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Biomedical subjects

G Bonetti

Publications and source records attributed to G Bonetti.

47 records · Page 3Linked to original sources
PubMed1985

Parenteral nutrition of injured patients: Effect of manipulation of aminoacid infusion (increasing branched chain while decreasing aromatic and sulphurated aminoacids).

Sixteen critically ill injured patients received parenteral nutrition providing nitrogen (0.34 g kg(-1) day(-1)) and glucose (32 kcal kg(-1) day(-1)) for 5 days. They were randomly divided into two groups with respect to aminoacid supply: an essential aminoacid solution vs the same solution enriched in branched chain amino acid (BCAA) content and decreased in phenylalanine and methionine content (mean BCAA intake, 0.55 vs 0.69 g kg(-1) day(-1)). Basal values of nitrogen metabolism without treatment showed no difference between the two groups. Nitrogen losses and 3 methylhistidine (3-MEH) excretion were elevated; the plasma aminoacid pattern was altered by the trauma and except for phenylalanine, aspartate and glutamate, plasma aminoacid concentrations were decreased below normal values. Net muscular aminoacid output was demonstrated by femoral arterio-venous (av) differences that were all negative except for glutamate and citrulline TPN with both solutions improved the nitrogen balance and reduced the negative aminoacid balance across the leg. Adjusting a TPN regimen to increase the BCAA content without altering the total nitrogen infused, had no effect on overall nitrogen balance, but exerted a beneficial effect on body protein catabolism, as assessed by the urinary 3-MEH excretion rate, and a transient improvement in the aminoacid balance across the leg at the peak of the infusion. The short-lived effect of BCAA suggest a metabolic effect of these aminoacids which deserves further study.

Journal Article↗
PubMed1982

Vitamin C in normal human mononuclear and polymorphonuclear leukocytes.

Human peripheral leukocytes from healthy donors have been isolated by means of a suitable separation method to obtain a high yield of lymphocytes and granulocytes with a very low contamination of platelets and red blood cells. Mononuclear cells so purified contain more than double amounts of vitamin C than polymorphonuclear cells. The difference between lymphocytes and granulocytes content also tends to be larger at increasing vitamin concentrations in total leukocytes. A higher level of vitamin C is displayed by the mononuclear cells obtained from women in respect to men, while no significant difference is found in the polymorphonuclear cells.

Adolescent↗
PubMed1979

[Transplantation of the kidney in the rat. I. Problems of surgical technic].

Is described a technique for transplanting rat kidneys. The technique involves suture of vessels of less than 1 mm in diameter with microsurgical techniques. Were used adult male rats of wistar strain. The kidney is perfused with 250 cc of ringer lactate, heparin 10.000 U.I., solumedrol 1 g novocain 150 mg. The results were very good.

Animals↗
PubMedDate not supplied

Influence of total parenteral nutrition on protein metabolism following acute injury: assessment by urinary 3-methylhistidine excretion and nitrogen balance.

The use of total parenteral nutrition after acute injury, either surgical or accidental, is widely accepted for its important benefits, although it is not yet completely understood whether a reduction of body protein catabolism can be effectively achieved. We applied total parenteral nutrition to 14 critically ill patients after either trauma or major surgery. Their daily nitrogen balance, urinary 3-methylhistidine and creatinine excretion, and molar 3-methylhistidine/creatinine ratio, during initial 24-hr fasting period, were respectively -0.19 +/- 0.01 (SEM) g kg-1, 5.46 +/- 0.47 mumol kg-1, 27 +/- 4 mg kg-1, and 0.030 +/- 0.005. Daily nonprotein calorie intake of 31.11 +/- 0.58 kcal kg-1, as glucose, and administration of nitrogen 0.350 +/- 0.004 g kg-1, as 10% crystalline L-aminoacids solution, and insulin 1 IU every 5.03 +/- 0.14 g of glucose, resulted in progressive decline of urinary 3-methylhistidine (4.21 +/- 0.43 mumol kg-1, p less than 0.001), creatinine (22 +/- 2 mg kg-1, NS), and their molar ratio (0.022 +/- 0.002, NS). Mean nitrogen balance resulted in 0.032 +/- 0.008 g kg-1. Since urinary 3-methylhistidine role as a marker of protein catabolism is well established, its decrease under total parenteral nutrition together with greatly improved nitrogen balance, demonstrates that our treatment can effectively quench protein catabolism, meanwhile enhancing protein synthesis.

Adult↗
PubMedDate not supplied

The sensitivity of cardiac markers: an evidence-based approach.

The aim of this study was to determine whether, using an evidence-based approach, the results of the papers found in the literature are valid and sufficiently scientifically rigorous to be used to definitely address the problem of cardiac marker sensitivity in detection of acute myocardial infarction. In particular, the diagnostic sensitivities of myoglobin, creatine kinase (CK)-MB isoenzyme, determined as mass concentration, CK-MB isoforms, and of the two cardiac troponins, troponin I and troponin T, were reviewed using a priori formulated inclusion/exclusion criteria for judging the eligibility of studies to be included in the analysis. A clear final message derived from this systematic analysis is the unacceptably poor diagnostic sensitivity of all evaluated markers at patient admission, with substantial failure rate to rule out myocardial infarction at this time. Myoglobin is at present the most sensitive of the markers studied for excluding early AMI with an optimum timing of sampling at patient presentation and approximately 4 h later. However, this marker cannot be used by itself as a proportion of patients admitted to the hospital with a late infarction could be missed. The early rate of rise of CK-MB mass and troponin T is similar. Maximum sensitivity of these two parameters is achieved by the analysis of a second sample 6 to 12 h after admission. Additional larger studies are needed to address the question which troponin shows earlier release after myocardial damage, and to clarify the role of CK-MB isoforms as a possible early marker of myocardial infarction.

Biomarkers↗
PubMedDate not supplied

[Energy metabolism and metabolite flow from muscle tissue during TPN of trauma patients].

AIM: We evaluated muscle-visceral interorgan flux of substrates in 8 critically ill patients in the flow phase after injury. SETTING: This study was conducted on critically ill patients admitted in ICU. PATIENTS: 8 patients were studied immediately after injury. RESULTS: We measured leg flux for oxygen, amino acids, glucose, lactate pyruvate, keton bodies, free fatty acids (FFA), free and total carnitine, and whole body oxygen consumption, nitrogen (N) balance and 3-methyl hystidine (3MEH) excretion during fasting and the second day of metabolic treatment (10.7 +/- 0.06 g x N x m-2 e 1035.5 +/- 3.9 kcal x m-2 x die). During fast the leg shows a net release of N, pyruvate, FFA and free carnitine while glucose, lactate and keton bodies fluxes are not different from zero. The energy balance of the leg is markedly negative (substrate for 79 kcal x m-2 burned for leg energy requirement and 347 kcal x m-2 released as a such). Assuming the body muscle tissue 4.5 times the leg tissue and knowing whole body energy balance, we were able to assess that the non muscular (visceral) part of the body resulted in a consistently positive energy balance. The metabolic treatment is able to match the energy expenditure and the substrate efflux of the leg (and the whole body muscle tissue). In fact the efflux of amino acids and FFA is reduced pyruvate blunted while glucose is remarkably taken up (the uptake of the whole muscle tissue accounted for 72% of the daily load). At the same time, the treatment blunts leg free carnitine and reduces body 3MEH output. Moreover, the caloric balance of the non muscular part of the body remains positive even if the qualiquantitative uptake of substrates is different from fasting. CONCLUSION: Substrates for energy requirements of visceral tissue came from muscular tissue. The metabolic treatment is able to modulate this process.

Energy Metabolism↗