180 research outputs found
Bis(L-Amino Acid Amidato)Copper(II) Complexes as Chiral Eluents in the Enantiomeric Separation of D,L-Dansylamino Acids by Reversed-Phase High-Performance Liquid Chromatography
No full textGlucose kinetics and splanchnic uptake following mixed meal ingestion in cirrhotic-diabetic subjects.
No full textAlthough 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 deficienc
Differences in estimates of forearm protein synthesis between leucine and phenylalanine tracers following unbalanced amino acid infusion.
No full textWe 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 exclude
Protein metabolism in glucagonoma.
No full textAlthough protein wasting and reduced amino acid concentrations are common findings in glucagonoma patients, the mechanisms underlying these alterations are unclear. Therefore, we studied basal postabsorptive leucine, phenylalanine and tyrosine turnover following L-[D3]-Leucine, L-[D5]-Phenylalanine and L-[D2]-Tyrosine i.v. infusions in one male and one female patient with glucagonoma, compared with healthy control volunteers. Plasma amino acid concentrations were reduced (-40 to 80%, delta >2 SD vs. control subjects) in both patients. Plasma leucine, phenylalanine and tyrosine rates of appearance in patients with glucagonoma were similar to values in the control subjects, except leucine rate of appearence in the female patient with glucagonoma (+ approximately 30%, delta >2 SD). In contrast, the intracellular leucine rate of appearence, reflecting protein degradation, was considerably increased in both patients (+60-80%, delta >2 SD). Phenylalanine hydroxylation was moderately higher only in the male patient with glucagonoma (+ approximately 30%, delta >2 SD). Leucine, phenylalanine and tyrosine clearances (+100-300%), as well as phenylalanine hydroxylative clearance (+75-100%) were also increased in the patients. In conclusion, whole-body protein breakdown is enhanced in patients with glucagonoma compared with healthy control subjects. Phenylalanine hydroxylative clearance is also higher. Reduced plasma amino acid concentrations are probably due, at least in part, to their increased clearance. These alterations could contribute to the determination of the catabolic state of the glucagonoma syndrome
Relationships between phenylalanine hydroxylation and plasma aromatic amino acid concentrations in humans.
No full textWe investigated the relationships between phenylalanine hydroxylation (Phe Hy) and plasma concentrations of phenylalanine, tyrosine, and glucagon in healthy male volunteers (N = 13; age, 29 +/- 3 years). Phe Hy, as well as the Phe and Tyr rate of appearance (Ra), were measured during L-[2H5]-Phe and L-[2H2]-Tyr continuous intravenous (i.v.) infusions both under basal postabsorptive conditions (N = 13) and following divergent changes of plasma aromatic amino acids (AAA) concentrations. Namely, AAA were increased by administration of a balanced synthetic mixed meal (n = 6) or selectively decreased by i.v. infusion of insulin along with a Phe-deficient, Tyr and tryptophan-deprived amino acid mixture ([IAA] n = 7). Following the meal, plasma Phe (54 +/- 3 to 81 +/- 12 micromol/L), plasma Tyr (54 +/- 4 to 91 +/- 7), Phe Hy (0.09 +/- 0.01 to 0.15 +/- 0.02 micromol/kg x min), Phe Ra (0.65 +/- 0.04 to 0.96 +/- 0.07), and Tyr Ra (0.51 +/- 0.03 to 0.93 +/- 0.11) all significantly increased (P < or = .05 v basal). IAA infusion significantly decreased plasma Phe (to 47 +/- 3 micromol/L), plasma Tyr (to 25 +/- 4), Phe Hy (to 0.07 +/- 0.004 micromol/kg x min), and Tyr Ra (to 0.29 +/- 0.02; all P < or = .05 v sal), while Phe Ra did not change (0.64 +/- 0.04, NS). Plasma glucagon did not change in the three experimental periods (basal, 85 +/- 7; meal, 72 +/- 10; IAA, 92 +/- 14 pg/mL; NS). Using linear regression analysis, plasma Phe was positively related to both Phe Hy (R2 = .76, P < .001) and plasma Tyr (R2 = .80, P < .001); Phe Hy and plasma Tyr were also significantly correlated (R2 = .60, P < .001). No correlation was found between Phe Hy and basal plasma glucagon (R2 = .04, NS). Using multiple regression analysis with plasma Tyr as the dependent variable, plasma Phe was still correlation with plasma Tyr (t = 4.29, P = .0002), while the relationship between Phe Hy and plasma Tyr was no longer significant (t = 0.69, P = .49). These data indicate that plasma Phe is closely associated with its own hydroxylative disposal in humans, and confirm that Phe conversion to Tyr may play a physiological role in maintaining balanced plasma phenylalanine and tyrosine concentrations
Therapeutic strategies for sarcopenic obesity: a systematic review
No full textPURPOSE OF REVIEW: Tough plenty of literature investigated therapeutic options for body composition changes targeting elderly people, evidence concerning potential treatments of sarcopenic obesity as a unique condition is scarce. The aim of the present review was to summarize recent evidence regarding treatment of sarcopenic obesity in adult and older individuals. RECENT FINDINGS: Exercise-based interventions were effective in ameliorating lean mass or sarcopenia-related indices and reducing total adiposity. Importantly, in one study, modifications of body composition were obtained in the absence of significant changes in body mass index. The majority of studies relied on resistance training, and all provided with beneficial effects in body composition. Conversely, effects in terms of muscle strength and functional ability were heterogeneous. Electrical acupuncture and whole-body electromyostimulation associated with nutritional supplementation resulted to be novel effective strategies in inducing body composition changes. Nonetheless, findings from nutritional supplementations are not conclusive, leading to conflicting results on strength and functional outcomes. SUMMARY: Specific interventions could improve sarcopenic obesity, but overall significance is limited by scarcity of data and lack of uniformity in the definition of sarcopenic obesity itself. Further research should clarify optimal treatment options for sarcopenic obesity in age classes other than the geriatric population
Moderate caloric restriction, but not physiological hyperleptinemia per se, enhances mitochondrial oxidative capacity in rat liver and skeletal muscle--tissue-specific impact on tissue triglyceride content and AKT activation.
No full textThe study aimed at determining, in lean tissues from nonobese rats, whether physiological hyperleptinemia with leptin-induced reduced caloric intake and/or calorie restriction (CR) per se: 1) enhance mitochondrial-energy metabolism gene transcript levels and oxidative capacity; and 2) reduce triglyceride content. Liver and skeletal muscles were collected from 6-month-old Fischer 344 rats after 1-wk leptin sc infusion (0.4 mg/kg . d: leptin + approximately 3-fold leptinemia vs. ad libitum-fed control) or moderate CR (-26% of those fed ad libitum) in pair-fed animals (CR). After 1 wk: 1) leptin and CR comparably enhanced transcriptional expression of mixed muscle mitochondrial genes (P < 0.05 vs. control); 2) CR independently increased (P < 0.05 vs. leptin-control) hepatic mitochondrial-lipooxidative gene expression and oxidative capacity; 3) hepatic but not muscle mitochondrial effects of CR were associated (P < 0.01) with increased activated insulin signaling at AKT level (P < 0.05 vs. leptin-control); 4) liver and muscle triglyceride content were comparable in all groups. In additional experiments, assessing time course of posttranscriptional CR effects, 3-wk superimposable CR (P < 0.05): 1) increased both liver and muscle mitochondrial oxidative capacity; and 2) selectively reduced muscle triglyceride content. Thus, in nonobese adult rat: 1) moderate CR induces early increments of mitochondrial-lipooxidative gene expression and time-dependent increments of oxidative capacity in liver and mixed muscle; 2) sustained moderate CR alters tissue lipid distribution reducing muscle but not liver triglycerides; 3) mitochondrial-lipid metabolism changes are tissue-specifically associated with hepatic AKT activation; 4) short-term physiological hyperleptinemia has no independent stimulatory effects on muscle and liver mitochondrial-lipooxidative gene expression. Increased lean tissue oxidative capacity could favor substrate oxidation over storage during reduced nutrient availability
Effect of protic compounds on ethylene polymerization by Hf-Ti supported catalysts
No full textThe effect was investigated of the addition of different protic compounds, such as water, n-butanol, butanoic acid and methyl ethyl ketone, to triisobutylaluminium used as the cocatalyst for an Hf-Ti bimetallic catalyst supported on magnesium dichloride (Ti1.0Hf1.3Mg2.0Al0.85Cl12.45) in the polymerization of ethylene. All the above compounds show a similar behaviour by decreasing catalyst activity, increasing polymer molecular weight and narrowing polymer molecular weight distribution. Minor differences are observed in the end-group unsaturations. An attempt has been made to correlate these effects to the interaction of hafnium and titanium sites with the reaction products from AlR3 and the different protic compounds
Structural features of 4-methyl-1-pentene polymers prepared with different transition metal catalysts
No full textHomopolymerization of 4-methyl-1-pentene carried out in the presence of catalysts containing variable relative amounts of Ti, Hf and Mg indicates that molecular weight and stereoregularity can be varied to an appreciable extent depending on catalyst nature and composition. A distinct behaviour of the various catalytic systems is also observed during the copolymerization of 4-methyl-1-pentene with monoalkenes such as propylene, 1-butene and 1-hexene. These data are discussed by underlining the important role of the transition metal in determining the features of polyolefins materials
Position statement of Italian Society of Obesity (SIO): Gestational Obesity
No full textpurposeGestational obesity (GO) presents a multifaceted challenge to maternal and fetal health, with an escalating prevalence and far-reaching consequences extending beyond pregnancy. this perspective statement by the Italian society of obesity (SIO) provides current insights into the diagnosis, maternal and fetal impacts, and treatment strategies for managing this pressing condition.methodsThis article provides a comprehensive review of the maternal and fetal effects of GO and provides suggestions on strategies for management. comprehensive review was carried out using the MEDLINE/PubMed, CINAHL, EMBASE, and cochrane Library databases.ResultsThe diagnosis of GO primarily relies on pre-pregnancy body mass index (BMI), although standardized criteria remain contentious. anthropometric measures and body composition assessments offer valuable insights into the metabolic implications of GO. Women with GO are predisposed to several health complications, which are attributed to mechanisms such as inflammation and insulin resistance. Offspring of women with GO face heightened risks of perinatal complications and long-term metabolic disorders, indicating intergenerational transmission of obesity-related effects. while nutritional interventions are a cornerstone of management, their efficacy in mitigating complications warrants further investigation. additionally, while pharmacological interventions have been explored in other contexts, evidence on their safety and efficacy specifically for GO remains lacking, necessitating further investigation.conclusionGO significantly impacts maternal and fetal health, contributing to both immediate and long-term complications. effective management requires a multifaceted approach, including precise diagnostic criteria, personalized nutritional interventions, and potential pharmacological treatments. these findings underscore the need for individualized care strategies and further research to optimize outcomes for mothers and their offspring are needed. Enhanced understanding and management of GO can help mitigate its intergenerational effects, improving public health outcomes.Level of evidence: Level V narrative review. conclusionGO significantly impacts maternal and fetal health, contributing to both immediate and long-term complications. effective management requires a multifaceted approach, including precise diagnostic criteria, personalized nutritional interventions, and potential pharmacological treatments. These findings underscore the need for individualized care strategies and further research to optimize outcomes for mothers and their offspring are needed. enhanced understanding and management of GO can help mitigate its intergenerational effects, improving public health outcomes.Level of evidence: level V narrative review
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