Decaprenylphosphoryl-β-D-ribose 2'-epimerase from Mycobacterium tuberculosis is a magic drug target

Tuberculosis is still a leading cause of death in developing countries and a resurgent disease in developed countries. The selection and soaring spread of Mycobacterium tuberculosis multidrug-resistant (MDR-TB) and extensively drug-resistant strains (XDR-TB) is a severe public health problem. Currently, there is an urgent need of new drugs for tuberculosis treatment, with novel mechanisms of action and, moreover, the necessity to identify new drug targets. Several enzymes involved in various metabolic processes have been described as potential targets for the development of new drugs. Recently, two different classes of most promising drugs, the benzothiazinones (BTZ) and the dinitrobenzamide derivatives (DNB), have been found to be highly active against M. tuberculosis, including XDR-TB strains. Interestingly, both drugs have the same target: the heteromeric decaprenylphosphoryl-β-D-ribose 2'-epimerase encoded by dprE1 (Rv3790) and dprE2 (Rv3791) genes, respectively. DprE1 and DprE2 are involved in the biosynthesis of D-arabinose and, in particular, they are essential to perform the transformation of decaprenylphosphoryl-D-ribose to decaprenylphosphoryl-D-arabinose, which is a substrate for arabinosyltransferases in the synthesis of the cell-envelope arabinogalactan and liporabinomannan polysaccharides of mycobacteria. Arabinogalactan is a fundamental component of the mycobacterial cell wall, which covalently binds the outer layer of mycolic acids to peptidoglycan. The heteromeric decaprenylphosphoryl-β-D-ribose 2'-epimerase thus represents a valid vulnerable antimycobacterial drug target which could result in "magic" for tuberculosis treatment.

Coronary vasoreactivity is not altered in young people with type 1 diabetes

BACKGROUND AND AIM

Abnormal coronary microvascular circulation has been demonstrated in diabetes and is associated with increased rate of cardiovascular events. Our objective was to evaluate coronary vasoreactivity in young people with type 1 diabetes with and without microvascular complications.

METHODS AND RESULTS

Twenty-five type 1 diabetic patients without microvascular complications (DC-), 23 with microvascular complications (DC+), and 18 control subjects (C) were studied. Coronary vasoreactivity was assessed by means of coronary flow reserve (CFR). Blood flow velocity in the left anterior descending coronary artery was measured at rest and after high-dose dipyridamole using transthoracic color-guided pulsed Doppler echocardiography. CFR was defined as the ratio of hyperaemic to resting diastolic peak flow velocities. The three groups had similar cardiac function parameters, and also systolic and diastolic blood pressure at rest, which remained unchanged during dipyridamole infusion. Resting coronary flow velocity was comparable in C, DC-, and DC+ (p=ns). Dipyridamole infusion produced a threefold increase in coronary diastolic peak velocity, which reached similar values in C (0.69±0.16 m/s), DC- (0.69±0.18 m/s), and DC+ (0.66±0.11 m/s). Mean CFR ratio was similar in C (3.33±0.66), DC- (3.30±0.51), and DC+ (3.24±0.60). At multiple linear regression analysis, no association was found between CFR and age, sex, HbA(1c), duration of diabetes, and complications.

CONCLUSION

Coronary vasodilatory function is preserved in young D patients, even those with early microvascular complications, suggesting that coronary vasoreactivity deteriorates at more advanced stages of microvascular complications and/or in the presence of other cardiovascular risk factors.

Cardiovascular risk in women with diabetes

Women with diabetes have a high risk of cardiovascular disease that, almost completely eliminates the gender difference in cardiovascular morbidity and mortality between non-diabetic men and women. In this chapter we have reviewed data showing that cardiovascular risk factors are more common, more likely to cluster, or more severe in diabetic women than men; this may be due to biological or behavioural factors. Disparities in accessibility, quality and, possibly, effectiveness of care further disadvantage diabetic women. Based on available data it can be concluded that a large number of CVD deaths are preventable in diabetic women; therefore special attention should be paid to risk factors detection and correction, as well as timely CHD diagnosis and treatment in diabetic women. To meet these needs gender specific guidelines and implementation measures may be in order.

Effects of the regular consumption of wholemeal wheat foods on cardiovascular risk factors in healthy people

BACKGROUND AND AIM

The intake of wholemeal foods is consistently associated with reduced risk of type 2 diabetes and cardiovascular diseases in epidemiological studies, although the mechanisms of this association are unclear. Here we aim to compare in healthy subjects the metabolic effects of a diet rich in wholemeal wheat foods versus one based on the same products in refined form.

METHODS AND RESULTS

Fifteen healthy individuals (12 M/3 F), mean age 54.5+/-7.6 years, BMI 27.4+/-3.0 kg/m(2) (mean+/-SD), participated in a randomized sequential crossover study. After 2 weeks run-in, participants were randomly assigned to two isoenergetic diets with similar macronutrient composition, one rich in wholemeal wheat foods and the other with the same foods but in refined form (cereal fibre 23.1 vs. 9.8 g/day). After the two treatment periods (each lasting 3 weeks) plasma glucose and lipid metabolism, antioxidant activity, acetic acid, magnesium, adipokines, incretins and high-sensitivity C-reactive protein (hs-CRP) were measured at fasting and for 4h after a standard test meal (kcal 1103, protein 12%, CHO 53%, fat 35%) based on wholemeal or refined wheat foods, respectively. After the two diets there were no differences in fasting nor in postprandial plasma parameter responses; only glucose was slightly but significantly lower at 240 min after the refined wheat food meal compared to the wholemeal wheat food meal. Conversely, after the wholemeal diet both total (-4.3%; p<0.03) and LDL (-4.9%; p<0.04) cholesterol levels were lower than after the refined wheat diet at fasting.

CONCLUSIONS

Consumption of wholemeal wheat foods for 3 weeks reduces significantly fasting plasma cholesterol as well as LDL cholesterol levels in healthy individuals without major effects on glucose and insulin metabolism, antioxidant status and sub-clinical inflammation markers.

Lower fasting blood glucose, glucose variability and nocturnal hypoglycaemia with glargine vs NPH basal insulin in subjects with Type 1 diabetes

BACKGROUND AND AIMS

To compare switching from NPH insulin (NPH) to insulin glargine (glargine) with continuing NPH for changes in fasting blood glucose (FBG) in patients with Type 1 diabetes on basal-bolus therapy with insulin lispro as bolus insulin. Secondary objectives included self-monitoring blood glucose, mean daily blood glucose (MDBG) and mean amplitude glucose excursion (MAGE) values alongside changes in HbA(1c) and safety profiles.

METHODS AND RESULTS

This was a 30-week, parallel, open-label, multicentre study. Seven-point profiles were used to calculate MDBG and MAGE. Hypoglycaemia and adverse events were recorded by participants. FBG improved significantly with both glargine (baseline-endpoint change: -28.0 mg/dL; 95% CI: -37.3, -18.7 mg/dL; p<0.001) and NPH (-9.8 mg/dL; 95% CI: -19.1, -0.5 mg/dL; p=0.0374). The improvement was significantly greater with glargine than NPH (mean difference: -18.2 mg/dL; 95% CI: -31.3, -5.2 mg/dL; p=0.0064). MDBG (-10.1 mg/dL; 95% CI: -18.1, -2.1 mg/dL; p=0.0126) and MAGE (-20.0 mg/dL; 95% CI: -34.5, -5.9 mg/dL; p=0.0056) decreased significantly with glargine, but not NPH although endpoint values were no different with the two insulins. Baseline to endpoint change in HbA(1c) was similar (-0.56 vs -0.56%) with no differences at endpoint. Overall hypoglycaemia was no different, but glargine reduced nocturnal hypoglycaemia ("serious episodes" with BG < 42 mg/dl, p=0.006) whereas NPH did not (p=0.123), although endpoint values were no different.

CONCLUSION

Switching from NPH to glargine is well tolerated and results into lower FBG, and lower glucose variability while reducing nocturnal hypoglycaemia. These data provide a rationale for more aggressive titration to target with glargine in Type 1 diabetes.

Precise measurement of the neutron magnetic form factor G(M)n in the few-GeV2 region

The neutron elastic magnetic form factor was extracted from quasielastic electron scattering on deuterium over the range Q;{2}=1.0-4.8 GeV2 with the CLAS detector at Jefferson Lab. High precision was achieved with a ratio technique and a simultaneous in situ calibration of the neutron detection efficiency. Neutrons were detected with electromagnetic calorimeters and time-of-flight scintillators at two beam energies. The dipole parametrization gives a good description of the data.

Serum apolipoproteins, lipoproteins and fatty acids in relation to ischaemic heart disease in northern and southern European males

Serum apolipoprotein and lipoprotein concentrations, fatty acid spectra of various lipids, dietary habits and common risk factors for ischaemic heart disease were studied in 73 and 77 randomly selected, 50-year-old healthy men in Naples and Stockholm, respectively. Mean serum cholesterol concentration was higher in Stockholm than in Naples men (6.23 vs. 5.47 mmol/l, p less than 0.001) as were low (LDL) (4.08 vs. 3.57 mmol/l, p less than 0.001) and high (HDL) (1.40 vs. 1.25 mmol/l, p less than 0.001) density lipoprotein fractions. Mean serum triglyceride concentrations did not differ. Mean apolipoprotein B and C-I concentrations were higher in Stockholm men (1,116 vs. 1,020 mg/l, p less than 0.05 and 96 vs. 79 mg/l, p less than 0.01, respectively). Stockholm men derived significantly more of their calories from fat (38 vs. 28%, p less than 0.001) and the dietary fat had significantly lower polyunsaturated-to-saturated fatty acid ratio (P/S-ratio 0.29 vs. 0.51, p less than 0.001), and less from carbohydrate (44 vs. 49%, p less than 0.001) than Naples men, respectively. Mean caloric intake and mean weight/height index did not differ. Stockholm men had higher blood pressures, but there were more smokers among Naples men. The higher fat intake in Stockholm men may offer an explanation of the differences seen in lipoprotein and apoprotein concentrations and compositions but other factors, such as genetic influences cannot be excluded. A greater cholesterol flux through the plasma compartment in Stockholm men may be one important factor contributing to the higher incidence of ischaemic heart disease in this population.

Search for the photoexcitation of exotic mesons in the pi+pi+pi- system

A search for exotic mesons in the pi;{+}pi;{+}pi;{-} system photoproduced by the charge exchange reaction gammap-->pi;{+}pi;{+}pi;{-}(n) was carried out by the CLAS Collaboration at Jefferson Lab. A tagged-photon beam with energies in the 4.8 to 5.4 GeV range, produced through bremsstrahlung from a 5.744 GeV electron beam, was incident on a liquid-hydrogen target. A partial wave analysis was performed on a sample of 83 000 events, the highest such statistics to date in this reaction at these energies. The main objective of this study was to look for the photoproduction of an exotic J;{PC}=1;{-+} resonant state in the 1 to 2 GeV mass range. Our partial wave analysis shows production of the a_{2}(1320) and the pi_{2}(1670) mesons, but no evidence for the a_{1}(1260), nor the pi_{1}(1600) exotic state at the expected levels. An upper limit of 13.5 nb is determined for the exotic pi_{1}(1600) cross section, less than 2% of the a_{2}(1320) production.

Measurement of direct f0(980) photoproduction on the proton

We report on the results of the first measurement of exclusive f_{0}(980) meson photoproduction on protons for E_{gamma}=3.0-3.8 GeV and -t=0.4-1.0 GeV2. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility. The resonance was detected via its decay in the pi;{+}pi;{-} channel by performing a partial wave analysis of the reaction gammap-->ppi;{+}pi;{-}. Clear evidence of the f_{0}(980) meson was found in the interference between P and S waves at M_{pi;{+}pi;{-}} approximately 1 GeV. The S-wave differential cross section integrated in the mass range of the f_{0}(980) was found to be a factor of about 50 smaller than the cross section for the rho meson. This is the first time the f_{0}(980) meson has been measured in a photoproduction experiment.

Myasthenia gravis in a patient affected by glycogen storage disease type Ib: a further manifestation of an increased risk for autoimmune disorders?

Glycogen storage disease type Ib (GSD Ib, OMIM 232220) is an inborn disorder of glucose metabolism, caused by mutations in the G6PT gene, encoding a glucose 6-phosphate transporter (G6PT). GSD Ib is mainly associated with fasting hypoglycaemia and hepatomegaly. Most GSD Ib patients also show neutropenia and neutrophil dysfunction and therefore are at risk of developing severe infections and inflammatory bowel disease (IBD). An increased risk for autoimmune disorders, such as thyroid autoimmunity and Crohn-like disease, has also been demonstrated, but no systematic study on the prevalence of autoimmune disorders in GSD Ib patients has ever been performed. We describe a 25-year-old patient affected by GSD Ib who developed 'seronegative' myasthenia gravis (MG), presenting with bilateral eyelid ptosis, diplopia, dysarthria, severe dysphagia, dyspnoea and fatigue. The repetitive stimulation of peripheral nerves test showed signs of exhaustion of neuromuscular transmission, particularly evident in the cranial area. Even in the absence of identifiable anti-acetylcholine receptor antibodies, seronegative MG is considered an autoimmune disorder and may be related to the disturbed immune function observed in GSD Ib patients.

Search for medium modifications of the rho meson

The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. The vector mesons, rho, omega, and varphi, are observed via their decay to e;{+}e;{-}, in order to reduce the effects of final-state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the rho meson. The rho mass spectrum is extracted from the data on various nuclei, 2H, C, Fe, and Ti. We observe no significant mass shift and some broadening consistent with expected collisional broadening for the rho meson.

Experimental study of exclusive 2H(e,e'p)n reaction mechanisms at high Q2

The reaction 2H(e,e'p)n has been studied with full kinematic coverage for photon virtuality 1.75<Q2<5.5 GeV2. Comparisons of experimental data with theory indicate that for very low values of neutron recoil momentum (p(n)<100 MeV/c) the neutron is primarily a spectator and the reaction can be described by the plane-wave impulse approximation. For 100<p(n)<750 MeV/c, proton-neutron rescattering dominates the cross section, while Delta production followed by the NDelta-->NN transition is the primary contribution at higher momenta.

The PEA15 gene is overexpressed and related to insulin resistance in healthy first-degree relatives of patients with type 2 diabetes

AIMS/HYPOTHESIS

Overexpression of the gene encoding phosphoprotein enriched in astrocytes 15 (PEA15), also known as phosphoprotein enriched in diabetes (PED), causes insulin resistance and diabetes in transgenic mice and has been observed in type 2 diabetic individuals. The aim of this study was to investigate whether PEA15 overexpression occurs in individuals at high risk of diabetes and whether it is associated with specific type 2 diabetes subphenotypes.

SUBJECTS AND METHODS

We analysed PEA15 expression in euglycaemic first-degree relatives (FDR) of type 2 diabetic subjects.

RESULTS

The expression of PEA15 in peripheral blood leucocytes (PBLs) paralleled that in fat and skeletal muscle tissues. In PBLs from the FDR, PEA15 expression was two-fold higher than in euglycaemic individuals with no family history of diabetes (control subjects), both at the protein and the mRNA level (p < 0.001). The expression of PEA15 was comparable in FDR and type 2 diabetic subjects and in each group close to one-third of the subjects expressed PEA15 levels more than 2 SD higher than the mean of control subjects. Subjects with IFG with at least one type 2 diabetes-affected FDR also overexpressed PEA15 (p < 0.05). In all the groups analysed, PEA15 expression was independent of sex and unrelated to age, BMI, waist circumference, systolic and diastolic BP, and fasting cholesterol, triacylglycerol and glucose levels. However, in euglycaemic FDR of type 2 diabetic subjects, PEA15 expression was inversely correlated with insulin sensitivity (r = -557, p = 0.01).

CONCLUSIONS/INTERPRETATION

We conclude that PEA15 overexpression represents a common defect in FDR of patients with type 2 diabetes and is correlated with reduced insulin sensitivity in these individuals.

Measurement of the N-->Delta(+)(1232) transition at high-momentum transfer by pi(0) electroproduction

We report a new measurement of the exclusive electroproduction reaction gamma(*)p-->pi(0)p to explore the evolution from soft nonperturbative physics to hard processes via the Q(2) dependence of the magnetic (M(1+)), electric (E(1+)), and scalar (S(1+)) multipoles in the N-->Delta transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c(2), 4pi center-of-mass solid angle, and Q(2) from 3 to 6 GeV(2)/c(2), the highest yet achieved. It is found that the magnetic form factor G(M)(*) decreases with Q(2) more steeply than the proton magnetic form factor, the ratio E(1+)/M(1+) is small and negative, indicating strong helicity nonconservation, and the ratio S(1+)/M(1+) is negative, while its magnitude increases with Q(2).

Search for Theta++ pentaquarks in the exclusive reaction gammap-->K+K-p

The reaction gammap --> pK+K- was studied at Jefferson Lab with photon energies from 1.8 to 3.8 GeV using a tagged photon beam. The goal was to search for a Theta++ pentaquark, a narrow, doubly charged baryon state having strangeness S=+1 and isospin I=1, in the pK+ invariant mass spectrum. No statistically significant evidence of a Theta++ was found. Upper limits on the total and differential cross section for the reaction gammap --> K-Theta++ were obtained in the mass range from 1.5 to 2.0 GeV/c2, with an upper limit for a narrow resonance with a mass M(Theta++) = 1.54 GeV/c2 of about 0.15 nb, 95% C.L.. This result places a stringent upper limit on the Theta++ width Gamma(Theta++) <0.1 MeV/c2.

A randomised controlled cross-over trial of aerobic training versus Qigong in advanced Parkinson's disease

AIM

To investigate the effects of an aerobic training in subjects with Parkinson's disease (PD) as compared to a medical Chinese exercise (Qigong).

METHODS

DESIGN

randomized controlled trial with a cross over design.

SETTING

PD out-patients referred to a Neurorehabilitation facility for the management of motor disability.

SUBJECTS

26 PD patients in Hoehn and Yahr stage II to III under stable medication were randomly allocated to either Group AT1+QG2 (receiving 20 aerobic training sessions followed by 20 ''Qigong'' group sessions with 2 month interval between the interventions), or Group QG1+AT2 (performing the same treatments with an inverted sequence).

MAIN OUTCOME MEASURES

clinical effects of treatment were sought through the Unified Parkinson's Disease Rating Scale (UPDRS), Brown's Disability Scale (B'DS), six-Minute Walking Test (6MWT), Borg scale for breathlessness, Beck Depression Inventory (BDI) and Parkinson's Disease Questionnaire-39 items (PDQ-39). A spirometry test and maximum cardiopulmonary exercise test (CPET) were also performed to determine the pulmonary function, the metabolic and cardio-respiratory requests at rest and under exercise. All measures were taken immediately before and at the completion of each treatment phase.

RESULTS

The statistical analysis focusing on the evolution of motor disability and quality of life revealed a significant interaction effect between group and time for the 6MWT (time x group effect: F: 5.4 P=0.002) and the Borg scale (time x group effect: F: 4.2 P=0.009). Post hoc analysis showed a significant increase in 6MWT and a larger decrease in Borg score after aerobic training within each subgroup, whereas no significant changes were observed during Qigong. No significant changes over time were detected through the analysis of UPDRS, B'DS, BDI and PDQ-39 scores. The analysis of cardiorespiratory parameters showed significant interaction effects between group and time for the Double Productpeak (time x group effect: F: 7.7 P=0.0003), the VO(2peak) (time x group effect: F: 4.8 P=0.007), and the VO(2)/kg ratio (time x group effect: F: 4.3 P=0.009), owing to their decrease after aerobic training to an extent that was never observed after Qigong treatment.

CONCLUSIONS

Aerobic training exerts a significant impact on the ability of moderately disabled PD patients to cope with exercise, although it does not improve their self-sufficiency and quality of life.

Measurement of deeply virtual compton scattering with a polarized-proton target

The longitudinal target-spin asymmetry AUL for the exclusive electroproduction of high-energy photons was measured for the first time in ep-->e;'pgamma. The data have been accumulated at JLab with the CLAS spectrometer using 5.7 GeV electrons and a longitudinally polarized NH3 target. A significant azimuthal angular dependence was observed, resulting from the interference of the deeply virtual Compton scattering and Bethe-Heitler processes. The amplitude of the sinvarphi moment is 0.252+/-0.042stat+/-0.020sys. Theoretical calculations are in good agreement with the magnitude and the kinematic dependence of the target-spin asymmetry, which is sensitive to the generalized parton distributions H and H.

Atorvastatin or fenofibrate on post-prandial lipaemia in type 2 diabetic patients with hyperlipidaemia

BACKGROUND

Post-prandial lipid abnormalities might contribute to the excess of cardiovascular risk typical of type 2 diabetic patients. The study evaluated the effects of atorvastatin (20 mg d(-1)) vs. fenofibrate (200 mg d(-1)) on post-prandial lipids in type 2 diabetic patients with mixed hyperlipidaemia.

MATERIALS AND METHOD

Eight type 2 diabetic patients, male/female (M/F) 6/2, age 58 +/- 5 years, body mass index (BMI) 28 +/- 3 kg m(-2) with cholesterol of low-density lipoprotein (LDL) between 100-160 mg dL(-1) and triglycerides between 150-400 mg dL(-1), participated in a randomized, cross-over study (3 months on atorvastatin and 3 months on fenofibrate). At baseline and at the end of the two treatments, the patients were given a standard fat meal; blood samples were taken before the meal and every 2 h after for the assay of cholesterol, triglycerides, apoB-48 and apoB-100 (determined by sodium dodecyl sulphate-polyacrylamide gel electrophoresis) in plasma lipoproteins and very low-density lipoprotein (VLDL) subfractions (large and small VLDL), separated by density gradient ultracentrifugation.

RESULTS

Data on fasting lipids confirmed that atorvastatin was more effective on the reduction of LDL-cholesterol, whereas fenofibrate was a better triglyceride-lowering agent. Concerning the post-prandial phase, the incremental areas under the curve (IAUC) for chylomicrons and large VLDL were reduced after both treatments, reaching statistical significance for cholesterol, triglyceride and apoB-100 content of chylomicrons only after fenofibrate administration [IAUC, (5.2 +/- 4.6 vs. 10.7 +/- 9.3) mg dL(-1) h(-1), P = 0.03; (131.3 +/- 95.1 vs. 259.1 +/- 201.5) mg dL(-1) h(-1), P = 0.02; (0.46 +/- 1 vs. 3 +/- 3.7) mg dL(-1) h(-1), P = 0.025, all respectively].

CONCLUSIONS

During the post-prandial state fenofibrate appeared to be more effective than atorvastatin in reducing the chylomicron response.

Search for the Theta+ Pentaquark in the gammad--> DeltanK+ reaction measured with the CLAS spectrometer

For the first time, the reaction gammad-->DeltanK+ has been analyzed in order to search for the exotic pentaquark baryon Theta+(1540). The data were taken at Jefferson Laboratory, using the Hall-B tagged-photon beam of energy between 0.8 and 3.6 GeV and the CEBAF Large Acceptance Spectrometer (CLAS). No statistically significant structures were observed in the nK+ invariant-mass distribution. The upper limit on the gammad-->DeltaTheta+ integrated cross section has been calculated and found to be between 5 and 25 nb, depending on the production model assumed. The upper limit on the differential cross section is also reported.

Nutrient determinants of postprandial triglyceride response in a population-based sample of type II diabetic patients

BACKGROUND

Nutrient determinants of postprandial triglyceride (TG) are matter of debate, especially for type II diabetes.

OBJECTIVE

This study was performed to evaluate the impact of dietary habits on postprandial TG response in a population-based sample of type II diabetic patients.

DESIGN

One-hundred and forty type II diabetic patients (63 men/77 women, age 45-70 years) referring to the same health district, not on hypolipidemic drugs and without any other chronic disease, performed four TG profiles (at fasting, before, 2 and 3 h after lunch) with a specific device (Accutrend GCT, Roche Diagnostics Mannheim, Germany) validated previously. Dietary habits were recorded by a dietitian utilizing a previously validated semiquantitative questionnaire.

RESULTS

Triglyceride values (mmol/l, mean +/- s.d.) were 2.22 +/- 0.93 at fasting, decreased before lunch (2.03 +/- 0.81), reached peak values 3 h after lunch (2.73 +/- 1.11). Postprandial TG increments (3 h after lunch minus pre-lunch concentration) significantly correlated with the intake (g/day) of animal protein (r = 0.20, P < 0.02), total fat (r = 0.21, P < 0.01), animal fat (r = 0.19, P < 0.03) and vegetable fat (r = 0.19, P < 0.03), also after adjusting for fasting TG and high-density lipoprotein cholesterol levels. Expressing nutrient intake as percentage of total calorie intake, total and animal fat remained significantly and directly related to postprandial TG increment (r = 0.21, P < 0.01 for total fat; r = 0.19, P < 0.03 for animal fat) whereas the percentage of carbohydrates was inversely related (r = -0.23, P < 0.007).

CONCLUSIONS

Fat intake seems the major nutritional determinant of postprandial TG response in type II diabetic patients.

Insulin resistance and impaired glucose tolerance in obese children and adolescents from Southern Italy

BACKGROUND AND AIM

Obesity in children may lead to insulin resistance and impaired glucose regulation over time. The aim of this study was to investigate the insulin resistance status and the frequency of impaired glucose regulation in obese children and adolescents from the Campania region (Southern Italy), where the prevalence of obesity is among the highest in Europe.

METHODS AND RESULTS

We studied 100 (62 male) Italian obese children and adolescents (mean age 10.1+/-2.7 years) and 50 (27 male) normal weight healthy subjects (mean age 10.2+/-2.7 years). Anthropometric measures and biochemical tests were performed in all subjects. In obese patients an oral glucose tolerance test was also performed. The estimate of insulin resistance was calculated by a homeostasis model assessment (HOMA) index. A cut-off HOMA level of >2.5 in children and >4.0 in adolescents was used to identify an insulin-resistance status. Insulin resistance was found in 40.8% of obese children and 41.2% of obese adolescents, whereas it was found in 3.0% of normal children and none of the 17 normal adolescents (p<0.0001 and p<0.002, respectively). None of the subjects had impaired fasting glucose or diabetes, while 4 obese patients had impaired glucose tolerance (4%).

CONCLUSIONS

Impaired glucose tolerance is still rare whereas insulin-resistance is already detectable in more than 40% of obese children and adolescents in Southern Italy. Our observations confirm that metabolic risk factors can be found at a very early age and strengthen the case for implementing programmes for prevention and treatment of childhood obesity.

Measurement of two- and three-nucleon short-range correlation probabilities in nuclei

The ratios of inclusive electron scattering cross sections of 4He, 12C, and 56Fe to 3He have been measured at 1 < xB <. At Q2 > 1.4 GeV2, the ratios exhibit two separate plateaus, at 1.5 < xB < 2 and at xB > 2.25. This pattern is predicted by models that include 2- and 3-nucleon short-range correlations (SRC). Relative to A = 3, the per-nucleon probabilities of 3-nucleon SRC are 2.3, 3.1, and 4.4 times larger for A = 4, 12, and 56. This is the first measurement of 3-nucleon SRC probabilities in nuclei.

Clinical phenotype and beta-cell autoimmunity in Italian patients with adult-onset diabetes

OBJECTIVE

To characterize the phenotype of a large population of Italian patients with adult onset (> or =40 years) diabetes who were attending outpatient clinics and who were screened for glutamic acid decarboxylase 65 autoantibodies (GADA), protein tyrosine phosphatase IA-2 (IA-2A) and IA-2beta/phogrin (IA-2betaA).

DESIGN AND METHODS

This was a cross-sectional study comprising a total of 881 patients, aged < or = 70 years, diagnosed with type 2 diabetes after the age of 40 years, and consecutively recruited in five clinics located in different geographic areas of Italy (Milan, Florence, Rome, Naples and Catania). Their mean disease duration was 8.1 (6.9; s.d.) years. GADA, IA-2A and IA-2betaA were measured with radiobinding assays with in vitro translated S-methionine-labelled glutamic acid decarboxylase 65 (GAD65) or IA-2 or IA-2beta. Anthropometric and clinical data were collected and compared amongst patients with or without autoantibodies.

RESULTS

Sixty-three (7.1%) patients had one or more autoantibodies, 58 (6.6%) had GADA, 22 (2.5%) had IA-2A, six (0.7%) had IA-2betaA and 19 (2.15%) had two or more autoantibodies. IA-2A or IA-2betaA, in the absence of GADA, were found in only five patients. Autoantibody-positive patients were more often female (63.5 vs 36.5%; P < 0.009), had higher glycated haemoglobin (Hb A1c) (P < 0.001), lower body mass index (BMI; P < 0.0005) and waist/hip ratio (WHR; P < 0.01); female gender being the main contributor to BMI and WHR. We did not observe any differences in age at diagnosis or duration of disease with respect to the presence or absence of islet autoantibodies. The proportion of patients on insulin therapy was higher in patients with two or more antibodies, compared with those with one antibody only, and no antibodies (P for trend < 0.001), and among patients with GADA, in those with higher antibody titre (73.9% in those with > 10 units vs 42.0% in those with < or = 10 units; P < 0.007).

CONCLUSIONS

Patients with adult onset diabetes characterized by autoimmunity to beta-cells showed a clinical phenotype with anthropometric features that differed from those classically observed in patients with type 2 diabetes. The number and titre of autoantibodies, which reflect the severity of autoimmunity and beta-cell impairment, amplified this difference. The usefulness of autoantibody screening in adult-onset diabetes is further emphasized by these findings.

Eta' photoproduction on the proton for photon energies from 1.527 to 2.227 GeV

Differential cross sections for the reaction gamma p --> eta' p have been measured with the CLAS spectrometer and a tagged photon beam with energies from 1.527 to 2.227 GeV. The results reported here possess much greater accuracy than previous measurements. Analyses of these data suggest for the first time the coupling of the eta'N channel to both the S11(1535) and P11(1710) resonances, known to couple strongly to the etaN channel in photoproduction on the proton, and the importance of J = 3/2 resonances in the process.

Search for Theta+ (1540) Pentaquark in High-Statistics Measurement of gammap-->K0K+n at CLAS

The exclusive reaction gammap-->K0K+n was studied in the photon energy range between 1.6 and 3.8 GeV searching for evidence of the exotic baryon Theta+ (1540)-->nK+. The decay to nK+requires the assignment of strangeness S=+1 to any observed resonance. Data were collected with the CLAS detector at the Thomas Jefferson National Accelerator Facility corresponding to an integrated luminosity of 70 pb-1. No evidence for the Theta+ pentaquark was found. Upper limits were set on the production cross section as function of center-of-mass angle and nK+ mass. The 95% C.L. upper limit on the total cross section for a narrow resonance at 1540 MeV was found to be 0.8 nb.

Beam-helicity asymmetries in double-charged-pion photoproduction on the proton

Beam-helicity asymmetries for the two-pion-photoproduction reaction gammap-->ppi(+)pi(-) have been studied for the first time in the resonance region for center-of-mass energies between 1.35 and 2.30 GeV. The experiment was performed at Jefferson Lab with the CEBAF Large Acceptance Spectrometer using circularly polarized tagged photons incident on an unpolarized hydrogen target. Beam-helicity-dependent angular distributions of the final-state particles were measured. The large cross-section asymmetries exhibit strong sensitivity to the kinematics and dynamics of the reaction. The data are compared with the results of various phenomenological model calculations, and show that these models currently do not provide an adequate description for the behavior of this new observable.

Protective properties of rifampin-resistant rough mutants of Brucella melitensis

Vaccination against Brucella infections in animals is usually performed by administration of live attenuated smooth B. abortus strain S19 and B. melitensis strain Rev1. They are proven effective vaccines against B. abortus in cattle and against B. melitensis and B. ovis in sheep and goats, respectively. However, both vaccines have the main drawback of inducing O-polysaccharide-specific antibodies that interfere with serologic diagnosis of disease. In addition, they retain residual virulence, being a cause of abortion in pregnant animals and infection in humans. To overcome these problems, one approach is to develop defined rough mutant Brucella strains lacking O antigen of lipopolysaccharide. B. abortus rough strain RB51, a rifampin-resistant mutant of virulent strain B. abortus 2308, is used as a vaccine against B. abortus infection in cattle in some countries. However, RB51 is not effective in sheep, and there is only preliminary evidence that it is effective in goats. In this study, we tested the efficacies of six rifampin-resistant rough strains of B. melitensis in protecting BALB/c mice exposed to B. melitensis infection. The protective properties, as well as both humoral and cellular immune responses, were assessed in comparison with those provided by B. melitensis Rev1 and B. abortus RB51 vaccines. The results indicated that these rough mutants were able to induce a very good level of protection against B. melitensis infection, similar to that provided by Rev1 and superior to that of RB51, without inducing antibodies to O antigen. In addition, all B. melitensis mutants were able to stimulate good production of gamma interferon. The characteristics of these strains encourage further evaluation of them as alternative vaccines to Rev1 in primary host species.

Onset of asymptotic scaling in deuteron photodisintegration

We investigate the transition from the nucleon-meson to the quark-gluon description of the strong interaction using the photon energy dependence of the d(gamma,p)n differential cross section for photon energies above 0.5 GeV and center-of-mass proton angles between 30 degrees and 150 degrees. A possible signature for this transition is the onset of cross-section s(-11) scaling with the total energy squared, s, at some proton transverse momentum P(T). The results show that the scaling has been reached for proton transverse momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime is reached above this momentum.

Proton source size measurements in the eA-->e'ppX reaction

Two-proton correlations at small relative momentum q were studied in the eA(3He,4He,C,Fe)-->e(')ppX reaction at E(0)=4.46 GeV using the CLAS detector at Jefferson Lab. The enhancement of the correlation function at small q was found to be in accordance with theoretical expectations. Sizes of the emission region were extracted, and proved to be dependent on A and on the proton momentum. The size of the two-proton emission region for He was measured in eA reactions for the first time.

Measurement of the exclusive 3He(e,e'p) reaction below the quasielastic peak

New, high-precision measurements of the 3He(e,e(')p) reaction using the A1 Collaboration spectrometers at the Mainz microtron MAMI are presented. These were performed in antiparallel kinematics at energy transfers below the quasielastic peak, and at a central momentum transfer of 685 MeV/c. Cross sections and distorted momentum distributions were extracted and compared to theoretical predictions and existing data. The longitudinal and transverse behavior of the cross section was also studied. Sizable differences in the cross-section behavior from theoretical predictions based on the plane wave impulse approximation were observed in both the two- and three-body breakup channels. Full Faddeev-type calculations account for some of the observed excess cross-section, but significant differences remain.

Dietary fat, insulin sensitivity and the metabolic syndrome

Insulin resistance is the pathogenetic link underlying the different metabolic abnormalities clustering in the metabolic syndrome. It can be induced by different environmental factors, including dietary habits. Consumption of energy-dense/high fat diets is strongly and positively associated with overweight that, in turn, deteriorates insulin sensitivity, particularly when the excess of body fat is located in abdominal region. Nevertheless the link between fat intake and overweight is not limited to the high-energy content of fatty foods; the ability to oxidize dietary fat is impaired in some individuals genetically predisposed to obesity. Insulin sensitivity is also affected by the quality of dietary fat, independently of its effects on body weight. Epidemiological evidence and intervention studies clearly show that in humans saturated fat significantly worsen insulin-resistance, while monounsaturated and polyunsaturated fatty acids improve it through modifications in the composition of cell membranes which reflect at least in part dietary fat composition. A recent multicenter study (KANWU) has shown that shifting from a diet rich in saturated fatty acids to one rich in monounsaturated fat improves insulin sensitivity in healthy people while a moderate alpha-3 fatty acids supplementation does not affect insulin sensitivity. There are also other features of the metabolic syndrome that are influenced by different types of fat, particularly blood pressure and plasma lipid levels. Most studies show that alpha-3 fatty acids reduce blood pressure in hypertensive but not in normotensive subjects while shifting from saturated to monounsaturated fat intake reduces diastolic blood pressure. In relation to lipid abnormalities alpha-3 fatty acids reduce plasma triglyceride levels but in parallel, increase LDL cholesterol. Substitution of unsaturated fat for saturated fat not only reduces LDL cholesterol but contributes also to reduce plasma triglycerides in insulin resistant individuals. In conclusion, there is evidence available in humans indicating that dietary fat quality influences insulin sensitivity and associated metabolic abnormalities. Therefore, prevention of the metabolic syndrome has to be targeted: (1) to correct overweight by reducing the energy density of the habitual diet (i.e., fat intake) and (2) to improve insulin sensitivity and associated metabolic abnormalities through a reduction of dietary saturated fat, partially replaced, when appropriate, by monounsaturated and polyunsaturated fats.

Diet composition and the risk of type 2 diabetes: epidemiological and clinical evidence

In the last 10 years nutritional research on diabetes has improved dramatically in terms of both number of studies produced and quality of methodologies employed. Therefore, it is now possible to attempt to provide the evidence on which nutritional recommendations for the prevention of type 2 diabetes could be based. We therefore performed a literature search and, among the papers published in indexed journals, we selected relevant epidemiological (mostly prospective) and controlled intervention studies. Lifestyle factors that have, so far, been consistently associated with increased risk of type 2 diabetes are overweight and physical inactivity. However, recent evidence from epidemiological studies has shown that the risk of type 2 diabetes is also associated with diet composition, particularly with: (1) low fibre intake; (2) a high trans fatty acid intake and a low unsaturated:saturated fat intake ratio; (3) absence of or excess alcohol consumption. All these factors are extremely common in Western populations and therefore the potential impact of any intervention on them is large: indeed, >90 % of the general population has one or more of these risk factors. The ability to correct these behaviours in the population is estimated to reduce the incidence of diabetes by as much as 87 %. Recent intervention studies have shown that type 2 diabetes can be prevented by lifestyle changes aimed at body-weight reduction, increased physical activity and multiple changes in the composition of the diet. Within this context, the average amount of weight loss needed is not large, about 5 % initial weight, which is much less than the weight loss traditionally considered to be clinically significant for prevention of type 2 diabetes. In conclusion, new emphasis on prevention by multiple lifestyle modifications, including moderate changes in the composition of the habitual diet, might limit the dramatic increase in incidence of type 2 diabetes envisaged worldwide.

Effects of short-chain fructo-oligosaccharides on glucose and lipid metabolism in mild hypercholesterolaemic individuals

BACKGROUND

The intake of 10 g/day of short-chain-fructo-oligosaccharides (sc-FOS) has been shown to increase significantly bifidus counts and to produce high amounts of short-chain fatty acids (SCFA), presumed to influence glucose and lipid metabolism.

AIM

To evaluate the effects of moderate intake of sc-FOS on glucose and lipid metabolism in individuals with mild hypercholesterolaemia.

DESIGN

A randomized double-blind sequential cross-over study.

SUBJECTS AND METHODS

Thirty subjects of both genders (20 M/10 F), mean age 45.5+/-9.9 years (M+/-SD), BMI 26.6+/-2.2 kg/m(2), with plasma cholesterol >5.17 and <7.76 mmol/l and plasma triglycerides <3.45 mmol/l, participated in the study. The study was performed after a wash-out period of 1 month and a run-in period of 1 month to stabilize patients on a standard diet (CHO 50%, fat 30%, protein 20%, fibre 20 g/day) plus placebo (maltodextrine plus aspartame 15 g/day). At the end of run-in, subjects were randomly assigned to receive sc-FOS (Actilight) (10.6g/day) or placebo (maltodextrine plus aspartame 15 g/day) with tea and/or coffee for a duration of 2 months and thereafter switched to the other treatment for additional 2 months. Plasma glucose, total and lipoprotein (VLDL, LDL, HDL) cholesterol and triglyceride concentrations were measured in the fasting state at the end of run-in and of each treatment period. At the end of the two treatment periods, patients consumed a standard test meal (protein 15%, carbohydrate 34%, fat 51%, kJ 3988) 1h after the administration of 5.3g of sc-FOS or placebo; plasma glucose, insulin, free fatty acid (FFA) and triglyceride responses to the test meal were evaluated.

RESULTS

No significant difference in fasting parameters was detected between the two treatments. After sc-FOS and placebo plasma cholesterol levels were, respectively, 6.47+/-0.70 and 6.44+/-0.78 mmol/l (n.s.) and plasma triglycerides were 1.53+/-0.71 and 1.56+/-0.53 mmol/l (n.s.). No significant differences were observed in cholesterol and triglyceride content of VLDL, LDL and HDL and in plasma Apo A1 levels; conversely, fasting plasma Lp(a) concentrations were significantly increased after sc-FOS (37+/-38 vs. 33+/-35 mg/dl; P<0.005). Postprandial responses of glucose, FFA and triglycerides were not significantly different between sc-FOS and placebo, while postprandial insulin response (incremental area) was significantly reduced after sc-FOS compared to placebo (14,490+/-7416 vs. 17,760+/-7710 pmol/l x 300 min; P<0.02).

CONCLUSIONS

A moderate intake of sc-FOS has no major effects on lipid metabolism, both in the fasting and in the postprandial period, in individuals with mild hypercholesterolaemia. A small but significant increase of Lp(a) concentrations was observed with sc-FOS consumption together with a reduction of the postprandial insulin response; however, the clinical relevance of these small effects is unclear.

Self-monitoring of plasma triglyceride levels to evaluate postprandial response to different nutrients

Self-monitoring of plasma triglycerides (TG) may be a very useful tool to monitor, on a daily basis, the TG responses to different nutrients, particularly carbohydrates (CHO) and fat, whose influence on postprandial TG levels is not very well known. Therefore, the aim of the present study was to evaluate the TG response of hypertriglyceridemic patients to a similar amount of calories deriving from different sources of CHO and fat. Thirty-nine hypertriglyceridemic patients were randomly assigned to 1 of 2 experimental groups. In 1 group (the fat group), patients were given a standard meal plus a fat supplement of 300 kcal derived from different types of fat (butter, sunflower margarine, olive oil) for dinner, once a week for 3 weeks. In the other group (the CHO group), patients consumed the same standard meal plus a supplement of 300 kcal derived from different types of CHO (bread, coke, fruit). In both groups, patients measured their plasma TG before and 3 hours after each meal by Accutrend GCT (ROCHE, Mannheim, Germany). A subgroup of patients (n = 18) also performed TG determinations 2 hours after the test meals. The 3-hour TG increments were not significantly different between the different test meals (f = 0.671; P =.52); instead, the TG increments induced by fat supplements were significantly higher than those induced by the CHO supplements (f = 14.31; P =.0001). Similar results were also obtained 2 hours after the test meals. In conclusion, this study shows that the 2- and 3-hour TG responses to fat are higher compared with that induced by carbohydrate. This point, especially if confirmed by experiments with more frequent after meal measurements and of longer duration, should be taken into account in defining the best dietary approach to lower plasma TG levels throughout the whole day.

The TB structural genomics consortium: a resource for Mycobacterium tuberculosis biology

The TB Structural Genomics Consortium is an organization devoted to encouraging, coordinating, and facilitating the determination and analysis of structures of proteins from Mycobacterium tuberculosis. The Consortium members hope to work together with other M. tuberculosis researchers to identify M. tuberculosis proteins for which structural information could provide important biological information, to analyze and interpret structures of M. tuberculosis proteins, and to work collaboratively to test ideas about M. tuberculosis protein function that are suggested by structure or related to structural information. This review describes the TB Structural Genomics Consortium and some of the proteins for which the Consortium is in the progress of determining three-dimensional structures.

Insulin sensitivity is increased and fat oxidation after a high-fat meal is reduced in normal-weight healthy men with strong familial predisposition to overweight

OBJECTIVE

To evaluate whether postprandial abnormalities of energy expenditure and/or lipid oxidation are present in healthy, normal-weight subjects with a strong family history of obesity and thus at high risk to become obese.

DESIGN

Case-control study.

SUBJECTS

A total of 16 young healthy men participated in the study. Eight subjects had both parents overweight (father's and mother's body mass index (BMI) >25 kg/m(2)) and eight had both parents with normal body weight (father's and mother's BMI<25 kg/m(2), respectively). The group of subjects with overweight parents was similar to that with normal-weight parents (control group) in terms of BMI (23.7+/-1.7 vs 22.7+/-1.1 kg/m(2)) (M+/-s.d.) and fat-free body mass (FFM) (60.5+/-4.9 vs 58.4+/-2.0 kg), but was slightly older than the control group (25.4+/-3.3 vs 22.7+/-2.4 y; P<0.05).

MEASUREMENTS

Energy expenditure (EE) was measured by indirect calorimetry, and blood samples were taken for the evaluation of metabolic variables in the fasting state and every hour for 8 h after a standard fat-rich meal (protein 15%, carbohydrate 34%, fat 51%, 4090 kJ).

RESULTS

: Fasting plasma glucose, cholesterol, HDL-cholesterol, triglyceride, free fatty acid (FFA) and leptin concentrations were similar in both groups of participants, but subjects with overweight parents has significantly lower plasma insulin concentrations (5.11+/-0.51 vs 7.07+/-1.56 microU/ml; P<0.007) and HOMA index of insulin resistance (1.1+/-0.1 vs 1.6+/-0.4; P<0.01). Postprandial plasma glucose, triglyceride, FFA and leptin concentrations were similar in the two groups, whereas insulin levels were significantly lower in the group with both parents overweight at 3, 5, 6, 7 and 8 h. Fasting and postprandial EE, and fasting lipid and carbohydrate oxidation were similar in both groups. On the contrary, postprandial carbohydrate oxidation (incremental area under curve) was significantly higher (196.25+/-94.75 vs 75.88+/-74.72 mg/kg FFM x 8 h; P<0.007) and that of lipid oxidation lower (90.93+/-80.32 vs 163.68+/-108.22 mg/kg FFM x 8 h; P<0.05) in the group of subjects with overweight parents.

CONCLUSION

Normal-weight subjects with a strong family history of obesity present a reduced lipid oxidation in the postprandial period and a metabolic profile characterized by low plasma insulin levels and the HOMA index, which is compatible with increased insulin sensitivity. These metabolic characteristics may be considered as early predictors of weight gain and are probably genetically determined.