysis patients. Furthermore, clinical guidelines developed by both American and European nephrological societies suggest that a trial with carnitine supplementation could be recommended in selected dialysis patients who do not adequately respond to standard therapy for certain conditions, such as severe and persistent muscle cramps or hypotension during dialysis, lack of energy affecting quality of life, skeletal muscle weakness or myopathy, cardiomyopathy, and anemia of uremia unresponsive to or requiring large doses of erythropoietin.

Carnitine↗

Slower activation of insulin action in upper body obesity.

To determine the influence of body fat distribution on kinetic aspects of insulin action, we have monitored the rate of increase of glucose infusion during 6-hour hyperinsulinemic (40 mU/m2/min) euglycemic clamps in 10 patients with upper body obesity (body mass index [BMI], 41 +/- 3 kg/m2; waist-to-hip ratio [WHR], > 1.00 for men and > 0.85 for women), 12 patients with lower body obesity (BMI, 40 +/- 2 kg/m2; WHR, < 1.00 for men and < 0.85 for women), and 5 control subjects (BMI, < 30 kg/m2; WHR, < 1.00 for men and < 0.85 for women). In all subjects, glucose infusion rate (GIR) to maintain euglycemia increased during the clamp studies to achieve maximal, steady state values after the fourth to fifth hour. During the first 2 hours of clamp, mean GIR (GIR20-120min) (traditional approach to assess insulin sensitivity) was lower (P < 0.05) in the upper body obesity group than in the lower body obesity group (2.12 +/- 0.14 and 3.03 +/- 0.33 mg/kg per min, respectively). In contrast, the maximal steady-state GIR (GIRMAX) (calculated as mean GIR during the sixth hour of clamp) was similar in the upper body and in the lower body obesity groups (4.48 +/- 0.45 and 4.57 +/- 0.36 mg/kg per min, respectively). Control subjects exhibited higher values of both GIR20-120min and GIRMAX (5.57 +/- 0.67 and 7.05 +/- 0.59 mg/kg per min, respectively) than those of both groups of obese patients. The time to reach half-maximal GIR (T1/2) was greater (P < .05) in the upper body obesity (94 +/- 12 min) than that in the lower body obesity (41 +/- 5 min) and in the control group (30 +/- 5 min). In pooled subjects, BMI correlated with GIRMAX (n = 27, R = -.75, P < .001), but not with T1/2 (R = .21). Similarly, whole body percent fat mass, as assessed by bioelectrical impedance analysis, correlated with GIRMAX (n = 16, R = -.79, P < .001), but not with T1/2 (R = .10). In contrast, WHR closely correlated with T1/2 (n = 27, R = .78, P < .001), but not with GIRMAX (R = .11). We conclude that upper body obesity is associated with a slower rate of activation of insulin action on glucose metabolism, whereas total body adiposity selectively affects the maximal, steady-state insulin effect.

Body Constitution↗

Clinical features associated with pre-hospital time delay in acute myocardial infarction.

BACKGROUND: The pre-hospital time delay in acute myocardial infarction (AMI) is still a challenging problem since for many patients there are long intervals between the onset of symptoms and the initiation of therapy. The aim of this study was to verify which, among several clinical variables, are associated with a prolonged pre-hospital time delay. METHODS: Five hundred and twenty-six unselected patients with AMI and consecutively admitted to three coronary care units were enrolled. The pre-hospital time delay was defined as the time interval from the onset of symptoms to admission to the coronary care unit. Clinical variables included: age, gender, body mass index, level of education, alcohol consumption, smoking habits, regular physical activity, history of hypertension, diabetes mellitus, history of coronary artery disease (documented history of angina and/or previous myocardial infarction), chronic atrial fibrillation, Q-wave AMI and off hours onset of symptoms. After univariate analysis, multivariable regression analysis was used. RESULTS: The mean age of the patients was 66.6 +/- 12.1 years and 28.7% were female. The median pre-hospital time interval was 200 min (95% confidence interval 60-1140). For 342 patients the pre-hospital time interval was < or = 6 hours and for 184 patients it was > 6 hours. Those variables which, at univariate analysis, were found to significantly influence the pre-hospital delay were analyzed using a multivariable regression model where the dependent variable was the pre-hospital time interval. Chronic atrial fibrillation (p = 0.010), a history of coronary artery disease (p = 0.017), diabetes (p = 0.016) and age > or = 70 years (p = 0.009) were found to be independently associated with a prolonged prehospital time interval. Similar results were obtained when considering only Q-wave AMI. As expected, the thrombolytic therapy rate was much lower in patients with a longer pre-hospital time delay. CONCLUSIONS: The present study shows that, in case of AMI, the time interval between the onset of symptoms and a patient's arrival to hospital is still far from being optimal. This is especially true for older patients with diabetes, a history of coronary artery disease or chronic atrial fibrillation. Cardiologists should be aware of this problem and should implement adequate educational strategies addressed to those patients at highest risk.

Age Factors↗

Contribution of the ubiquitin-proteasome pathway to overall muscle proteolysis in hypercatabolic patients.

The influence of the gene expression of critical components of the cytoplasmic and lysosomal proteolytic pathways on the rate of protein degradation was evaluated in the leg skeletal muscle of 8 severely traumatized patients. Muscle proteolysis was determined as the intramuscular phenylalanine rate of appearance by L-[ring-2H5]phenylalanine infusion and the leg arteriovenous catheterization technique combined with muscle biopsy. Muscle mRNA levels of UbB polyubiquitin and cathepsin B were determined by reverse transcriptase-competitive polymerase chain reaction and expressed as a percent of the mRNA level of the housekeeping gene glyceraldehyde-3-phosphate dehydrogenase (GAPDH). In the patients, individual values for UbB polyubiquitin mRNA levels directly correlated with the rate of muscle proteolysis (r = .76, P < .05), whereas no correlation (r = .10) was found between cathepsin B mRNA levels and proteolysis. Thus, after trauma, the rate of muscle proteolysis appears to be largely regulated by the ubiquitin-proteasome system at the level of gene transcription.

Adult↗

Coagulation indicators in patients with paroxysmal atrial fibrillation: effects of electric and pharmacologic cardioversion.

The aim of this study was to determine whether paroxysmal atrial fibrillation (PAF) and/or restoration to sinus rhythm with electric or pharmacologic cardioversion induce modifications to the coagulation system. Thirty-five patients with PAF undergoing either electric (n = 11) or pharmacologic (n = 24) cardioversion were studied. Fibrinopeptide A and D-dimer blood samples were taken immediately before and after cardioversion at different intervals. When compared with the control group (n = 70), the precardioversion fibrinopeptide A plasma values were significantly elevated (11.8 vs 2.5 ng/mL). Fibrinopeptide A plasma values were significantly reduced 5 minutes after cardioversion (11.8 vs 5.3 ng/mL) and remained stable throughout the follow-up sequential measurements. D-dimer plasma values were significantly increased (measured at 12 hours and at day 7) in patients who underwent electrical cardioversions only. A positive correlation (R(2) = 0.76) was found between the energy delivered for cardioversion to sinus rhythm and D-dimer plasma values on day 7. In patients with PAF, levels of fibrinopeptide A, an indicator of coagulation activation, are elevated and soon reduced by the restoration of sinus rhythm. Electric, but not pharmacologic, cardioversion induces an early activation of the fibrinolytic system.

Aged↗

Growth hormone decreases muscle glutamine production and stimulates protein synthesis in hypercatabolic patients.

We determined the effects of 24-h recombinant human growth hormone (rhGH) infusion into a femoral artery on leg muscle protein kinetics, amino acid transport, and glutamine metabolism in eight adult hypercatabolic trauma patients. Metabolic pathways were assessed by leg arteriovenous catheterization and muscle biopsies with the use of stable amino acid isotopes. Muscle mRNA levels of selected enzymes were determined by competitive PCR. rhGH infusion significantly accelerated the inward transport rates of phenylalanine and leucine and protein synthesis, whereas the muscle protein degradation rate and cathepsin B and UbB polyubiquitin mRNA levels were not significantly modified by rhGH. rhGH infusion decreased the rate of glutamine de novo synthesis and glutamine precursor availability, total branched-chain amino acid catabolism, and nonprotein glutamate utilization. Thus net glutamine release from muscle into circulation significantly decreased after rhGH administration ( approximately 50%), whereas glutamine synthetase mRNA levels increased after rhGH infusion, possibly to compensate for reduced glutamine precursor availability. We conclude that, after trauma, the anticatabolic action of rhGH is associated with a potentially harmful decrease in muscle glutamine production.

Adult↗

Atherosclerosis and inflammation. Patterns of cytokine regulation in patients with peripheral arterial disease.

Inflammatory phenomena at sites of atherosclerotic plaques are increasingly thought to be major determinants of the progression and clinical outcome of atherosclerotic disease. Therefore, attention is being paid to systemic markers/mediators which may reflect the inflammatory activity in the plaques. This study evaluates the pattern of the main proinflammatory cytokines tumor necrosis factor-alpha (TNFalpha), interleukin-1beta (IL-1beta), and interleukin-6 (IL-6), their soluble receptors/antagonist, and a variety of inflammatory markers, in patients with peripheral arterial disease (PAD). Eight patients with PAD suffering from claudicatio intermittens (CI), eight with critical limb ischemia (CLI) and eight controls (C) were studied. Blood samples were collected at baseline in all groups and. for C and CI, immediately after and 4 h after a 30-min treadmill test. Baseline: no differences in cytokine plasma levels were detected among the three groups. In contrast, soluble receptors of TNF (type I and II) and of IL-6, and IL-1beta receptor antagonist (IL-1ra) were increased in CI and CLI patients, as compared to C. Of note, IL-Ira correlated with the occurrence and stage of the disease in a highly significant proportion of the patients, reaching a predictive value for the disease of P < 0.0001. The opposite trend was observed for the soluble receptor of IL-1beta. Notably, in the patients no alterations could be found in white blood cell counts, expression of CD11c adherence molecule by circulating monocytes or, in vitro. O2- release from zymosan-activated neutrophils. Moreover, plasma levels of platelet activating factor (PAF), of neutrophil elastase and of the acute phase reactants C-reactive protein (CRP) and alpha1-acid glycoprotein were not found to be significantly altered. In contrast, the acute-phase proteins alpha1-antitrypsin (alpha1AT) and haptoglobin (HG) were found to be increased. Effect of treadmill: IL-1beta and TNFalpha remained at baseline levels following exercise, and IL-6 dropped to undetectable levels. Among cytokine antagonists, again the most relevant changes concerned the IL-1ra, which was significantly increased immediately after the treadmill test, both in CI and C, and returned to baseline levels after 4 h. In contrast, soluble TNFalpha, IL-1beta and IL-6 receptors, PAF, and the other markers of leukocyte activation were not found to be altered. Soluble TNFalpha and IL-6 receptors were shown to inhibit the biological effects of their ligands. Similarly, IL-1ra and the acute phase proteins alpha1AT and HG have been reported to exert anti-inflammatory functions. The increased plasma levels of these agents, together with low levels of inflammatory cytokines and other pro-inflammatory mediators such as PAF and alpha1-acid glycoprotein, appear to draw an undescribed picture, so far, of upregulation of a composite systemic anti-inflammatory mechanism in atherosclerotic patients. IL-1ra appears to be a reliable marker of the state of activation of this mechanism. These results may provide a basis for developing new insights into the pathogenesis of the atherosclerotic disease.

Acute-Phase Proteins↗

Slower activation of insulin action in hypertension associated with obesity.

OBJECTIVE: To determine whether kinetic abnormalities in the onset of insulin action contribute to the insulin resistance in obesity-associated hypertension. DESIGN: We monitored the rate of increase in glucose infusion during 6 h of hyperinsulinemic (40 mU/m2 per min) euglycemic clamps in hypertensive and normotensive obese subjects. The two groups of hypertensive (n=9) and normotensive (n=9) subjects were matched for age (48+/-2 versus 45+/-5 years), sex (five males and four females versus four males and five females) and body mass index (42+/-3 versus 40+/-2 kg/m2). RESULTS: In all subjects, the glucose infusion rate required to maintain euglycemia increased progressively during the clamp studies to achieve maximal, steady-state values within the fifth hour. During the first 2 h of the clamp, mean glucose infusion rate, the traditional approach to assessing insulin sensitivity, was lower in the hypertensive than in the normotensive obese patients (2.04+/-0.13 versus 3.29+/-0.41 mg/kg per min, respectively; P < 0.05). In contrast, the maximal steady-state glucose infusion rate, calculated as the mean value during the sixth hour of clamping, was similar in the hypertensive and in the normotensive obese patients (4.48+/-0.43 versus 4.81+/-0.45 mg/kg per min, respectively; NS). The time required to reach the half-maximal glucose infusion rate was greater in the hypertensive than normotensive obese patients (91+/-12 versus 38+/-5 min, respectively; P< 0.05). CONCLUSION: In obesity, hypertension was associated with a slower rate of activation of the insulin effect on glucose metabolism, whereas the maximal steady-state insulin effects were not altered by elevated blood pressure. Thus, the link between obesity and hypertension may be associated with the kinetics of onset of insulin action.

Adult↗

Amino acid and protein therapy in chronic renal failure.

Malnutrition and protein wasting are common features of chronically uremic patients, whether on conservative or dialysis treatment. Optimization of protein-energy intake is difficult because of anorexia, catabolic factors (acidosis, insulin resistance, cytokines, etc.) and intercurrent infections. The use of growth hormone may improve the efficiency of dietary protein utilization. Evidence suggests a small but appreciable effect of very low protein diets on progression of renal insufficiency.

Amino Acids↗

Relationship between whole-body protein turnover and serum creatinine in chronically uremic patients.

To investigate the relationship between decline in renal function and alterations of protein metabolism we determined the rate of whole-body protein turnover in a group of 15 postabsorptive chronically uremic patients (9 males and 6 females) with different levels of serum creatinine concentrations (average 5.7 +/- 0.4 (SE) mg x dl(-1); range 3.3-9.1). Patients' age and body mass index were 53 +/- 4 years (range 26-73) and 24.7 +/- 0.6 kg/m2 (range 20.3-28.7), respectively. Nutritional status (plasma albumin 3.6 +/- 0.4 g x dl[-1]) and acid-base equilibrium (arterial pH 7.38 +/- 0.01) were fairly controlled by therapy. Whole-body leucine rate of appearance (Ra), an index of whole-body protein turnover, was assessed using a stable isotope technique. L-[1-(13)C]leucine was continuously infused and plasma [1-(13)C]alpha-ketoisocaproic acid enrichment was determined in steady-state conditions as a marker of the intracellular leucine enrichment. The average leucine Rawas 2.03 +/- 0.13 micromol x kg(-1) x min(-1) (range 1.29-3.19). Using simple linear regression analysis, the coefficient of correlation between the individual values of serum creatinine concentration and leucine Ra was 0.59 (n = 15; p = 0.02). Leucine Ra did not significantly correlate with blood pH or plasma albumin. In conclusion, we found a positive linear relationship between the values of plasma creatinine concentration and the rate of whole-body protein degradation. This correlation suggests that the progression of renal insufficiency is associated with accelerated rates of turnover of body proteins.

Adult↗

Effects of growth hormone administration on skeletal muscle glutamine metabolism in severely traumatized patients: preliminary report.

We have investigated the effects of 24 h human recombinant growth hormone (hGH) administration on leg muscle glutamine exchange and protein kinetics in severely traumatized patients. Muscle amino acid exchange and protein balance were evaluated using the leg arteriovenous balance technique, whereas changes in skeletal muscle free amino acid concentrations were evaluated in biopsy specimens. hGH infusion decreased phenylalanine release from protein degradation by 56 +/- 14%, and the rate of branched chain amino acid catabolism by 51 +/- 10%. Glutamine release from leg muscle was suppressed by 58 +/- 12%. This latter effect was completely accounted for by a hGH-mediated suppression of glutamine synthesis in skeletal muscle. In conclusion, growth hormone administration in trauma patients may restrain protein and amino acid catabolism in skeletal muscle. However, the growth hormone-mediated suppression of glutamine production we have observed in this study could decrease the systemic availability of this amino acid. During growth hormone treatment, this potential side-effect could be prevented by an exogenous glutamine administration.

Journal Article↗