Papers by Giuseppe Benedetti
The American Journal of Clinical Nutrition, 1998
Several hypotheses have been proposed to explain the nutritional deficiencies seen in Crohn disea... more Several hypotheses have been proposed to explain the nutritional deficiencies seen in Crohn disease patients, including inadequate food intake, decreased assimilation and increased loss of nutrients, and increased energy expenditure. To assess the effect of steroid therapy on body composition, energy expenditure, and fuel selection in Crohn disease, we compared 12 patients (6 men and 6 women) with biopsy-proven ileal Crohn disease with 11 healthy volunteers (6 men and 5 women). Five patients [Crohn's disease activity index (CDAI) = 98.4 ± 3.78] took no medication and seven patients (CDAI = 283.9 ± 22.5) were administered 29 ± 18 mg prednisone/d. Body composition was evaluated by isotopic dilution and bioelectrical impedance analysis, and 24-h energy expenditure and basal metabolic rate were measured in a respiratory chamber. Fat-free mass was not significantly different among groups, whereas fat mass was lower in patients than in control subjects. Energy intake was higher in treated patients than in both untreated patients (P = 0.004) and control subjects (P = 0.005). Fecal losses were not significantly different between untreated patients and control subjects, but were higher (and proportional to the CDAI) in treated patients than in control subjects (P = 0.001). Metabolizable energy was not significantly different among groups, whereas energy balance was significantly higher in treated patients than in both control subjects (P = 0.0057) and untreated patients (P = 0.018). Nitrogen balance was mildly negative in treated patients compared with both control subjects and untreated patients, but not significantly so. In conclusion, prednisone treatment in Crohn disease patients stimulates food intake, promoting an overall positive energy balance despite large fecal nutrient losses.
Urology, 1997
Objectives. To compare the plasma levels of vitamin B,, and folic acid following resection of ile... more Objectives. To compare the plasma levels of vitamin B,, and folic acid following resection of ileocecal or ileal segments used for orthotopic bladder substitution. Methods. Hemoglobin, hematocrit, and plasma levels of vitamin B,> and folic acid were measured in 34 patients with ileocecourethrostomy (ICUS) and in 16 patients with ileal reservoir (IR), with a mean follow-up of 59.8 k 41.9 months. The results were compared with regard to both the type of operation and the length of time since surgery. Results. The level of folic acid was normal in all patients. The mean level of vitamin B,2 in the ICUS group was 413.67 2 160.45 ng/mL compared to 257.63 2 12 1.36 for the IR group. This difference was statistically significant. In the IR group, 18.75% of the patients had a level of vitamin B,, below normal. Conclusions. There is a tendency for vitamin B, 2 levels to fall in patients in whom the ileum is used. Resection of the ileocecal segment including the junction does not alter the level of vitamin B,*. UROLOGY 50:
Urology, 1999
Objectives. To compare acid-base and electrolyte balance in ileocecal and ileal neobladders. Meth... more Objectives. To compare acid-base and electrolyte balance in ileocecal and ileal neobladders. Methods. Acid-base and electrolyte balance were studied in 45 patients with an ileocecourethrostomy and 18 patients with an ileal reservoir. The mean follow-up was 51 months. Results were compared with regard to both the type of operation and the time since surgery. Results. No significant differences were found with regard to either the type of operation or the length of follow-up. A preserved renal function is important in maintaining a healthy status. Conclusions. The use of 35 to 40 cm of ileum or 10 cm of cecum with the ileocecal junction seems to be safe even after a long follow-up. The length rather than the kind of bowel used for bladder replacement appears to be important in safeguarding hydroelectrolyte and acid-base homeostasis. This is particularly true in the presence of preserved renal function.
Obesity Surgery, 1998
The goal of the present work is to present an effective surgical approach for the treatment of a ... more The goal of the present work is to present an effective surgical approach for the treatment of a medically-resistant form of hyperlipidemia. Two siblings with familial lipoprotein-lipase deficiency and subsequent hyperchylomicronemia, widespread skin xanthomas and severe insulin-resistant diabetes mellitus came to our observation after several unsuccessful attempts at medical treatment. In order to lower plasma lipids through lipid malabsorption, a modified bilio-pancreatic diversion operation was employed. The rationale in deciding to use this surgical approach was based also on the likely hypothesis that diabetes, in these subjects, was secondary to high circulating and tissue levels of lipids. Insulin sensitivity in the two treated subjects, as well as in 24 healthy volunteers constituting the control group, was assessed by euglycemic hyperinsulinemic clamp and indirect calorimetry, obtaining total end-clamp glucose uptake (M) and end-clamp glucose oxidation (ECGO) rates. Within 3 weeks of surgery, plasma triglycerides and cholesterol levels had decreased from 4500 and 500 mg/dl (with dietary restrictions) to lower than 450 and 150 mg/dl (on a free, lipid-rich diet) respectively. Fasting plasma glucose levels had decreased from above 300 (under daily repeated subcutaneous injections of insulin) to 80-100 mg/dl (without administration of insulin or oral hypoglycemic agents). Body weight and fat free mass were maintained in both subjects after surgery. In both patients, before surgery M and ECGO were significantly lower than in normal subjects, while after surgery they were not significantly different from normal subjects, confirming the positive metabolic effect of the operation. The surgical option used in these patients may represent an interesting and effective new possibility for treatment of those severe cases of hyperlipemia leading otherwise to metabolic complications and a low quality of life.
Finance and Stochastics, 2012
For utility maximization problems under proportional transaction costs, it has been observed that... more For utility maximization problems under proportional transaction costs, it has been observed that the original market with transaction costs can sometimes be replaced by a frictionless shadow market that yields the same optimal strategy and utility. However, the question of whether or not this indeed holds in generality has remained elusive so far. In this paper we present a counterexample which shows that shadow prices may fail to exist. On the other hand, we prove that short selling constraints are a sufficient condition to warrant their existence, even in very general multi-currency market models with possibly discontinuous bid-ask-spreads.
Finance and Stochastics, 2010
We present an optimal investment theorem for a currency exchange model with random and possibly d... more We present an optimal investment theorem for a currency exchange model with random and possibly discontinuous proportional transaction costs. The investor's preferences are represented by a multivariate utility function, allowing for simultaneous consumption of any prescribed selection of the currencies at a given terminal date. We prove the existence of an optimal portfolio process under the assumption of asymptotic satiability of the value function. Sufficient conditions for asymptotic satiability of the value function include reasonable asymptotic elasticity of the utility function, or a growth condition on its dual function. We show that the portfolio optimization problem can be reformulated in terms of maximization of a terminal liquidation utility function, and that both problems have a common optimizer.
Digestive Diseases and Sciences, 1996
Resting ener D' expenditure (REE) was measured by indirect calorimet U and body composition was a... more Resting ener D' expenditure (REE) was measured by indirect calorimet U and body composition was assessed by both direct (bioimpedance) and indirect (anthropometl-y) methods in 20 hospitalized patients with biopsy-proven ileal Crohn's disease and in a group of 16 healthy volunteers matched for sex, age, and height with the patient group. The Crohn's disease activity index was below 120 in all patients studied, who were treated with a low dose of corticosteroids (1).2-(1.3 m,,/k,, bodv wt of prednisone). The averaee weight of Crohn's patients was significantly lower than that of controls (55.70 vs 70.50 kg, P < 0.001) due to both lower tilt mass (9.97 vs 18.30 kg, P < 0.0111) and lower lean body mass (45.72 vs 52.21) kg, P < 0.02). The average REE was significantly higher in the control group (1785.42 _+ 7.5(13 vs 1559.1 _+ 48.39 kcal/day, P < ().()(11). However, these differences disappeared when REE was normalized by lean body mass (LBM) (34.49 _+ 2.56 vs 34.704 _+ 3.75 kcal/kg LBM P = NS). The nonprotein respirato U quotient was significantly lower in the patient group (0.H23 +_ 0.()31 vs (I.882 _+ 0.012, P < 0.(125), indicating an increased lipid oxidation. This increased lipid oxidation might explain the reduced fat stores found in the group of Crohn's patients, 9 sU~ee,,,t, ~stlne"-also that a sulficientlv, lipid-rich diet could be useful in their nutritional mana,c-= ment.
Diabetologia, 1997
The aim of the present study was to measure whole body glucose uptake (M) and oxidation rate by e... more The aim of the present study was to measure whole body glucose uptake (M) and oxidation rate by euglycaemic hyperinsulinaemic clamp and indirect calorimetry in 7 morbidly obese subjects (BMI > 40 kg/m 2) at three time points: before biliopancreatic diversion (BPD) surgery (Ob); 3 months after surgery (PO I); and after reaching stable body weight, at least 2 years after surgery (PO II). A group of 7 control subjects (C), matched groupwise for sex, age and BMI with PO II patients, was also studied. The M value at PO I was significantly higher than at Ob (49.12 ± 8.57 vs 18.14 ± 8.57 m mol ⋅ kg −1 ⋅ min −1). No statistical difference was observed between the PO II and C groups. Similarly, glucose oxidation rate was significantly increased at PO I with respect to Ob (24.2 ± 7.23 vs 9.42 ± 3.91 m mol ⋅ kg −1 ⋅ min −1) and was not significantly different between PO II and C.
Clinical Nutrition, 1997
vs 1.3 _+ 0.1% on D5; P< 0.001), RBC (0.7 _+ 0.1 on D1 vs 1.0 _+ 0.1% on D5; P< 0.01), and plasma... more vs 1.3 _+ 0.1% on D5; P< 0.001), RBC (0.7 _+ 0.1 on D1 vs 1.0 _+ 0.1% on D5; P< 0.01), and plasma PL (1.2 _+ 0.4 on D1 vs 2.9 + 0.3 on D5; P< 0.025). DHA (22:6n-3) content was much less affected. Of interest, changes of EPA (and AA) in platelets and WBC (not shown), measured at the end of each infusion in 4 subjects, were substantial and very reproducible, independently of the initial EPA level (mean _+ SD
Clinica Chimica Acta, 1995
An improved gas-liquid chromatographic (GLC) method for the direct, simultaneous analysis of both... more An improved gas-liquid chromatographic (GLC) method for the direct, simultaneous analysis of both medium chain monocarboxylic acids (MCFA) and medium chain triglycerides (MCT) is reported. The calibration curve of MCFA and MCT is linear in the range from 30 ng to 1000 ng. Five nanograms for tricaproin (MCT-6), 10 ng for tricaprylin (MCT-8) and 15 ng for tricaprin (MCT-9) represent the GLC detection limits of MCT, while those of MCFA range from 40 to 15 ng depending on their chain length: the longer the chain length, the higher the detection limit. The recovery of MCFA range from 79 to 99% and that of MCT from 85 to 99%. An example of plasma concentration curves of MCT and MCFA after an intravenous bolus injection of an MCT emulsion (100 mg MCT/kgbw) in a patient with Crohn's disease is shown.
The American Journal of Cardiology, 1999
Fasting and postglucose hyperinsulinemia are recognized risk factors for acute coronary events. T... more Fasting and postglucose hyperinsulinemia are recognized risk factors for acute coronary events. The insulin reactivity of patients with acute coronary syndromes, however, has not been carefully compared with that of patients with chronic stable angina. We used Bergman&amp;amp;amp;amp;amp;amp;#39;s minimal model to analyze the insulin response to intravenous glucose in 21 subjects: 8 patients with previous (&amp;amp;amp;amp;amp;amp;gt;3 months) acute coronary syndrome but no effort-related angina; 6 patients with stable effort angina but no prior acute event; and 7 healthy controls. Diabetes mellitus, systemic hypertension, dyslipidemias, and obesity were excluded. All patients underwent coronary angiography. Insulin sensitivity, glucose effectiveness, and glucose tolerance were determined from insulin and glucose concentrations measured frequently up to 3 hours after a 0.33 g/kg intravenous glucose bolus. Patients with previous unstable angina or acute myocardial infarction had less extensive disease at angiography than patients with stable angina (p = 0.007). Both patient groups had higher basal and 180-minute insulinemia than controls (p &amp;amp;amp;amp;amp;amp;lt;0.0007). However, patients with stable angina did not differ significantly from controls with regard to early and late insulinemic response to glucose. In contrast, patients with previous acute onset of ischemia had significantly greater 180-minute integrated insulinemia (p = 0.04) and reduced insulin sensitivity (p = 0.05) after the glucose challenge than did the stable angina group. These data suggest that patients with acute presentation of coronary artery disease, compared with patients with uncomplicated chronic stable angina, have an impaired insulin response to glucose despite less extensive coronary disease at angiography.
American Journal of Physiology-Endocrinology and Metabolism, 1999
The kinetics of the triglyceride of dodecanedioic acid (TGDA) has been investigated in 30 male Wi... more The kinetics of the triglyceride of dodecanedioic acid (TGDA) has been investigated in 30 male Wistar rats after a rapid intravenous bolus injection. TGDA and its product of hydrolysis, nonesterified dodecanedioic acid (NEDA), were measured in plasma samples taken at different times using an improved high-performance liquid chromatographic method. The 24-h urinary excretion of TGDA was 1.54 ± 0.37 μmol, corresponding to ∼0.67% of the administered amount. Several kinetics models were considered, including central and peripheral compartments for the triglyceride and the free forms and expressing transports between compartments with combinations of linear, carrier-limited, or time-varying mechanisms. The parameter estimates of the kinetics of TGDA and of NEDA were finally obtained using a three-compartment model in which the transfer of TGDA to NEDA was assumed to be linear, through a peripheral compartment, and the tissue uptake of NEDA was assumed to be carrier limited. TGDA had a la...
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Papers by Giuseppe Benedetti