Investigating isotopic markers for hazelnut geographical authentication: Promising variables and potential applications

Hazelnuts' features and price are influenced by their geographical origin, making them susceptible to fraud, especially counterfeit claims regarding their provenance. Stable isotope analysis is a recognised approach to establish the geographical origin of foods, yet its potential in hazelnut authentication remains unexplored. In this prospective study, we assessed multiple isotopic markers in hazelnuts from different origins and evaluated the most promising variables for geographical authentication by chemometric tools. Our findings indicate that bulk δ18O, along with δ2H and δ13C in the main fatty acid methyl esters, exhibit significant potential in discriminating geographical origins, and 87Sr/86Sr analysis could serve as a proficient confirmatory tool. Though no single marker alone can differentiate between all the studied origins, employing a multi-isotopic approach based on PLS-DA models achieved up to 92.5 % accuracy in leave-10 %-out cross-validation. These findings will probably lay the groundwork for developing robust models for hazelnut geographical authentication based on larger datasets.

Prospective exploration of hazelnut's unsaponifiable fraction for geographical and varietal authentication: A comparative study of advanced fingerprinting and untargeted profiling techniques

This study compares two data processing techniques (fingerprinting and untargeted profiling) to authenticate hazelnut cultivar and provenance based on its unsaponifiable fraction by GC-MS. PLS-DA classification models were developed on a selected sample set (n = 176). As test cases, cultivar models were developed for "Tonda di Giffoni" vs other cultivars, whereas provenance models were developed for three origins (Chile, Italy or Spain). Both fingerprinting and untargeted profiling successfully classified hazelnuts by cultivar or provenance, revealing the potential of the unsaponifiable fraction. External validation provided over 90 % correct classification, with fingerprinting slightly outperforming. Analysing PLS-DA models' regression coefficients and tentatively identifying compounds corresponding to highly relevant variables showed consistent agreement in key discriminant compounds across both approaches. However, fingerprinting in selected ion mode extracted slightly more information from chromatographic data, including minor discriminant species. Conversely, untargeted profiling acquired in full scan mode, provided pure spectra, facilitating chemical interpretability.

Effect of feeding olive pomace acid oil on pork lipid composition, oxidative stability, colour, and sensory acceptance

One of the targets of the meat industry is to reduce production costs and to increase the sustainability of the food chain, which has driven the attention towards the use of by-products as feed ingredients. Acid oils are fat by-products coming from the chemical refining process of edible oils, with a high energy value and that are approved as feed ingredients in the European Union. However, meat producers are hesitant to utilise them due to their varying composition and the limited understanding of their impact on animal performance and meat quality. The objective of this study was to evaluate the effects of using olive pomace acid oil (OPAO) instead of its corresponding crude olive pomace oil (OPO) or crude palm oil (PO) in pig diets on lipid composition, lipid oxidation and quality of pork loin (longissimus dorsi), fresh and after commercial refrigerated storage for 8 days. The experimental design consisted of feeding pigs with four diets supplemented with a 5% of PO, OPO, OPAO or a blend (B) of PO and OPAO (50:50, w/w). Fresh and refrigerated pork loin samples were assessed for fatty acid profile; tocopherol (T) and tocotrienol (T3) composition; lipid oxidative stability with the ferrous oxidation-xylenol orange method; 2-thiobarbituric acid (TBA) value; volatile compounds; colour; and sensory acceptance. Results showed that refrigeration reduced the total T + T3 levels and increased the TBA values and the volatile compound concentrations. The refrigerated storage also affected the instrumental colour parameters (L*, a* and b*) but not the overall acceptance of pork. Regarding the diet, pork from OPAO diet showed a higher unsaturated-to-saturated fatty acid ratio than pork from PO and B diets. The lowest T + T3 concentration was found in OPO and OPAO fresh pork and in OPAO refrigerated pork. The oxidative stability of fresh pork was lower for OPAO than for PO diet, but no significant effect of the diet was observed for this parameter in refrigerated pork. The TBA values and volatile compound concentrations of fresh pork were not affected by the diet. After refrigeration, OPAO pork had the highest TBA value and volatile compound concentrations. In any case, colour and consumer acceptance of pork were not affected by diet. In conclusion, in order to upcycle acid oils in pig diets, and considering results on the lipid oxidative stability of pork, it would be preferable to add the OPAO used in this study blended with PO.

Human Variability in Carboxylesterases and carboxylesterase-related Uncertainty Factors for Chemical Risk Assessment

Carboxylesterases (CES) are an important class of enzymes involved in the hydrolysis of a range of chemicals and show large inter-individual variability in vitro. An extensive literature search was performed to identify in vivo probe substrates for CES1 and CES2 together with their protein content and enzymatic activity. Human pharmacokinetic (PK) data on Cmax, clearance, and AUC were extracted from 89 publications and Bayesian meta-analysis was performed using a hierarchical model to derive CES-related variability distributions and related uncertainty factors (UF). The CES-related variability indicated that 97.5% of healthy adults are covered by the kinetic default UF (3.16), except for clopidogrel and dabigatran etexilate. Clopidogrel is metabolised for a small amount by the polymorphic CYP2C19, which can have an impact on the overall pharmacokinetics, while the variability seen for dabigatran etexilate might be due to differences in the absorption, since this can be influenced by food intake. The overall CES-related variability was moderate to high in vivo (<CV 50%), which might be due to possible polymorphism in the enzyme but also to the small sample size available per chemical. The presented CES-related variability can be used in combination with in vitro data to derive pathway-specific distributions.

Water quality and human health: A simple monitoring model of toxic cyanobacteria growth in highly variable Mediterranean hot dry environments

Due to population growth, urbanization and economic development, demand for freshwater in urban areas is increasing throughout Europe. At the same time, climate change, eutrophication and pollution are affecting the availability of water supplies. Sicily, a big island in southern Italy, suffers from an increasing drought and consequently water shortage. In the last decades, in Sicilian freshwater reservoirs several Microcystis aeruginosa and more recently Planktothrix rubescens blooms were reported. The aims of the study were: (1) identify and quantify the occurring species of cyanobacteria (CB), (2) identify which parameters, among those investigated in the waters, could favor their growth, (3) set up a model to identify reservoirs that need continuous monitoring due to the presences, current or prospected, of cyanobacterial blooms and of microcystins, relevant for environmental and, consequentially, for human health. Fifteen artificial reservoirs among the large set of Sicilian artificial water bodies were selected and examined for physicochemical and microbiological characterization. Additional parameters were assessed, including the presence, identification and count of the cyanobacterial occurring species, the measurement of microcystins (MCs) levels and the search for the genes responsible for the toxins production. Principal Component Analysis (PCA) was used to relate environmental condition to cyanobacterial growth. Water quality was poor for very few parameters, suggesting common anthropic pressures, and PCA highlighted clusters of reservoirs vulnerable to hydrological conditions, related to semi-arid Mediterranean climate and to the use of the reservoir. In summer, bloom was detected in only one reservoir and different species was highlighted among the Cyanobacteria community. The only toxins detected were microcystins, although always well below the WHO reference value for drinking waters (1.0 μg/L). However, molecular analysis could not show the presence of potential cyanotoxins producers since a few numbers of cells among total could be sufficient to produce these low MCs levels but not enough high to be proved by the traditional molecular method applied. A simple environmental risk-based model, which accounts for the high variability of both cyanobacteria growth and cyanotoxins producing, is proposed as a cost-effective tool to evaluate the need for monitoring activities in reservoirs aimed to guarantee supplying waters safety.

High dose brachytherapy with non sealed 188Re (rhenium) resin in patients with non-melanoma skin cancers (NMSCs): single center preliminary results

Background and aim

High dose brachytherapy using a non sealed ¹⁸⁸Re-resin (Rhenium-SCT®, Oncobeta® GmbH, Munich, Germany) is a treatment option for non-melanoma skin cancer (NMSC). The aim of this prospective study was to assess the efficacy and the safety of a single application of Rhenium-SCT® in NMSC.

Materials and method

Fifty consecutive patients (15F, 35 M, range of age 56–97, mean 81) showing 60 histologically proven NMSCs were enrolled and treated with the Rhenium-SCT® between October 2017 and January 2020. Lesions were located on the face, ears, nose or scalp (n = 46), extremities (n = 9), and trunk (n = 5). Mean surface areas were 7.0 cm² (1–36 cm²), mean thickness invasion was 1.1 mm (0.2–2.5 mm), and mean treatment time was 79 min (21–85 min). Superficial, mean, and target absorbed dose were 185 Gy, 63 Gy, and 31 Gy respectively. Patients were followed-up at 14, 30, 60, 90, and 180 days posttreatment, when dermoscopy and biopsy were performed. Mean follow-up was 20 months (range 3–33 months). Early skin toxicity was classified according to Common Terminology Criteria for Adverse Events (CTCAE). Cosmetic results were evaluated after at least 12 months according to Radiation Therapy Oncology Group (RTOG) scale.

Results

At 6 months follow-up, histology and dermoscopy were available for 54/60 lesions, of which 53/54 (98%) completely responded. One patient showed a 1-cm² residual lesion that was subsequently surgically excised. Twelve months after treatment, 41/41 evaluable lesions were free from relapse. Twenty four months after treatment, 23/24 evaluable lesions were free of relapse. In 56/60 lesions early side effects, resolving within 32 days were classified as grades 1–2 (CTCAE). In the remaining 4/60 lesions, these findings were classified as grade 3 (CTCAE) and lasted up to 8–12 weeks but all resolved within 90 days. After at least 12 months (12–33 months), cosmetic results were excellent (30 lesions) or good (11 lesions).

Conclusion

High dose brachytherapy with Rhenium-SCT® is a noninvasive, reasonably safe, easy to perform, effective and well-tolerated approach to treat NMSCs, and it seems to be a useful alternative option when surgery or radiation therapy are difficult to perform or not recommended. In our population 98% of the treated lesions resolved completely after a single application and only one relapsed after 2 years. Larger patients’ population and longer follow-up are needed to confirm these preliminary data and to find the optimal dose to administer in order to achieve complete response without significant side effects.

Sclerodermiform basal cell carcinomas vs. other histotypes: analysis of specific demographic, clinical and dermatoscopic features

BACKGROUND

Among the various types of basal cell carcinoma, the sclerodermiform variant has a high risk of recurrence and local invasiveness. A systematic description of the dermatoscopic features associated with specific body localization is lacking.

OBJECTIVES

To describe the clinical and dermoscopic features of sclerodermiform basal cell carcinoma (BCC) according to localization in the body confronting with superficial and nodular types.

METHODS

Clinical and dermoscopic images of sclerodermiform, nodular and superficial BCCs were retrospectively evaluated to study the location in the various body districts, maximum diameter, clinical appearance of the lesion, features of edges and presence or absence of specific dermatoscopic criteria of BCCs.

RESULTS

We examined 291 histopathologically proven BCCs showing that in nodular BCCs, classical arborizing vessels were more frequently found in the body macro-area (trunk and limbs; n = 46, 97.9%) than in the head/neck area (n = 43, 82.7%); within sclerodermiform BCCs, short arborizing vessels were found more frequently in the head/neck district (n = 35, 49.3%) than in the body (n = 6, 23.1%; P-value 0.02); within nodular BCCs, multiple blue-grey dots and globules were more frequently found on the trunk (n = 23, 48.9%) than in the head/neck district (n = 12, 23.1%; P-value 0.01). In sclerodermiform BCCs, ulceration was found more frequently in the head/neck district (n = 38, 53.5%) than in the body (n = 4, 15.4%; P-value > 0.01), and in superficial BCCs, ulceration was found more frequently in the head/neck district (n = 5, 38.5%) than in the body (n = 8, 9.8%; P-value 0.02).

CONCLUSION

Our study shows that superficial BCC are found frequently in the head/neck district dermoscopically characterized by ulceration and arborizing vessels; nodular BCCs are more frequently found in the body than in the head/neck district, and the dermoscopic pattern is characterized by the combination of three features: (i) classical arborizing vessels, (ii) multiple blue-grey dots and (iii) globules. Instead, sclerodermiform BCC is preferentially located in areas at high-moderate risk of recurrence; if pink-white areas and/or fine arborizing vessels are seen, clinicians should consider this diagnosis. Furthermore, location-specific dermatoscopic criteria have been described.

Bayesian meta-analysis of inter-phenotypic differences in human serum paraoxonase-1 activity for chemical risk assessment

Human variability in paraoxonase-1 (PON1) activities is driven by genetic polymorphisms that affect the internal dose of active oxons of organophosphorus (OP) insecticides. Here, an extensive literature search has been performed to collect human genotypic frequencies (i.e. L55M, Q192R, and C-108T) in subgroups from a range of geographical ancestry and PON1 activities in three probe substrates (paraoxon, diazoxon and phenyl acetate). Bayesian meta-analyses were performed to estimate variability distributions for PON1 activities and PON1-related uncertainty factors (UFs), while integrating quantifiable sources of inter-study, inter-phenotypic and inter-individual differences. Inter-phenotypic differences were quantified using the population with high PON1 activity as the reference group. Results from the meta-analyses provided PON1 variability distributions and these can be implemented in generic physiologically based kinetic models to develop quantitative in vitro in vivo extrapolation models. PON1-related UFs in the Caucasian population were above the default toxicokinetic UF of 3.16 for two specific genotypes namely -108CC using diazoxon as probe substrate and, -108CT, -108TT, 55MM and 192QQ using paraoxon as probe substrate. However, integration of PON1 genotypic frequencies and activity distributions showed that all UFs were within the default toxicokinetic UF. Quantitative inter-individual differences in PON1 activity are important for chemical risk assessment particularly with regards to the potential sensitivity to organophosphates' toxicity.

Homocysteine plasma levels in psoriasis patients: our experience and review of the literature

BACKGROUND

People with psoriasis are at higher cardiovascular risk. Plasma levels of homocysteine over the normal range have been recognized as marker of cardiovascular risk. Psoriasis patients express higher levels of plasma homocysteine than healthy people.

OBJECTIVE

Our study aims to investigate the correlation between homocysteinaemia, severity and duration of psoriasis and psoriasis arthritis, and to evaluate the effect of a 12-week administration of a target therapy for psoriasis on homocysteinaemia.

METHODS

Fifty-two psoriasis patients (study group) submitted to different kind of therapy for psoriasis (biological, systemic not biological and topical) and 24 healthy Italian subject (control group) were evaluated for their plasmatic homocysteine levels, both at baseline (T0) and 12 weeks after they a specific therapy for psoriasis.

RESULTS

A significant difference between the homocysteinaemia of psoriasis patients (mean 19.71 ± 11.16) and control group (13.90 ± 11.18), P < 0.05 (Fig. 1), was found at baseline (T0). The mean plasma levels of homocysteine were directly correlated with disease severity (P = 0.0401), but not with disease duration (P = 0.6018) or presence of arthritis (P = 0.6221) at baseline. None among the treatments administered to psoriasis patients caused a significant reduction in homocysteinaemia after 12 weeks of treatment.

CONCLUSION

Our results confirm that psoriasis patients with more severe disease, can have hyperhomocysteinaemia, without regard to disease duration or joint involvement. Hyperhomocysteinaemia is not influenced by a target therapy for psoriasis and it is as greater as psoriasis severity. However, limitation of our study is the relatively small number of cases. Homocysteine plasmatic levels should be advisable as a further independent risk factor for cardiovascular disease in psoriasis patients.

Cell type-specific expression and localization of cytochrome P450 isoforms in tridimensional aggregating rat brain cell cultures

Within the Predict-IV FP7 project a strategy for measurement of in vitro biokinetics was developed, requiring the characterization of the cellular model used, especially regarding biotransformation, which frequently depends on cytochrome P450 (CYP) activity. The extrahepatic in situ CYP-mediated metabolism is especially relevant in target organ toxicity. In this study, the constitutive mRNA levels and protein localization of different CYP isoforms were investigated in 3D aggregating brain cell cultures. CYP1A1, CYP2B1/B2, CYP2D2/4, CYP2E1 and CYP3A were expressed; CYP1A1 and 2B1 represented almost 80% of the total mRNA content. Double-immunolabeling revealed their presence in astrocytes, in neurons, and to a minor extent in oligodendrocytes, confirming the cell-specific localization of CYPs in the brain. These results together with the recently reported formation of an amiodarone metabolite following repeated exposure suggest that this cell culture system possesses some metabolic potential, most likely contributing to its high performance in neurotoxicological studies and support the use of this model in studying brain neurotoxicity involving mechanisms of toxication/detoxication.

Detection of hazelnut oil in virgin olive oil by assessment of free sterols and triacylglycerols

Free sterols were evaluated as factors for discriminating between genuine virgin olive oil and hazelnut-mixed virgin olive oil. Numeric analyses of the results amplified the differences between groups. The application of this method to virgin olive oil samples and their mixtures with 10% hazelnut oil distinguished between genuine and nongenuine virgin olive oil with statistical certainty. Triacylglycerol analysis was tested for the same purpose by using parameter deltaECN42, but although it possessed a discriminating capacity, it alone could not distinguish the aforementioned groups with sufficient certainty. Free delta7-sterols data were combined with deltaECN42 data into a single discriminating function to improve differentiation and bring more ruggedness, and for detection of low amounts (10%) of hazelnut oil in virgin olive oil. In fact, the values obtained by addition of delta7-sterol data and deltaECN42 data showed a higher discriminating capacity than single parameters. In a single operation the method produced all the oil fractions necessary for analysis of free sterols and triacylglycerols with ECN42. Solid-phase extraction was applied in substitution of traditional chromatography on a silica column.

Determination of the presence of antioxidants deriving from sage and oregano extracts added to animal fat by means of assessment of the radical scavenging capacity by photochemiluminescence analysis

Herbs and their extracts with antioxidant capacity could be used directly as stabilisers of fat and indirectly as feed additives, in order to improve quality and shelf-life of meat and fat-containing food. In this work a sensitive analytical method is proposed for determination of the antioxidant activity measured by photochemiluminescence (PCL) in lard stabilised with extracts of sage (Salvia officinalis L.) or oreganum (Origanum vulgare L.). A prior step of purification of fat samples is required, in order to separate and concentrate the phenolics from lipidic substances. The method was validated by determination of recovery rate and repeatability. In addition fat samples originating from pigs fed with feed additives of Salviae folium or Origani herba were analysed to investigate the supposed antioxidative effects, that could increase the shelf-life of meat products. In contrast with lard mixed with extracts of sage or oregano, back fat samples originating from pigs fed with feed additives of the same herbs didn't show a higher antioxidant activity than the control group. On the one hand it seems possible to keep perishable fat-containing food longer by an addition of an extract of sage or oregano due to their antioxidative properties, on the other hand administration of feed additives of dried herbs to pigs had no effect on quality and shelf-life of fat obtained from these animals.

Coronary atherosclerosis in Type II diabetes: angiographic findings and clinical outcome

AIMS/HYPOTHESIS

Prevalence and incidence of coronary heart disease (CHD) are increased in patients with Type II (non-insulin-dependent) diabetes mellitus; whether this is entirely due to more extensive coronary atherosclerosis is, however, controversial.

METHODS

We analysed the clinical, angiographic and follow-up data of 2253 consecutive patients undergoing coronary angiography over the decade 1983-1992.

RESULTS

Abnormal coronary arteries (> or =50% stenosis) were found more frequently in diabetic than in non-diabetic subjects (85 vs 67%, p < 0.0001), the excess being explained by a higher prevalence of three-vessel disease (36 vs 17%, p < 0.0001). The sum of all angiographically detectable lumen stenoses (atherosclerosis score, ATS) was higher in diabetic than in non-diabetic subjects (352 +/- 232 vs 211 +/- 201 units, p < 0.0001). After adjusting for measured cardiovascular risk factors, diabetes was still associated with an excess ATS (114 units in men and 187 units in women, p < 0.0001 for both, p < 0.03 for the interaction ATS x sex). Within the diabetic group, the only variable that was independently (of sex and age) associated with ATS was serum cholesterol, whereas plasma glucose concentration, disease duration and type of treatment were not correlated with the severity of coronary atherosclerosis. In contrast, clinical grade proteinuria was not associated with a more diffuse coronary atherosclerosis either in diabetic (366 +/- 243 vs 354 +/- 233 units) or non-diabetic subjects (231 +/- 201 vs 207 +/- 197 units). Over a mean follow-up period of 88 months, 19% of diabetic patients compared with 10% of non-diabetic patients died of a cardiac cause (age and sex-adjusted odds ratio OR = 1.34 [1.14-1.57]). In a Cox model adjusting for age, sex and all major risk factors, diabetes was still associated with a significant excess risk of dying of a cardiac cause (OR = 1.37 [1.14-1.60]); this excess was similar to, and independent of, that carried by the presence of prior myocardial infarction in the whole population (OR = 1.42 [1.25-1.62]). Proteinuria was associated with a higher risk of cardiac death, particularly in diabetic patients, independently of coronary atherosclerosis (adjusted OR = 1.46 [1.03-1.99]).

CONCLUSION/INTERPRETATION

In patients undergoing angiography, diabetes, especially in women, is associated with more severe and diffuse coronary atherosclerosis which is not explained by either the traditional risk factors or the presence of proteinuria. On follow-up, these patients experience an excess of cardiac deaths, to which coronary atherosclerosis and proteinuria make independent, quantitative contributions.

Coronary artery disease and arterial hypertension: clinical, angiographic and follow-up data

OBJECTIVES

To evaluate how the presence of arterial hypertension affects coronary atherosclerosis and prognosis in patients with, or at high risk of, ischaemic heart disease.

DESIGN

Retrospective analysis of clinical records and follow-up data.

SETTINGS

Single referral centre for ischaemic heart disease.

SUBJECTS

All consecutive patients (n = 1700, 38% with hypertension) undergoing coronary angiography for the evaluation of ischaemic heart disease during 1983-92.

RESULTS

On angiography, the likelihood of having three-vessel disease was higher amongst hypertensives (odds ratio = 1.41; 95% confidence interval [CI] = 1.08-1.85) after adjustment for age, sex, and angina symptoms. The sum of all visible stenoses (an index of overall atherosclerotic involvement) was 19% higher in hypertensives (262 +/- 204 vs. 220 +/- 194 units, P < 0.005). By multivariate analysis, the presence of hypertension made a modest (+ 28 units), albeit statistically significant, independent contribution to the total atherosclerosis score. On follow-up (median = 96 months), cardiovascular mortality was slightly higher in the hypertensive patients than in the normotensive group (P < 0.05 in a Kaplan-Meier analysis), but a proportional hazard analysis adjusting for age and gender showed no significant independent contribution of hypertension. Hypertensive patients, however, remained at higher risk of non-fatal myocardial infarction following discharge (adjusted odds ratio = 1.21, 95% CI = 1.03-1.46; P < 0.05).

CONCLUSIONS

In this referral population, hypertension is a risk factor for presence of three-vessel disease. Distribution, severity and extension of coronary stenosis are similar to those of normotensive patients, and prognosis is only marginally affected.

Effects of troglitazone on insulin action and cardiovascular risk factors in patients with non-insulin-dependent diabetes

OBJECTIVE

Insulin resistance is a potential target for pharmacologic intervention in non-insulin-dependent diabetes. Troglitazone is being evaluated as an insulin enhancer in insulin resistant states.

RESEARCH DESIGN AND METHODS

We randomized 40 patients with non-insulin-dependent diabetes to diet plus placebo (n = 15) or diet plus troglitazone (n = 25; 200 mg/day) treatment for 8 weeks. Fasting endogenous glucose production (EGP, by the stable isotope technique) and whole-body insulin sensitivity (by the insulin suppression test) were measured at baseline and on days 3, 7, 14, 28, and 56 of treatment.

RESULTS

By day 56, fasting plasma glucose had risen from 12.0 +/- 0.9 to 12.8 +/- 1.2 mmol/L in the placebo group and had fallen from 12.4 +/- 0.6 to 11.3 +/- 0.6 mmol/L in the troglitazone group (p = 0.03). This was the result of small improvements in whole-body insulin sensitivity (steady-state plasma glucose during the insulin suppression test: from 11.09 +/- 1.1 to 10.3 +/- 0.8 mmol/L versus 13.8 +/- 1.0 to 10.0 +/- 0.9 mmol/L, placebo versus troglitazone; p = 0.01) and EGP (from 103% +/- 3% versus 96% +/- 2% of baseline, placebo versus troglitazone; p = 0.09). The time course of insulin action showed an early (first week of treatment) decrease in EGP in the troglitazone group that was maintained throughout, whereas steady-state plasma glucose levels began to diverge toward the end of treatment. The effects of insulin on plasma free fatty acid and potassium concentrations were not different between placebo and troglitazone. The cardiovascular risk profile (heart rate; serum triglycerides; total, low-density lipoprotein, and high-density lipoprotein cholesterol; proinsulin; uric acid; plasminogen activator inhibitor-1 antigen and activity; 24-hour blood pressure monitoring and urinary albumin excretion) was unaltered by troglitazone treatment.

CONCLUSIONS

Troglitazone as monotherapy for typical non-insulin-dependent diabetes had a modest anti-hyperglycemic effect and, at the dose used in this study, had no effect on cardiovascular risk factors.

Insulin action and age. European Group for the Study of Insulin Resistance (EGIR)

Evidence that age is associated with insulin resistance is discordant. We analyzed euglycemic insulin clamp (1 mU x min(-1) x kg(-1)) data collected at 20 centers throughout Europe from 1,146 men and women with normal glucose tolerance, ranging in age from 18 to 85 years. In the whole group, insulin action (as the M value) declined slightly with age (at a rate of 0.9 micromol x min(-1)-kg(-1) per decade of life, 95% CI = 0.4-1.3, P = 0.0002). When adjusted for BMI, this relationship was no longer statistically significant. The same result was obtained whether insulin action was expressed per kilogram of body weight or per kilogram of fat-free mass, expressed as the M:I ratio, or estimated from fasting plasma insulin concentrations. Subgroup analysis showed that a significant BMI-adjusted decrease in insulin action with age was present only in lean (BMI <25 kg/m2) women (a rate of 1.6 micromol x min(-1) x kg(-1) per decade, 95% CI = 0.6-2.5, P = 0.001), in whom percentage fat mass also increased with age (by 0.38% body weight per decade, P = 0.0007). Insulin action was positively associated with insulin suppression of circulating free fatty acids (FFAs) (+1.5 micromol x min(-1) x kg(-1) for each 10% increase in FFA suppression, P < 0.0001) in a multivariate model accounting for sex, BMI, age, and fasting FFA levels. Furthermore, insulin suppression of FFAs improved with age in men (2% per decade, P < 0.0001) but not in women. In the subgroup of lean women in whom insulin action declined with age, adding FFA suppression to a multiple regression equation canceled the association between age and insulin action. Thus, the small effect of age on insulin action could be adequately explained on the basis of age-related changes in body composition and substrate competition. We conclude that in healthy Europeans, age per se is not a significant cause of insulin resistance of glucose metabolism or lipolysis.