Productivity, water-use efficiency and tolerance to moderate water deficit correlate in 33 poplar genotypes from a Populus deltoides x Populus trichocarpa F1 progeny

Genotypic variability for productivity, water-use efficiency and leaf traits in 33 genotypes selected from an F1 progeny of Populus deltoides Bartr. ex Marsh x Populus trichocarpa L. was explored under optimal and moderate water-deficit conditions. Saplings of the 33 genotypes were grown in a two-plot open field at INRA Orléans (France) and coppiced every year. A moderate water deficit was induced during two successive years on one plot by withholding irrigation, while the second one remained irrigated (control). Stem biomass and leaf structure (e.g., specific leaf area and leaf area) were measured in 2004 and 2005 and functional leaf traits (e.g., carbon isotope discrimination, Delta) were measured only in 2004. Tolerance to water deficit was estimated at genotype level as the ability to limit losses in biomass production in water deficit versus control trees. Stem biomass, leaf structure and Delta displayed a significant genotypic variability whatever the irrigation regime. For all traits, genotype ranks remained stable across years for similar irrigation conditions. Carbon isotope discrimination scaled negatively with productivity and leaf nitrogen content in controls. The most productive genotypes were the least tolerant to moderate water deficit. No relationship was evidenced between Delta and the level of tolerance to water deficit. The relationships between traits evidenced in this collection of P. deltoides x P. trichocarpa F1 genotypes contrast with the ones that were previously detected in a collection of P. deltoides x Populus nigra L. cultivars tested in the same field trial.

[An aortic insufficiency diagnosed under cabergoline]

We report the case of a restrictive aortic insufficiency diagnosed on a 53-year old woman while being treated by low dose of cabergoline for hyperprolactinemia. Such valves involvements had already been described with cabergoline and other dopamine agonists, drugs the patient was previously exposed to. However, chronology of events leads us to suspect cabergoline, although such effects had only been described with much higher doses. This case may recommend to perform echocardiograms upon patients treated by cabergoline, and probably such a caution may be enforced in patients previously exposed to other dopamine agonists. On another hand, the diagnostic of a restrictive valvulopathy may lead to suspect a iatrogenic origin including dopamine agonists.

Specific phenotype associated with diabetes mellitus secondary to chronic hepatitis C infection

AIM

A link between chronic hepatitis C virus (HCV) infection, Type 2 diabetes mellitus and insulin resistance has been suggested by several studies. However, HCV infection appears to be associated with insulin resistance but not with the metabolic syndrome. The aim of this study was to determine whether chronic HCV infection had an impact on the clinical characteristics of Type 2 diabetes.

METHODS

We studied retrospectively a group of patients with diabetes mellitus associated with HCV infection (HCV-DM) and compared them with patients with conventional Type 2 diabetes (DM).

RESULTS

The HCV-DM patients had a lower body mass index (P = 0.001) and systolic blood pressure (P = 0.04) compared with patients with DM diabetes. Ten patients (27.0%) in the HCV-DM group and 35 (47.3%) in the DM group had microalbuminuria (P = 0.04). DM patients had significantly higher serum creatinine levels than HCV-DM patients [87 (72-108) vs. 77 (64-86) micromol/l, P = 0.02; median (interquartile range)] but creatinine clearance (Cockroft Gault calculation) was similar. One HCV-DM patient (2.7%) and 44 DM patients (59.4%) were treated with hypolipidaemic therapy (P = 0.0001). Even although nearly two-thirds of the overall DM group were prescribed cholesterol-lowering drugs, DM patients had significantly higher total cholesterol, high-density lipoprotein cholesterol and triglyceride levels than HCV-DM patients.

CONCLUSION

Our study provides further evidence that HCV-DM patients have specific clinical characteristics in comparison with classical DM patients. These data suggest an association between HCV virus infection and the development of insulin resistance or diabetes mellitus without the typical features of the metabolic syndrome.

Effects of 20 mg rosuvastatin on VLDL1-, VLDL2-, IDL- and LDL-ApoB kinetics in type 2 diabetes

AIMS/HYPOTHESIS

In addition to its efficacy in reducing LDL-cholesterol, rosuvastatin has been shown to significantly decrease plasma triacylglycerol. The use of rosuvastatin may be beneficial in patients with type 2 diabetes, who usually have increased triacylglycerol levels. However, its effects on the metabolism of triacylglycerol-rich lipoproteins in type 2 diabetic patients remains unknown.

METHODS

We performed a randomised double-blind crossover trial of 6-week treatment with placebo or rosuvastatin 20 mg in eight patients with type 2 diabetes who were being treated with oral glucose-lowering agents. In each patient, an in vivo kinetic study of apolipoprotein B (ApoB)-containing lipoproteins with [13C]leucine was performed at the end of each treatment period. A central randomisation centre used computer-generated tables to allocate treatments. Participants, caregivers and those assessing the outcomes were blinded to group assignment.

RESULTS

Rosuvastatin 20 mg significantly reduced plasma LDL-cholesterol, triacylglycerol and total ApoB. It also significantly reduced ApoB pool sizes of larger triacylglycerol-rich VLDL particles (VLDL1; p = 0.011), smaller VLDL particles (VLDL2; p = 0.011), intermediate density lipoprotein (IDL; p = 0.011) and LDL (p = 0.011). This reduction was associated with a significant increase in the total fractional catabolic rate of VLDL1-ApoB (6.70 +/- 3.24 vs 4.52 +/- 2.34 pool/day, p = 0.049), VLDL2-ApoB (8.72 +/- 3.37 vs 5.36 +/- 2.64, p = 0.011), IDL-ApoB (7.06 +/- 1.68 vs 4.21 +/- 1.51, p = 0.011) and LDL-ApoB (1.02 +/- 0.27 vs 0.59 +/- 0.13, p = 0.011). Rosuvastatin did not change the production rates of VLDL2-, IDL- or LDL-, but did reduce VLDL1-ApoB production rate (12.4 +/- 4.5 vs 19.5 +/- 8.4 mg kg(-1) day(-1), p = 0.035). No side effects of rosuvastatin were observed during the study.

CONCLUSIONS/INTERPRETATION

In type 2 diabetic patients rosuvastatin 20 mg not only induces a significant increase of LDL-ApoB catabolism (73%), but also has favourable effects on the catabolism of triacylglycerol-rich lipoproteins, e.g. a significant increase in the catabolism of VLDL1-ApoB (48%), VLDL2-ApoB (63%) and IDL-ApoB (68%), and a reduction in the production rate of VLDL1-ApoB (-36%). The effects of rosuvastatin on the metabolism of triacylglycerol-rich lipoproteins may be beneficial for prevention of atherosclerosis in type 2 diabetic patients.

Distinct patterns of heparin affinity chromatography VLDL1 and VLDL2 subfractions in the different dyslipidaemias

Very low density lipoprotein (VLDL) 1 and 2 were fractionated by heparin affinity chromatography into a bound and an unbound fraction and the different subfractions were quantified in 17 normolipidaemic (NL), 13 hypercholesterolaemic (HC), 10 hypertriglyceridaemic (HTG) and 11 combined hyperlipidaemic subjects (CHL). Unbound VLDL1 and VLDL2 were, respectively, 1.9- and 2.2-fold richer in triglycerides than bound VLDL1 and VLDL2. In HTG and CHL the concentration of all the VLDL subfractions was increased and plasma triglyceride level was correlated to unbound VLDL1 and to bound VLDL1 (respectively, r=0.86 (p<0.001) and r=0.77 (p<0.01) in HTG and r=0.73 (p<0.001) and r=0.62 (p<0.05) in CHL). In HC unbound VLDL2 and bound VLDL2 concentration were increased compared to NL and in CHL, the concentration of bound VLDL2 was particularly increased (3.2-fold compared to NL (p<0.001)). In both HC and CHL bound VLDL2 concentration was correlated to low density lipoprotein cholesterol (LDL-C) concentration (respectively, r=0.67 (p<0.01) and r=0.62 (p<0.05)). In hypertriglyceridaemic states the intravascular accumulation of both unbound and bound VLDL1 appears as the determinant of plasma triglyceride concentration, whereas in moderately hypercholesterolaemic states the concentration of bound VLDL2 is strikingly correlated to LDL-C concentration, suggesting that these two species are linked metabolically, e.g. bound VLDL2 contain the precursor pool of LDL.

[Aortic insufficiency under weak doses of cabergoline for non-tumoral hyperprolactinemia]

Used in its neurological indication, cabergoline is known to induce cardiac valve regurgitations, essentially mitral and aortic valvular diseases, by its action on the 5HT2b receptors. Until now, it was assumed that the dose and the duration of exposure were the major factors of appearance. We describe a case of aortic insufficiency which developed in a patient given low doses of cabergoline (0.5 mg weekly) for non-tumoral hyperprolactinemia. Because of previous use of appetite suppressants and of bromocriptine, the exclusive responsibility of cabergoline remained uncertain. The potential gravity of these valvular heart diseases emphasizes the importance of careful cardiologic examination before and during treatment.

Effect of insulin treatment on plasma oxidized LDL/LDL-cholesterol ratio in type 2 diabetic patients

OBJECTIVE

In type 2 diabetes mellitus, oxidized LDL/LDL-Cholesterol ratio, an accurate estimation of in vivo LDL oxidation, has been reported elevated and associated with macrovascular disease. Because insulin therapy induces significant modification of lipid metabolism, in type 2 diabetes, we evaluated the effect of insulin treatment on oxidized LDL/LDL-C ratio in type 2 diabetic patients and analyzed the results in comparison with the modifications induced by insulin on glycaemia, plasma lipids and LDL receptors.

RESEARCH DESIGN AND METHODS

Plasma oxidized LDL concentrations were measured by sandwich ELISA in 21 type 2 diabetic patients before and 3 months after the introduction of insulin therapy, and in 27 age-matched controls.

RESULTS

Type 2 diabetic patients had, compared to controls, significantly increased oxidized LDL/LDL-C ratio (P<0.0001). Three months after insulin treatment, oxidized LDL/LDL-C ratio was significantly reduced (21.1+/-4.7 vs. 24.0+/-5.8 U/mmol, P<0.01). This reduction was strongly associated, in multivariate analysis, with reduction of LDL(TG/cholesterol ratio) (P=0.008), and to a lesser extent with the decrease of LDL fructosamine (P=0.034), but not with the increase of the number of LDL receptors.

CONCLUSIONS

In the present study we demonstrate for the first time a lowering effect of insulin therapy on oxidized LDL/LDL-C ratio in type 2 diabetic patients. This decrease is mainly associated with the reduction of LDL TG-enrichment, and to a lesser extent with the decrease of LDL glycation, but not with the insulin-induced increase in number of LDL receptors.

Normal metabolism of apolipoprotein B100-containing lipoproteins despite qualitative abnormalities in type 1 diabetic men

AIMS/HYPOTHESIS

Type 1 diabetic subjects are at increased risk of cardiovascular disease and exhibit multiple qualitative abnormalities of apolipoprotein (apo) B100-containing lipoproteins. This stable isotope kinetic experiment was designed to study whether these abnormalities are associated with changes in the synthesis and fractional catabolic rates of VLDL-, IDL- and LDL-apoB100.

METHODS

Using a bolus followed by a 16-h constant infusion of 13C-leucine, we performed a kinetic study in eight men with type 1 diabetes treated with a continuous subcutaneous insulin infusion administered by an external pump and in seven healthy men, in the fed state.

RESULTS

The mean HbA1c level in the type 1 diabetic patients was 8.00+/-1.48%. Plasma triglyceride, and total, LDL and HDL cholesterol levels were similar in patients and control subjects. VLDL were less triglyceride rich in type 1 diabetic patients than in control subjects (VLDL triglyceride : apoB 6.91+/-0.81 vs 8.29+/-1.24 mmol/g, p=0.05). Conversely, the IDL and LDL of the type 1 diabetic patients contained relatively higher levels of triglycerides (IDL triglycerides : apoB 2.16+/-0.36 vs 1.57+/-0.30 mmol/g, p<0.01; LDL triglycerides : apoB 0.27+/-0.06 vs 0.16+/-0.04 mmol/g, p<0.05). The apoB100 pool size, production and fractional catabolic rates in the two groups of subjects were similar for all lipoprotein fractions.

CONCLUSIONS/INTERPRETATION

Despite qualitative abnormalities, especially abnormalities of triglyceride content, the metabolism of apoB100-containing lipoproteins is not altered in type 1 diabetic men with fair glycaemic control with continuous subcutaneous insulin infusion. The high risk of atherosclerosis in these patients cannot be explained by kinetic abnormalities of apoB100-containing lipoproteins.

Étude des atteintes de la surface oculaire chez les patients diabétiques

INTRODUCTION

Diabetes mellitus leads to microvascular complications and altered basement membranes, which are partly responsible for ocular complications. Corneal nerve impairment is involved in ocular surface disease as well. We examined the possible relation between ocular surface signs and retinal or neuronal degenerative complications due to diabetes.

PATIENTS AND METHODS

Diabetics and control subjects were compared for corneal sensitivity and tear function parameters such as the Schirmer test, tear film break-up time (BUT), and fluorescein and lissamine green stainings. The relation of the duration of the disease, the stage of retinopathy, metabolic control (HbA1c), and diabetic peripheral neuropathy with ocular surface disorders were noted.

RESULTS

Twelve healthy patients were compared to 48 diabetics. The Schirmer test value, BUT, and fluorescein and lissamine green impregnations were significantly modified in diabetics compared to controls (p<0.0001), with no relation to the duration of the disease or metabolic control. The mean corneal sensitivity was significantly lower in diabetic patients (p<0.01), diabetics with peripheral neuropathy (p=0.00008), and diabetics with preproliferative retinopathy (p=0.0003). Tear function parameters were more frequently altered in patients presenting preproliferative retinopathy and peripheral neuropathy (p<0.001).

CONCLUSIONS

Diabetes can lead to ocular surface impairments with qualitative and quantitative tear disorders, all of which seem to evolve in close relation with retinopathy and peripheral neuropathy. These lacrymal and corneoconjunctival abnormalities, even if not currently mentioned by diabetic patients, can result in severe neurotrophic complications.

High circulating levels of 7beta- and 7alpha-hydroxycholesterol and presence of apoptotic and oxidative markers in arterial lesions of normocholesterolemic atherosclerotic patients undergoing endarterectomy

In previous investigations, we found that 7beta-hydroxycholesterol had potent pro-apoptotic, and pro-oxidative properties. So, we asked whether the circulating level of this oxysterol was enhanced in atherosclerotic patients undergoing endarterectomy of the superficial femoral artery. To this end, 7beta-hydroxycholesterol serum concentrations were determined and compared with common lipid parameters in atherosclerotic patients, and in healthy subjects. 7alpha-hydroxycholesterol was simultaneously measured to evaluate the reliability of the method used for oxysterol analysis. On normal and atherosclerotic arterial fragments from patients, markers of oxidation (4-hydroxynonenal (4-HNE) adducts), and apoptosis (activated caspase-3; condensed/fragmented nuclei) were studied. Interestingly, high serum concentrations of 7beta- and 7alpha-hydroxycholesterol were found in normocholesterolemic atherosclerotic patients. However, in statin-treated patients, the circulating levels of 7beta- and 7alpha-hydroxycholesterol tend towards normal values. Therefore, 7beta- as well as 7alpha-hydroxycholesterol could be more appropriate markers of lipid metabolism disorders than cholesterol or LDL in normocholesterolemic patients with atherosclerosis of the lower limbs, and statins could normalize their serum concentrations. At the arterial level, apoptotic cells were mainly identified in low grade lesions and no statin effects were found on oxidation and apoptosis.

Serum adiponectin and metabolic parameters in HIV-1-infected patients after substitution of nevirapine for protease inhibitors

BACKGROUND

In the context of HIV infection and antiretroviral therapy, adiponectin concentrations have been shown to be related to lipodystrophy, metabolic alterations and HIV-protease inhibitor (PI) use. The replacement of PI by nevirapine has improved the lipid profile of patients under antiretroviral therapy. The aim of the present study was to examine whether adiponectin concentration or insulin sensitivity level correlate with the modifications of lipid parameters after the switch of PI by nevirapine.

MATERIAL AND METHODS

The evolution of metabolic parameters before and after 6 months of substitution of nevirapine for protease inhibitors was evaluated in a cohort of 55 HIV-1 infected patients. Adiponectin concentration, insulin sensitivity, lipid profile, cholesterol ester transfer protein (CETP) mass concentration and triglyceride enrichment of HDL were determined before and after the replacement of PI by nevirapine. Insulin sensitivity was evaluated by the HOMA model assessment.

RESULTS

Twenty-four weeks of treatment with nevirapine improved significantly the lipid profile with a significant reduction of apoB (from 0.98 to 0.92 g L(-1); P = 0.005) and triglyceride (from 2.02 to 1.66 mmol L(-1); P = 0.02). HDL cholesterol and apoA1 increased significantly (from 0.99 to 1.19 mmol L(-1); P = 0.001 and from 1.40 to 1.57 g L(-1); P < 0.001, respectively). The triglyceride enrichment of HDL significantly decreased after the replacement of PI by nevirapine (from 0.248 +/- 0.092 to 0.213 +/- 0.093; P = 0.003). At baseline, and after 24 weeks of nevirapine treatment, we observed significant correlations between adiponectin level and lipid parameters [(HDL-cholesterol (r = 0.66, P = 0.001 and r = 0.69, P = 0.001); triglycerides (r = -0.42, P = 0.002 and r = -0.57, P = 0.001), and triglyceride enrichment of HDL (r = -0.43, P = 0.005 and r = -0.53, P = 0.005)]. Twenty-four weeks of treatment with nevirapine did not significantly change adiponectin concentrations (from 984 to 1086 micro g L(-1), P = 0.22), CETP mass and insulin sensitivity.

CONCLUSION

This study shows that even though a strong correlation was found between adiponectin and some metabolic parameters at baseline and after 24 weeks of treatment by nevirapine, the improvement of lipid profile observed after the replacement of PI by nevirapine was not in relation to the change of plasma adiponectin concentration. The significant decrease of triglyceride enrichment of HDL after the replacement of PI by nevirapine probably leads to a decreased catabolism of HDL lipoprotein, and consequently explains the increase of plasma HDL concentration observed in this study.

[Is there an increased risk for cardiovascular disease in HIV-infected patients on antiretroviral therapy?]

There is a growing concern about an increased risk for cardiovascular disease in HIV infected patients receiving antiretroviral therapy (ART). This risk could be related to metabolic abnormalities associated with long-term use of antiretroviral drugs. In fact, well recognized cardiovascular risk factors such as hypertension, dyslipidaemia, diabetes mellitus and central fat deposition are increasingly seen in HIV patients on ART. These factors can also be associated with non reversible risk factors, such as male sex, age greater than 40 years and family history of premature coronary artery disease. In addition, cigarette smoking and sedentary lifestyle may predispose these patients to significant cardiovascular disease. A direct atherogenic effect of HIV infection itself or antiretroviral drugs is unlikely. Epidemiological studies have suggested an increased risk for coronary artery disease in HIV infected persons; nevertheless, only long term follow-up could confirm this statement. Despite these uncertainties, it seems reasonable to identify and manage cardiovascular risk factors in HIV infected patients.

Distribution of Aquaporin 9 in the adult rat brain: Preferential expression in catecholaminergic neurons and in glial cells

Aquaporin 9 (AQP9) is a recently cloned water channel that is permeable to monocarboxylate, glycerol and urea. In rat, AQP9 has been found in testis and liver as well as in brain where its expression has been initially shown in glial cells in forebrain. However, the expression of AQP9 has not been investigated in the brainstem. The purpose of this study is to describe the distribution of AQP9-immunoreactive cells throughout the adult rat brain using reverse transcriptase-polymerase chain reaction (RT-PCR), Western blot and immunohistochemistry. We performed immunolabeling on brain from animals perfused with fixative and we show that AQP9 is expressed (i) in astrocytes in the glia limitans, in the white matter and in glial cells of the cerebellum, (ii) in the endothelial cells of pial vessels, and (iii) in specific groups of neurons. The neuronal AQP9 expression was almost exclusively observed in catecholaminergic cells including the adrenergic, noradrenergic and dopaminergic groups, but not in other monoaminergic neurons such as serotonergic or histaminergic cells. A slight labeling was also observed in non-catecholaminergic neurons localized in the paraventricular nucleus of the hypothalamus. These results indicate that AQP9 has a unique brain distribution with a preferential localization in catecholaminergic nuclei known to be involved in many cerebral functions. While the presence of AQP9 in glia limitans and in endothelial cells of the pial vessels could be related to water transport through the blood-brain barrier, its expression in neuronal cells, not directly involved in the osmoregulation, suggests that brain AQP9 could also be used as a metabolite channel since lactate and glycerol can be energy substrates for neurons.

Microstructure and dynamics near an attractive colloidal glass transition

The microstructure and dynamics of a colloidal system interacting via short-ranged interparticle potential is studied by ultra-small-angle x-ray scattering and x-ray photon correlation spectroscopy. A colloidal gas-liquid type transition is induced when the short-ranged attractive interactions attain sufficient magnitude. The development of liquidlike structure is preceded by a systematic transition in the particle dynamics from diffusive to constrained motion and then completely frozen behavior. This demonstrates the existence of a jamming transition induced by strong short-ranged attractive interactions even at low packing fractions.

LDL-receptors expression in HIV-infected patients: relations to antiretroviral therapy, hormonal status, and presence of lipodystrophy

BACKGROUND

Abnormalities in lipid levels and lipodystrophy (LD) have been commonly reported after commencement of highly active antiretroviral therapy (HAART). A major mechanism by which plasma low-density lipoprotein (LDL) cholesterol levels may be influenced is via the regulation of hepatic LDL receptor expression. The activity of LDL receptors is under hormonal control. Moreover, HIV infection and HAART are associated with important modifications of hormonal status. As the cause of these adverse reactions is unknown, the effects of HAART and lipodystrophy on LDL receptors were evaluated.

MATERIALS AND METHODS

Thirty-nine HIV treated patients (21 with a protease inhibitor (PI) containing regimen, 18 without PI use) and 22 control subjects were tested for insulin resistance (HOMA model assessment), lipid profile, serum concentration of dehydroepiandrosterone (DHEA) and LDL-R expression. LDL-R on mononuclear cells were quantified by flow cytrometry.

RESULTS

Among the 39 HIV infected patients, 14 patients had a lipodystrophy (LD). Patients with LD had significantly higher levels of triglyceride (TG) and insulin resistance compared to patients without LD. There was no significant difference in LDL-R count between patients with or without PI use. In contrast, LDL-R count was significantly lower in patients with LD compared with those without (8504 +/- 3901 vs. 13 200 +/- 4532, P = 0.001). There was no difference in LDL-R count between patients without LD and control subjects. Patients with LD had lower levels of DHEA compared to patients without LD. In HIV-infected patients, we found a significant correlation between LDL-R expression and TG (r = -0.32; P = 0.04) and LDL cholesterol (r = -0.33; P = 0.04). In contrast, we did not observe a correlation between DHEA level and LDL-R count or LDL cholesterol level.

CONCLUSIONS

HIV-lipodystrophy is associated with a lower expression of LDL-R. This decreased expression of LDL-R seems independent of DHEA or insulin secretion.

Incidence of gynecomastia in men infected with HIV and treated with highly active antiretroviral therapy

A longitudinal study found that the incidence of gynecomastia in HIV-infected male patients treated with highly active antiretroviral therapy was 0.8/100 patient-years, with a prevalence of 2.8% in those treated for > or = 2 y. Even though the physiopathology remains unclear, this study suggests that gynecomastia should be monitored in these patients.

Organization of the bovine alpha 2-fucosyltransferase gene cluster suggests that the Sec1 gene might have been shaped through a nonautonomous L1-retrotransposition event within the same locus

By referring to the split coding sequence of the highly conserved alpha 6-fucosyltransferase gene family (assumed to be representative of the common alpha 2 and alpha 6 fucosyltransferase gene ancestor), we have hypothesized that the monoexonic coding sequences of the present alpha 2-fucosyltransferase genes have been shaped in mammals by several events of retrotransposition and/or duplication. In order to test our hypothesis, we determined the structure of the three bovine alpha 2-fucosyltransferase genes (bfut1, bfut2, and sec1) and analyzed their characteristics compared with their human counterparts (FUT1, FUT2, and Sec1). We show that in mammals, a complex nonautonomous L1-retrotransposition event occurred within the locus of the alpha 2-fucosyltransferase ancestor gene itself. A consequence of this event was the processing in Catarrhini of a Sec1 pseudogene via several point mutations.

Structure and differential expression of the four members of the Arabidopsis thaliana ferritin gene family

Four ferritin genes are found within the complete sequence of the Arabidopsis thaliana genome. All of them are expressed and their corresponding cDNA species have been cloned. The polypeptide sequences deduced from these four genes confirm all the properties of the ferritin subunits described so far, non-exhaustively, from various plant species. All are predicted to be targeted to the plastids, which is consistent with the existence of a putative transit peptide at their N-terminal extremity. They also all possess a conserved extension peptide in the mature subunit. Specific residues for ferroxidase activity and iron nucleation, which are found respectively in H-type or L-type ferritin subunits in animals, are both conserved within each of the four A. thaliana ferritin polypeptides. In addition, the hydrophilic nature of the plant ferritin E-helix is conserved in the four A. thaliana ferritin subunits. Besides this strong structural conservation, the four genes are differentially expressed in response to various environmental signals, and during the course of plant growth and development. AtFer1 and AtFer3 are the two major genes expressed in response to treatment with an iron overload. Under our experimental conditions, AtFer4 is expressed with different kinetics and AtFer2 is not responsive to iron. H(2)O(2) activates the expression of AtFer1 and, to a smaller extent, AtFer3. Abscisic acid promotes the expression of only AtFer2, which is consistent with the observation that this is the only gene of the four to be expressed in seeds, whereas AtFer1, AtFer4 and AtFer3 are expressed in various vegetative organs but not in seeds.

Risk factors for diabetes mellitus and early insulin resistance in chronic hepatitis C

BACKGROUND/AIMS

Our aims were to investigate the host and viral specific factors associated with diabetes mellitus (DM) and insulin resistance in chronic hepatitis C patients.

METHODS

One hundred and three hepatitis C virus (HCV)-infected were studied to assess the effects of HCV genotype, hepatic iron content, steatosis, hepatic fibrosis, body mass index (BMI) and family history of DM on the occurrence of DM. Insulin resistance (HOMA IR) was studied in 81 non-diabetic patients to determine the mechanism associated with insulin resistance in this subgroup.

RESULTS

Sixteen of the 123 were diabetic (13.0%). The variables predictive of DM were METAVIR fibrosis score 4 (OR, 13.16; P = 0.012), family history of diabetes (OR, 16.2; P = 0.0023), BMI (OR, 1.37; P = 0.017) and age (OR, 1.09; P = 0.002). In non-diabetic HCV-infected patients, HOMA-IR of METAVIR fibrosis score 0 and 1 patients were significantly different than score 2 and score 3/4 patients.

CONCLUSIONS

Our findings indicate that older age, obesity, severe liver fibrosis and family history of diabetes help identify those HCV patients who might have potential risk factors for development of DM. We observed that insulin resistance in non-diabetic HCV-infected patients was related to grading of liver fibrosis, and occurs already at an early stage in the course of HCV infection.

Discovery of 12 satellites of Saturn exhibiting orbital clustering

The giant planets in the Solar System each have two groups of satellites. The regular satellites move along nearly circular orbits in the planet's orbital plane, revolving about it in the same sense as the planet spins. In contrast, the so-called irregular satellites are generally smaller in size and are characterized by large orbits with significant eccentricity, inclination or both. The differences in their characteristics suggest that the regular and irregular satellites formed by different mechanisms: the regular satellites are believed to have formed in an accretion disk around the planet, like a miniature Solar System, whereas the irregulars are generally thought to be captured planetesimals. Here we report the discovery of 12 irregular satellites of Saturn, along with the determinations of their orbits. These orbits, along with the orbits of irregular satellites of Jupiter and Uranus, fall into groups on the basis of their orbital inclinations. We interpret this result as indicating that most of the irregular moons are collisional remnants of larger satellites that were fragmented after capture, rather than being captured independently.

Association between insulin resistance and hepatitis C virus chronic infection in HIV-hepatitis C virus-coinfected patients undergoing antiretroviral therapy

Insulin resistance (IR) in the context of highly active antiretroviral therapy (HAART) is becoming more common in HIV-infected patients. Patients with chronic hepatitis C virus (HCV) infection have an increased risk of IR and type 2 diabetes mellitus. A cross-sectional study was performed to investigate whether chronic HCV infection constitutes a risk factor for IR in HIV-HCV-coinfected patients undergoing HAART. Inclusion criteria were positive HCV viremia and a sustained increase of alanine aminotransferase of at least twice the normal value. A total of 29 HIV-HCV patients, 76 HIV patients, and 121 HCV controls were tested for IR and body mass index (BMI). IR was measured using the homeostasis model assessment. In HIV-HCV and HIV patients, fat redistribution and lipid profile were assessed. There was no significant difference in age, CD4 cell count, HIV viral load, or duration of HAART between the HIV-HCV and HIV groups. HIV-HCV patients and HCV controls had a significant increase in IR when compared with HIV patients (0.25 +/- 0.28 and 0.21 +/- 0.34 versus 0.04 +/- 0.37; p =.01 and p =.003, respectively). Lipoatrophy was observed more frequently in HIV-HCV patients in comparison with HIV patients (41% versus 14%; p =.003). In HIV-HCV patients, total cholesterol and triglyceride levels were significantly lower than in HIV patients. In multivariate analysis, IR, BMI, triglyceride levels, and peripheral fat wasting were the independent variables associated with HCV infection. Our findings suggest that chronic HCV infection is a significant factor associated with the development of metabolic abnormalities and with modifications in body composition in HIV patients receiving antiretroviral treatment.

[Blood lipid abnormalities during treatment with protease inhibitors]

HYPERLIPIDEMIA: HIV-1 protease-inhibitors therapy is associated with increased levels of triglycerides, LDL-cholesterol and Lp(a). But the understanding of hyperlipidaemia occurring in patients treated with HIV-1 protease-inhibitors is not easy since HIV infection itself is associated with lipid abnormalities and since HIV-1 protease-inhibitors therapy is also responsible for the development of a lipodystrophy syndrome (insulin resistance) which may influence lipid metabolism. However, many data indicate that HIV-1 protease-inhibitors therapy itself modifies significantly lipid metabolism.

UNDERLYING MECHANISMS

The mechanisms involved in HIV-1 protease-inhibitors induced hyperlipidaemia are still unclear. HIV-1 protease-inhibitors could bind to LRP (Low density lipoprotein receptor Related Protein), impairing hepatic chylomicron-remnants and VLDL uptake. They could interact with the retinoid X receptor (RXR), which functions as a heterodimer with PPAR (Peroxisome Proliferator Activator Receptor). HIV-1 protease-inhibitors could also modify lipoprotein metabolism through cytokines.