Obésité et diabète. Les variations des acides gras libres circulants sous charge orale en glucose

Résumé L'étude des variations des acides gras libres (AGL) du plasma est entreprise chez 58 sujets obèses et 18 sujets normaux témoins, mis dans des conditions d'exploration identiques. On constate chez les sujets obèses un comportement global des AGL qui est différent de celui des sujets normaux témoins dans la mesure où la dépression initiale de leur taux est plus lente et le maximum de chute est différé aux temps tardifs de l'épreuve. Il en résulte une tendance globale à une absence de réascension secondaire du taux des AGL circulants, à l'inverse de ce qui succède chez le sujet normal, où la valeur moyenne des AGL à la 4^ème h de l'épreuve est plus élevée que le taux moyen de base. Tant chez le sujet normal que chez le sujet obèse, on constate d'importantes variations individuelles. Les anomalies rencontrées chez les obèses sont d'autant plus évidentes que la tolérance glucidique se rapproche des conditions du diabète; cela laisse à penser qu'il existe, chez ces sujets, des relations étroites entre la dégradation de la tolérance glucidique et les anomalies du comportement des AGL circulants. Ce dernier problème est discuté en fonction des relations entre l'obésité et la maladie diabétique.

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Summary The variations of plasma non-esterified fatty acids (NEFA) in 58 obese subjects and 18 normal controls have been studied in identical conditions of investigation. The overall behavior of NEFA in the obese differed from that in the controls in that the initial fall was slower and the maximum depression occurred late in the test. Hence the overall tendency was for the secondary rise in the NEFA level to be missing, which was the reverse of what happened in the normals, in whom the mean NEFA value at the 4th h was above the starting value. Both in normals and in obese subjects there was a considerable individual variation. The anomalies in the obese became more marked as carbohydrate tolerance approached diabetic level; this suggests that there is in these subjects a close connexion between the decline of carbohydrate tolerance and the anomalies of plasma NEFA behavior. The latter is discussed in terms of the relationships between obesity and diabetes.

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Zusammenfassung Bei 58 Fettsüchtigen und 18 Normalpersonen wurden unter identischen Versuchsbedingungen die Variationen der freien Fettsäuren des Plasma (FFA) verfolgt. Bei Fettsüchtigen wurde ein von den Normalpersonen verschiedenes Gesamtverhalten der FFA festgestellt; der Unterschied ist umso grösser je langsamer die anfängliche Senkung des FFA-Spiegels bei den Fettsüchtigen erfolgt und je mehr das Maximum der Abnahme verzögert ist. Daraus ergibt sich eine Gesamttendenz zum Fehlen des sekundären Anstiegs des zirkulierenden FFA-Spiegels, im Gegensatz zu den Verhältnissen bei Normalpersonen, wo der Mittelwert der FFA in der 4. Stunde der Probe höher ist als der mittlere Ausgangswert. Sowohl bei Normalpersonen als auch bei Fettsüchtigen werden erhebliche individuelle Unterschiede beobachtet. Die bei Fettsüchtigen beobachteten Anomalien sind umso ausgesprochener je mehr sich ihre Kohlehydrattoleranz einer diabetischen Stoffwechsellage nähert; das lässt den Verdacht aufkommen, dass bei diesen Individuen eine enge Beziehung zwischen der verminderten Glukosetoleranz und dem abnormen Verhalten der zirkulierenden FFA besteht. Dieses Problem wird im Hinblick auf die Beziehungen zwischen Fettsucht und Diabetes mellitus besprochen.

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Resumen Se emprendió el estudio de las variaciones de los ácidos grasos libres (AGL) del plasma en 58 individuos obesos y 18 testigos normales, puestos en idénticas condiciones de exploración Se constata que en los sujetos obesos un comportamiento global de los AGL es diferente al de los individuos testigos normales en la medida o la depresión de su porcentaje es más lento y el máximo de caída se difiere a los tiempos tardíos de la prueba. Resulta una tendencia global a una ausencia de reascensión secundaria del porcentaje de los AGL circulantes, al contrario de lo que sucede en el individuo normal, en el que el valor medio de los AGL a las cuatro horas de la prueba es más elevado que el porcentaje medio de base. Tanto en el sujeto normal como en el sujeto obeso, se comprueban importantes variaciones individuales. Las anomalías encontradas en los obesos son mucho más evidentes cuando la tolerancia se acerca a las condiciones de la diabetes; esto lleva a pensar que existe, en estos individuos, estrechas relaciones entre la degradación y la tolerancia glucídica y las anomalias del comportamiento de los AGL circulantes. Este último problema se discute en función de las relaciones entre la obesidad y la enfermedad diabética.

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Riassunto Le variazioni dei NEFA plasmatici sono state studiate in 58 pazienti obesi e in 18 individui normali di controllo, posti in condizioni sperimentali identiche. Nei soggetti obesi è stato osservato un comportamento globale dei NEFA diverso da quello degli individui normali di controllo, nel senso che la depressione iniziale è più lenta e la massima caduta si verifica nelle fasi tardive della prova. Ne risulta una tendenza globale all'assenza di risalita secondaria dei NEFA circolanti, contrariamente a quanto avviene nel soggetto normale, in cui il valore medio dei NEFA alla 4^a ora del test è più elevato rispetto al livello medio di base. Sia nel soggetto normale che nell'obeso, si riscontrano importanti variazioni individuali. Le anomalie rilevate negli obesi sono tanto più evidenti quanto più la tolleranza al glucosio si avvicina alle condizioni esistenti nel diabete: ciò induce a ritenere che in questi soggetti esistano stretti rapporti tra la diminuzione della tolleranza al glucosio e le anomalie del comportamento dei NEFA circolanti. Quest'ultimo problema viene discusso alla luce delle relazioni tra obesità e malattia diabetica.

     

Lack of Association Between Transforming Growth Factor Beta 1 -509C/T and +915G/C Polymorphisms and Chronic Hepatitis B in Iranian Patients

Background:

Chronic hepatitis B is one of the world''s major health concern. The etiological agent of this infection is hepatitis B virus (HBV), which can evade the immune system response. Transforming growth factor beta 1 (TGF-β1) can act against HBV by suppressing the viral replication. The TGF-β1 also plays an important role in preventing liver damage in chronically HBV infected patients.

Objectives:

In this study, the association of TGF-β1 +915G/C and -509C/T gene polymorphisms with chronic hepatitis B was evaluated in Iranian patients.

Materials and Methods:

A population-based case–control study was conducted in Taleghani Hospital, Tehran. A number of 220 patients with chronic hepatitis B and the same number of healthy control subjects were designated the case and the control groups. The PCR-Restriction Fragment Length Polymorphism Method (PCR-RFLP) method was used for genotyping both polymorphisms. Ten percent of the control samples were sequenced to confirm the results.

Results:

No statically significant differences in genotype distribution and allele frequency were observed for both polymorphisms between healthy controls and patients with chronic hepatitis B.

Conclusions:

There was no association between TGF-β1 -509C/T and +915G/C polymorphisms with chronic hepatitis B and it seems that these changes don not play a significant role in increasing the risk of chronic infection in Iranian patients.     

Individual variability in functional connectivity predicts performance of a perceptual task

People differ in their ability to perform novel perceptual tasks, both during initial exposure and in the rate of improvement with practice. It is also known that regions of the brain recruited by particular tasks change their activity during learning. Here we investigate neural signals predictive of individual variability in performance. We used resting-state functional MRI to assess functional connectivity before training on a novel visual discrimination task. Subsequent task performance was related to functional connectivity measures within portions of visual cortex and between visual cortex and prefrontal association areas. Our results indicate that individual differences in performing novel perceptual tasks can be related to individual differences in spontaneous cortical activity.     

Lateralisation in a detour test in the common wall lizard (Podarcis muralis)

Detour tests provide a reliable indicator of the presence of visual lateralisation. Previous studies on fishes and birds suggest that preferences in choosing to detour an obstacle to reach a goal are due to asymmetries of eye use. We studied detour behaviour to reach a prey in males of Podarcis muralis in order to ascertain visual laterality for a predatory task. Lizards were found to be lateralised at both individual and population levels, although only a few lizards were found to express lateralisation at the level of the individual. The preferential direction of detouring is the left route around a transparent barrier, indicating a right eye/left hemisphere use to observe the prey and confirming the results of recent work. The eye used to fixate the prey was maintained longer in the same direction the lizards subsequently chose to approach it, confirming that the preference was basically due to visual asymmetry, not to motor asymmetry. To our knowledge this is the first study of detouring conducted on sauria, demonstrating how these lizards are right eye/left hemisphere lateralised for predatory tasks at individual and population level.     

Effect of light-curing unit and adhesive system on marginal adaptation of class v composite restorations

The aim of this study was to evaluate the effect of light-curing units (LED or halogen) on the marginal adaptation of composite restorations performed with etch-and-rinse and self-etching adhesive. Class V cavities were prepared on bovine teeth with the gingival margin on dentin and the incisal margin on enamel. The cavities were restored with a micro-hybrid resin composite using an etch-and-rinse (Single Bond 2--SB) or a self-etching adhesive (Clearfil SE Bond--CL). The light-activations were performed using halogen lamp (Optilux 501--QTH) or second-generation light-emitting diode (Radii-Cal--LED) (n = 10). After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed under scanning electronic microscopy with 500x of magnification. The greatest gap width at each margin was recorded. Data were submitted to Mann-Whitney and Wilcoxon tests (a = 0.05). SB and CL showed similar behavior of enamel margins when the light-activations were performed with QTH. The same was observed for dentin margins with LED. When the LED was used, higher gap measurements at enamel margins were observed with CL, while higher gap values in dentin were observed for SB within QTH. No significant difference between substrates was found when CL was used. However, SB had significantly higher gap measurements in dentin. The light-curing unit seems to affect the marginal adaptation of resin composite restorations. However this effect was dependent on the adhesive and the location of the margin.     

Body composition and resting metabolic rate of perimenopausal women using continuous progestogen contraception

Objective The effect on body composition and in particular on fat mass (FM) of 12 months’ use of a desogestrel (DSG)-only contraceptive pill or the levonorgestrel-releasing intrauterine system (LNG-IUS) was evaluated in women in the perimenopause.

Methods An observational study comprised 102 perimenopausal women: 42 received a 75 μg DSG pill, 34 received the 52 mg LNG-IUS, and 26 received no treatment. Body composition, body weight and resting metabolic rate (RMR) were evaluated at baseline and again after 12 months.

Results FM did not change in the control group (? 0.5 ± 1.6%) but significantly increased in the LNG-IUS group (+ 1.1 ± 2.9%; p = 0.02 vs. controls) and in the DSG group (+ 2.8 ± 3.5%; p = 0.0001 vs. controls; p = 0.02 vs. LNG-IUS). Women treated with DSG or the LNG-IUS showed a non-significant increase in body weight, body mass index and waist circumference. RMR did not significantly vary in the control group (? 3.8 ± 292.9 kJ/ 24 h) and tended to decrease but not significantly in the LNG-IUS (115.5 ± 531.8 kJ/ 24 h) and DSG groups (305.9 ± 556.9 kJ/24 h).

Conclusions The results of this preliminary study seem to indicate that in perimenopausal women continuous use of the DSG-only pill and to a lesser extent the LNG-IUS may favour FM accumulation.     

Learning from other diseases: protection and pathology in chronic fungal infections

Fungal commensals coexist in a complex milieu of bacteria within the human body. An increased understanding of the importance of microbiota in shaping the host’s immune and metabolic activities has rendered fungal interactions with their hosts more complex than previously appreciated. Metagenomics has revealed the complex interactions between fungal and bacterial commensals that, either directly or through the participation of the host immune system, impact on immune homeostasis at mucosal surfaces that, in turn, lead to secondary fungal infections. Metabolomics has captured the dialogue between the mammalian host and its microbiota. It appears that the host tryptophan catabolic enzyme, indoleamine 2,3-dioxygenase 1 (IDO1) plays a dominant role in the interplay between tryptophan catabolism by microbial communities, the host’s own pathway of metabolite production, and the activation of the aryl hydrocarbon receptor (AhR)/IL-22 axis, eventually impacting on mucosal immune homeostasis and host/fungal symbiosis. Thus, the regulatory loop involving AhR and IDO1 may be exploited for the development of multi-pronged host- and microbiota-directed therapeutic approaches for mucosal and systemic fungal diseases.     

Entropy-based automated classification of independent components separated from fMCG

Fetal magnetocardiography (fMCG) is a noninvasive technique suitable for the prenatal diagnosis of the fetal heart function. Reliable fetal cardiac signals can be reconstructed from multi-channel fMCG recordings by means of independent component analysis (ICA). However, the identification of the separated components is usually accomplished by visual inspection. This paper discusses a novel automated system based on entropy estimators, namely approximate entropy (ApEn) and sample entropy (SampEn), for the classification of independent components (ICs). The system was validated on 40 fMCG datasets of normal fetuses with the gestational age ranging from 22 to 37 weeks. Both ApEn and SampEn were able to measure the stability and predictability of the physiological signals separated with ICA, and the entropy values of the three categories were significantly different at p <0.01. The system performances were compared with those of a method based on the analysis of the time and frequency content of the components. The outcomes of this study showed a superior performance of the entropy-based system, in particular for early gestation, with an overall ICs detection rate of 98.75% and 97.92% for ApEn and SampEn respectively, as against a value of 94.50% obtained with the time-frequency-based system.     

Inhibition of day-12 spleen colony-forming units by a monoclonal antibody to the murine macrophage/monocyte colony-stimulating factor receptor

Primitive hematopoietic stem cells differentiate into committed progenitors that are thought to selectively express hematopoietic growth factor receptor(s), thereby acquiring hematopoietic growth factor responsiveness. To assess whether hematopoietic stem cells express hematopoietic growth factor receptors, the progenitor activity of bone marrow (BM) fractions, isolated by expression of receptors for macrophage/monocyte colony-stimulating factor (M-CSF), were examined. Recovery of day-12 spleen colony-forming units (CFU-S) is diminished in both M-CSF receptor-positive (M-CSFR+) and M-CSFR- fractions, indicating antibody inhibition of day-12 CFU-S. Incubation of BM cells with antibody without fractionation inhibits 50% to 60% of day-12 CFU- S. This inhibition is specific (control antibodies have no effect) and reversible by removal of bound antibody at low pH. Incubating BM cells with control or antireceptor antibody does not affect day-8 CFU-S, which are predominantly erythroid. Treating sublethally irradiated mice with antibody inhibits endogenous day-12 CFU-S. These results indicate that some early progenitors express M-CSFRs, and blocking M-CSFRs inhibits the ability of these progenitors to form colonies, possibly because of inactivation caused by prolonged receptor blockade.