Ratio Of High Molecular Weight Research Articles

Adiponectin Resistance in Obesity: Adiponectin Leptin/Insulin Interaction.

The adiponectin (APN) levels in obesity are negatively correlated with chronic subclinical inflammation markers. The hypertrophic adipocytes cause obesity-linked insulin resistance and metabolic syndrome. Furthermore, macrophage polarization is a key determinant regulating adiponectin receptor (AdipoR1/R2) expression and differential adiponectin-mediated macrophage inflammatory responses in obese individuals. In addition to decrease in adiponectin concentrations, the decline in AdipoR1/R2 messenger ribonucleic acid (mRNA) expression leads to a decrement in adiponectin binding to cell membrane, and this turns into attenuation in the adiponectin effects. This is defined as APN resistance, and it is linked with insulin resistance in high-fat diet-fed subjects. The insulin-resistant group has a significantly higher leptin-to-APN ratio. The leptin-to-APN ratio is more than twofold higher in obese individuals. An increase in expression of AdipoRs restores insulin sensitivity and β-oxidation of fatty acids via triggering intracellular signal cascades. The ratio of high molecular weight to total APN is defined as the APN sensitivity index (ASI). This index is correlated to insulin sensitivity. Homeostasis model of assessment (HOMA)-APN and HOMA-estimated insulin resistance (HOMA-IR) are the most suitable methods to estimate the metabolic risk in metabolic syndrome. While morbidly obese patients display a significantly higher plasma leptin and soluble (s)E-selectin concentrations, leptin-to-APN ratio, there is a significant negative correlation between leptin-to-APN ratio and sP-selectin in obese patients. When comparing the metabolic dysregulated obese group with the metabolically healthy obese group, postprandial triglyceride clearance, insulin resistance, and leptin resistance are significantly delayed following the oral fat tolerance test in the first group. A neuropeptide, Spexin (SPX), is positively correlated with the quantitative insulin sensitivity check index (QUICKI) and APN. APN resistance together with insulin resistance forms a vicious cycle. Despite normal or high APN levels, an impaired post-receptor signaling due to adaptor protein-containing pleckstrin homology domain, phosphotyrosine-binding domain, and leucine zipper motif 1 (APPL1)/APPL2 may alter APN efficiency and activity. However, APPL2 blocks adiponectin signaling through AdipoR1 and AdipoR2 because of the competitive inhibition of APPL1. APPL1, the intracellular binding partner of AdipoRs, is also an important mediator of adiponectin-dependent insulin sensitization. The elevated adiponectin levels with adiponectin resistance are compensatory responses in the condition of an unusual discordance between insulin resistance and APN unresponsiveness. Hypothalamic recombinant adeno-associated virus (rAAV)-leptin (Lep) gene therapy reduces serum APN levels, and it is a more efficient strategy for long-term weight maintenance.

Characteristics of indoor and personal exposure to particulate organic compounds emitted from domestic solid fuel combustion in rural areas of northwest China

Abstract Household solid fuel combustion for heating in winter is a substantial source of air pollution in rural areas of northwest China. The present study investigated the concentration characteristics and health risks of particulate matter (PM) and its organic compounds, including polycyclic aromatic hydrocarbons (PAHs), oxygenated PAHs (OPAHs), and phthalate esters (PAEs). Indoor air and housewives' personal exposure (PE) samples were collected in Guanzhong Basin, among rural households relying on various solid fuels for heating in winter. Indoor PM primarily comprised fine PM (PM2.5, 76%), and its organic compounds were identified in particular abundance in households that used coal as the only domestic fuel (Group C, 96% in PM2.5). The mean concentration of PE to PM2.5 was 307 ± 120 μg·m−3, which was 2.4-times higher than the indoor concentration (130 ± 103 μg·m−3) because of the housewives' short-term exposure to high-concentration pollution emitted by solid fuel combustion. Organic compounds exhibited the same pattern, with PE samples having a 44% higher concentration than indoor samples. The correlation of PM2.5-bound organics between indoor and PE samples in Group C (R2 = 0.9) was higher than that in the group using coal and biomass (Group M, R2 = 0.6), indicating the stronger correlation of single-fuel heating method. The PE/indoor ratio of high molecular weight (HMW) PAHs in Group C (2.5) was higher than that of the other organic compounds (1.3) because HMW PAHs emitted through coal combustion had a larger effect on PE. This further led to higher incremental lifetime cancer risks (ICLRs) via inhalation pathway among housewives in Group C (2.4- and 1.2-times higher risk for PAHs and PAEs, respectively) than among those in Group M. However, inhalational ILCR values of Group M were still 2.1–340-times higher than the international safety standard (10−6). Therefore, the upgradation of domestic fuels and heating ways is urgently needed in rural area of northwest China to reduce indoor air pollution and health risks.

Splitting nitrogen applications improves wheat storage protein composition under low N supply

AbstractFor the baking quality of wheat flours, the composition and concentration of grain protein are crucial. It is common practice to use late nitrogen (N) application to increase grain protein concentration (GPC) and hence, improve baking quality. However, the use of N fertilizer—particularly shortly before harvest—involves environmental risks. With the suitability of GPC as a parameter for baking quality predictions being more and more questioned, there are further investigations needed considering not only the GPC but also the composition of grain protein. Gluten protein composition varies depending on genotype and environmental factors, such as weather conditions and fertilization rate. To examine whether the effect of a split N application varies under different amounts of total N supply, this study investigates the effects of split nitrogen application on grain protein concentration and composition of wheat (Triticum aestivum L. cv. JB Asano) at four different N fertilization levels (0.8; 1.0; 1.2, and 1.4 g N pot−1) in a pot experiment. The GPC was affected by both, N fertilization level and split N application. In this experiment, the minimum GPC of 13%, which is required for class A wheat varieties, was only achieved when N supply was moderate (at least 1.2 g N per pot). Considering the storage protein composition, the split N application influenced the proportion of α‐/β‐gliadins and γ‐gliadins, the alterations being inconsistent. The ratio of high molecular weight (HMW) to low molecular weight (LMW) glutenin subunits was increased by the split N application only at the lowest N fertilization level. It is concluded that splitting N fertilization into three doses and hence applying one dose of N late in the season can still be a useful approach to improve GPC as well as protein composition – especially when the total N supply is low.

A Haplotype at Adiponectin Locus: Relevance with Obesity and Type 2 Diabetes

Background: Adiponectin is an anti-inflammatory insulin sensitizing adipokine. Association studies between adiponectin (ADIPOQ) gene single nucleotide polymorphisms (SNPs) and type 2 diabetes (T2D) have been reported earlier. However, results are ambiguous due to apparent contradictions. Hence, we aimed to investigate 1) the association between ADIPOQ SNPs: 11377C/G (rs266729), +10211T/G (rs17846866), +45T/G (rs2241766) and +276G/T (rs1501299), and the risk towards T2D in one precise cohort 2) genotype-phenotype association of these SNPs with various biochemical parameters like lipid profile, plasma ratio of high molecular weight (HMW) adiponectin to total adiponectin levels, and risk towards obesity and T2D. Methods: 475 diabetic patients and 493 ethnically age and sex-matched healthy controls were recruited for this study. 3mL blood was collected and plasma was separated for lipid profile and adiponectin estimation. Genomic DNA was isolated from PBMCs and was subjected to PCR-RFLP for genotyping. The ratio of plasma HMW adiponectin /total adiponectin levels was obtained from the values estimated by ELISA. Findings: Our study suggests: i) reduced HMW adiponectin /total adiponectin ratio in diabetic patients (p<0.001) and its association with +10211T/G (rs17846866), +45T/G (rs2241766) and +276G/T (rs1501299) in T2D (p<0.0001), ii) association of the above SNPs with increased Fasting Blood Glucose, Body Mass Index, Triglyceride, Total Cholesterol (p<0.0001). More interestingly, the CGGT haplotype was found to be significantly higher in obese diabetic patients (p=0.007). Interpretation: ADIPOQ +10211T/G (rs17846866), +45T/G (rs2241766) and +276G/T (rs1501299) SNPs along with decreased adiponectin and CGGT haplotype seem to lead towards altered metabolic profile. Interpretation: ADIPOQ +10211T/G (rs17846866), +45T/G (rs2241766) and +276G/T (rs1501299) SNPs along with decreased adiponectin and CGGT haplotype seem to lead towards altered metabolic profile. Funding Statement: Department of Biotechnology, New Delhi, India Declaration of Interests: No conflict of interest exists. Ethics Approval Statement: This study was carried out in agreement with the Declaration of Helsinki as approved by the Institutional Ethical Committee for Human Research (IECHR), Faculty of Science, The Maharaja Sayajirao University of Baroda, Vadodara, Gujarat, India (FS/IECHR/2016-9).

Surfactant protein-D, a potential mediator of inflammation in axial spondyloarthritis.

Surfactant protein-D (SP-D), an innate immune defence molecule of the collectin family, is expressed in lungs and additional extrapulmonary epithelia. SP-D has immune modulatory and anti-microbial effects depending on its oligomerization. The ratio of high molecular weight (HMW): low molecular weight (LMW) SP-D in serum is mainly determined by the Met11Thr polymorphism (SNP rs721917). We aimed to study the SP-D serum level and the molecular size distribution in patients with untreated axial spondyloarthritis (axSpA) as compared with control subjects. Thirty-four patients with disease modifier untreated axSpA according to the ASAS criteria, age 19-63 years, disease duration 3.9 (2.2-5.6) years were included. Demographics, smoking habits, HLA-B27 status, ASDAS, BASDAI, BASFI, BASMI and visual analogue scale scores were recorded. SP-D in serum was measured by ELISA. DNA was isolated from whole blood and single nucleotide polymorphism rs721917 was genotyped. SP-D molecular size distribution was determined using gel filtration chromatography. SP-D in serum did not differ between patients with axSpA and healthy controls, 1177 (869, 1536) vs 910 (494, 1682) (P = 0.35) and SP-D did not correlate with disease activity. However, the HMW/LMW ratio of SP-D in serum was significantly lower in axSpA, 0.38 (0.18, 0.53) compared with controls 1.49 (0.37, 3.24) when adjusting for the Met11Thr polymorphism, gender, age, BMI and smoking (P = 0.0004). There was no correlation between HMW/LMW ratio and CRP or composite diseases outcome measures. We suggest that predominance of LMW oligomeric variants of SP-D may enhance local or systemic inflammatory responses in axSpA.

Thiazolidinediones’ Insulin-Sensitizing Properties Depend on Adiponectin-Mediated Reductions in Certain Ceramide Species

Adiponectin release from adipocytes is stimulated by the thiazolidinedione (TZD) class of PPARγ agonists in a time-dependent fashion, with an increase within 10 days followed by a more robust effect within 3 weeks. Our previous work suggested that adiponectin exerts its metabolic effects in part by enhancing the deacylation of the sphingolipid ceramide, a lipotoxic metabolite stimulated by exposure to saturated fats or inflammatory mediators. Adiponectin receptors in fact display potent ceramidase activity. Ceramides and diacylglycerols correlate with impaired insulin action. The effects of 10 and 21 days’ pioglitazone (Pio; 45 mg/day) treatment on insulin sensitivity was assessed by hyperinsulinemic-euglycemic clamp studies in n=26 type 2 diabetic subjects (Diabetes. 62:1843, 2013). Total and high molecular weight (HMW) adiponectin levels in plasma were determined using a commercial sandwich ELISA kit. Sphingolipids in adipose tissue and plasma were quantified by liquid chromatography-tandem mass spectrometry. Improved hepatic and peripheral insulin sensitivity was seen after 21 days, but not 10 days, of Pio, and were highly correlated with an increased ratio of HMW adiponectin/total levels (r2=0.90). Variable responses in both total and HMW adiponectin defined subjects as Responders (R;≥1.5-fold increase with Pio) vs. Non-responders (NR; no change). Sphingosine-1P, a beneficial conversion product from ceramides, increased 2-fold and Sphinganine-1P increased 2.5-fold in R relative to NR and placebo (p=0.0286). Pio induced decreases in dihydroceramides and increases in lactosylceramides as a function of time and adiponectin levels, the functional significance of which needs to be further explored. This study suggests the insulin-sensitizing properties of TZDs critically depend on elevating circulating adiponectin levels, with an associated lowering of certain ceramide species involved in insulin resistance and inflammation. Disclosure R. Gordillo: None. K. Zhang: None. P.E. Scherer: None.

Ratio of low molecular weight serum adiponectin to the total adiponectin value is associated with type 2 diabetes through its relation to increasing insulin resistance.

AimAmong the three adiponectin isoforms, a lower ratio of high molecular weight (HMW) adiponectin to total adiponectin (TA) is well known to cause insulin resistance and type 2 diabetes (T2D). However, how the levels of other adiponectin isoforms, such as the middle molecular weight (MMW) and low molecular weight (LMW) isoforms, and their relative ratio to TA change in T2D subjects has not been determined. Therefore, we investigated the association of these adiponectin-related parameters with T2D.MethodsWe examined the associations between adiponectin-related parameters and diabetes in a group of 394 T2D subjects and 374 controls (1st group) randomly selected from among the participants in our previous study. The associations between these parameters and the HOMA-IR in a 2nd group, consisting of the subjects remaining in the 1st group after the exclusion of subjects receiving diabetic medication, were also examined.ResultIn the 1st group, after adjusting for confounding factor, the levels of all the adiponectin isoforms and the HMW/TA ratio were significantly lower among the diabetic subjects than among the controls (all P values < 0.01). On the contrary, the LMW/TA ratio was significantly higher among the diabetic subjects (P < 0.01) and was positively associated with T2D (odds ratio = 8.64, P < 0.01). In the 2nd group, the HMW/TA ratio was inversely associated with the HOMA-IR; however, the LMW/TA ratio was positively associated with the HOMA-IR (β for LMW/TA ratio = 0.89, SE = 0.24, P < 0.001), similar to the association with T2D. The MMW/TA ratio was not associated with T2D or the HOMA-IR.ConclusionThe current investigation demonstrated that, unlike the reduction in the levels of all the adiponectin isoforms and the HMW/TA ratio, an increased LMW/TA ratio was associated with T2D through its relation to insulin resistance.

Finite difference lattice Boltzmann model based on the two-fluid theory for multicomponent fluids

ABSTRACTPrevious two-fluid lattice Boltzmann (LB) models for multicomponent fluids are limited to mixtures with a low molecular weight ratio (i.e., below 9). In this paper, a finite difference-based two-fluid LB model is developed for mixtures with larger molecular weight ratios, which can be widely found in real applications. The basic idea is to use the finite difference scheme to discretize the discrete velocity LB equations derived from the two-fluid theory. The corresponding macroscopic hydrodynamic and diffusion equations are obtained by multiscale expansions. The adjusting strategy of model parameters significantly influencing the accuracy and stability of the LB model is discussed in detail. It is demonstrated that the present LB method is able to model multicomponent fluids with a high molecular weight ratio (e.g., 32). Further, the present model is applied to the simulation of multicomponent fluids in porous media.

Effect of berberine on the ratio of high-molecular weight adiponectin to total adiponectin and adiponectin receptors expressions in high-fat diet fed rats.

To assess the effects of berberine (BBR) on high-molecular weight (HMW) adiponectin and adiponectin receptors (adipoR1/adipoR2) expressions in high-fat (HF) diet fed rats. Forty Wistar male rats were randomly assigned into a normal diet fed group and three HF diet (fat for 45% calories) fed groups (n=10 for each group). All rats underwent 12 weeks of feeding. After 4 weeks feeding, rats in the two of three HF diet fed groups were treated with 150 mg·kg-1·day-1 BBR (HF+LBBR group) and 380 mg·kg-1·day-1 BBR (HF+HBBR group) by gavage once a day respectively for the next 8 weeks while the rats in other groups treated with vehicle (NF+Veh and HF+Veh). Body weight and food intake were observed and recorded on daily basis. At the end of 12 weeks, the blood, liver, epididymal fat tissues and quadriceps femoris muscles were collected. Fasting insulin, plasma fasting glucose, serum free fatty acid (FFA), total adiponectin and HMW adiponectin levels were measured by enzyme linked immunosorbent assay method. Glucose tolerance test (GTT) and insulin tolerance test (ITT) were performed to determine the insulinsensitizing. Meanwhile the homeostasis model assessment (HOMA) method was used to determine insulin resistance (HOMA-IR). The expressions of adipoR1, adipoR2 and adenosine monophophate activated protein kinase (AMPK) phosphorylation level in skeletal muscle and liver tissue were detected by Western blot. Liver and kidney toxicity were evaluated during treatment. The body weight of rats in high- or low-dose BBR group reduced as well as HOMA-IR, FFA concentrations and fasting insulin levels decreased compared with HF+Veh group (P<0.05). BBR also increased the ratio of HMW to total adiponectin in high fat-fed rats compared with rats in the HF+Veh group. High- and low-dose BBR increased adipoR1 expression in skeletal muscle by over 6- and 2-fold (P<0.05), respectively, and high-dose BBR also increased adipoR2 expression in liver tissue by over 2-fold (P<0.05). BBR significantly increased AMPK phosphorylation in HF diet rats compared with normal diet rats (P<0.05). The ratio of HMW to total adiponectin was inversely correlated with HOMA-IR (r=-0.52, P=0.001). Meantime, no liver and kidney toxicity was found in high fat-fed rats that treated by BBR. Berberine may improve insulin resistance by increasing the expression of adiponectin receptors and the ratio of HMW to total adiponectin.

Pharmacokinetics of a Recombinant Von Willebrand Factor in Patients with Severe Von Willebrand Disease

Pharmacokinetics of a Recombinant Von Willebrand Factor in Patients with Severe Von Willebrand Disease

RNA Protein Granules Modulate tau Isoform Expression and Induce Neuronal Sprouting

The neuronal microtubule-associated protein Tau is expressed in different variants, and changes in Tau isoform composition occur during development and disease. Here, we investigate a potential role of the multivalent tau mRNA-binding proteins G3BP1 and IMP1 in regulating neuronal tau expression. We demonstrate that G3BP1 and IMP1 expression induces the formation of structures, which qualify as neuronal ribonucleoprotein (RNP) granules and concentrate multivalent proteins and mRNA. We show that RNP granule formation leads to a >30-fold increase in the ratio of high molecular weight to low molecular weight tau mRNA and an ∼12-fold increase in high molecular weight to low molecular weight Tau protein. We report that RNP granule formation is associated with increased neurite formation and enhanced process growth. G3BP1 deletion constructs that do not induce granule formation are also deficient in inducing neuronal sprouting or changing the expression pattern of tau. The data indicate that granule formation driven by multivalent proteins modulates tau isoform expression and suggest a morphoregulatory function of RNP granules during health and disease.

Difference in the ratio of high-molecular weight (HMW) to total adiponectin and HMW adiponectin in late post-menopausal women.

High-molecular weight (HMW) isoform level and HMW ratio have been shown to be better predictors of insulin sensitivity and metabolic syndrome than total adiponectin level.We examined the changes in circulating levels of HMW adiponectin and ratios of HMW to total adiponectin in women during the menopausal transition. We conducted a cross-sectional study in 217 healthy women and divided them into 4 stages: 58 women in pre-menopausal, 69 women in perimenopausal, 62 women in early post-menopausal and 28 women in late post-menopausal phase. Serum levels of total adiponectin and HMW adiponectin were measured by an enzyme-linked immunosorbent assay. In late post-menopausal women, HMW adiponectin level was significantly higher than that in peri-menopausal women and the HMW to total adiponectin ratio was significantly lower than that in early post-menopausal women. In peri-menopausal women, HMW adiponectin level was significantly lower than that in pre-menopausal women and HMW to total adiponectin ratio was significantly lower than the ratios in pre-menopausal and early post-menopausal women. The ratio of HMW to total adiponectin is low in late post-menopausal women, though both levels of total and HMW adiponectin were high after menopause in our cross-sectional study.

Lower ratio of high-molecular-weight adiponectin level to total may be associated with coronary high-risk plaque

BackgroundAlthough high-molecular-weight (HMW) adiponectin is believed to protect against atherosclerosis, the association between HMW adiponectin and the composition of coronary plaques is unknown. We evaluated whether the HMW to total adiponectin ratio was associated with the presence of coronary plaque and its composition using multi-slice computed tomography coronary angiography (MSCTCA).MethodsSerum total and HMW adiponectin levels were measured in 53 consecutive patients (age, 71) with >50% coronary artery stenosis detected by MSCTCA. A low-attenuation coronary plaque was defined as a plaque with a mean CT density <50 Hounsfield units. Multivariate logistic regression analyses were performed to evaluate the predictors of the presence of low-attenuation coronary plaques, which is thought to be high risk, on CT.ResultsDecreased serum levels of total as well as HMW adiponectin were significantly associated with the presence of at least one calcified or non-calcified coronary artery plaque (total adiponectin level: odds ratio 0.76, 95% CI 0.58–0.99, P = 0.048; HMW adiponectin level: odds ratio 0.65, 95% CI 0.42–0.99, P = 0.047). A low ratio of HMW to total adiponectin was significantly associated with the presence of low-attenuation coronary plaques (4.55, 1.94–21.90, P = 0.049). However, neither the total adiponectin nor the HMW adiponectin level was associated with the presence of low-attenuation coronary plaques.ConclusionLower total or HMW adiponectin levels are associated with the presence of calcified and non-calcified coronary plaques, whereas a lower ratio of HMW to total adiponectin associated with the presence of low-attenuation coronary plaques (thought to be high risk). Measurement of total and HMW adiponectin levels and the HMW to total adiponectin ratio may be useful for risk stratification of coronary artery plaques.

Serum adipokines and adipose tissue distribution in rheumatoid arthritis and ankylosing spondylitis. A comparative study

Rheumatoid arthritis (RA) and ankylosing spondylitis (AS) are inflammatory rheumatic diseases that may modify body composition. Adipose tissue has the ability to release a wide range of products involved in physiologic functions, but also in various pathological processes, including the inflammatory/immune response. RA and AS are both associated with the development of cardiovascular complications. It is has been established that central/abdominal, and particularly intra-abdominal or visceral adiposity is closely linked to cardiovascular events. Thus, in this study, we aimed to evaluate the body composition of patients with RA or AS compared to healthy controls (HC), with a special emphasis on the visceral region. In parallel, we measured adipose products or adipokines, namely leptin, adiponectin and its high molecular weight (HMW) isoform, resistin, and ghrelin, a gastric peptide that plays a role in energetic balance. The homeostasis model assessment for insulin resistance (HOMA-IR) and atherogenic index were used to evaluate cardiovascular risk. One hundred and twelve subjects were enrolled (30 patients with RA, 31 with AS, and 51 HC). Body composition was measured using dual-energy X-ray absorptiometry to determine total fat mass and lean mass, adiposity, fat in the android and gynoid regions, and visceral fat. Patients and HC did not differ in terms of body mass index. On the contrary, adiposity was increased in RA (p = 0.01) while visceral fat was also increased, but only in women (p = 0.01). Patients with AS tended to have lower total fat mass (p = 0.07) and higher lean mass compared to HC (p = 0.07). Leptin and leptin/fat mass were decreased in male patients with AS (p < 0.01), while total adiponectin and the ratio of HMW to total adiponectin were both increased in RA (p < 0.01). There were no changes in serum resistin and ghrelin in any group of patients. HOMA-IR and the atherogenic index were not modified in RA and AS. These results confirm that body composition was altered in RA and AS, affecting distinct soft tissue compartments. The effect of the increased visceral adipose tissue on cardiovascular risk is presumably attenuated by the favorable cardiometabolic profile in women with RA, as suggested by the normal HOMA-IR and atherogenic index.

Cilnidipine regulates glucose metabolism and levels of high-molecular adiponectin in diet-induced obese mice

The aim of the present study is to examine the effects of the antihypertensive drug cilnidipine on glucose metabolism and adipocytokines, including adiponectin, in diet-induced obese (DIO) mice. The effects of cilnidipine on insulin sensitivity and the levels of adiponectin in DIO mice were examined after the mice had been treated with cilnidipine dissolved in water at a dose of 0.2 g l(-1) for 14 days. As expected, treatment with cilnidipine decreased the systolic and diastolic blood pressures in DIO mice, compared with control mice (P<0.05 for each parameter). Cilnidipine treatment improved glucose and insulin sensitivity in DIO mice. In addition, cilnidipine treatment dramatically increased the level of adiponectin in white adipose tissue (P<0.05) and the circulating levels of total and high-molecular weight (HMW) adiponectin in DIO mice (P<0.01 for each parameter). Furthermore, the secretion of HMW adiponectin and the ratio of HMW adiponectin/total adiponectin were both increased after cilnidipine treatment. Finally, the secretion of adiponectin from adipocytes was increased after cilnidipine treatment. Taken together, these results indicate that cilnidipine improves insulin tolerance and adiponectin levels, especially high-molecular type adiponectin, in DIO mice.

One Step Ultrasound Extraction and Purification Method for the Gas Chromatographic Analysis of Hydrocarbons from Marine Sediments: Application to the Monitoring of Italian Coasts

In this study, we describe the development of an ultrasound-assisted method for the simultaneous extraction and purification of hydrocarbons from marine sediments and then its application to the gas chromatographic analysis for the estimation of the biogenic anthropogenic and petrogenic sources of hydrocarbons present in marine sediments. The extraction of hydrocarbons and their simultaneous purification from other organic compounds present in sediments was performed by sonication of a three phase system consisting of sediment, hexane and a HCl medium at pH 2. This method allowed accurate recoveries of the hydrocarbon content in samples. In the following GC-FID analysis, we examined the hydrocarbon distribution in four different areas of the Italian seas determining the pristane to phytane ratio, the total odd n-alkanes to even n-alkanes ratio (carbon preference index), the low molecular weight to high molecular weight ratio, perylene content and the presence of the so called unresolved complex mixture; according to recent studies, these parameters support the identification of the biogenic, anthropogenic and petrogenic hydrocarbon sources present in environmental samples. GC chromatograms were then re-examined by means of two different statistical multivariate methods: two-dimensional mapping (2DMAP) and independent component analysis (ICA). 2DMAP showed the presence of a significant heterogeneity in the hydrocarbon composition of different areas and within samples of a same area. ICA confirmed the general heterogeneity evidenced by 2DMAP allowing in addition to characterise the hydrocarbon composition of one of the investigated areas.

Widespread release of old carbon across the Siberian Arctic echoed by its large rivers

Abstract. Over decadal-centennial timescales, only a few mechanisms in the carbon-climate system could cause a massive net redistribution of carbon from land and ocean systems to the atmosphere in response to climate warming. The largest such climate-vulnerable carbon pool is the old organic carbon (OC) stored in Arctic permafrost (perennially frozen) soils. Climate warming, both predicted and now observed to be the strongest globally in the Eurasian Arctic and Alaska, causes thaw-release of old permafrost carbon from local tundra sites. However, a central challenge for the assessment of the general vulnerability of this old OC pool is to deduce any signal integrating its release over larger scales. Here we examine radiocarbon measurements of molecular soil markers exported by the five Great Russian-Arctic Rivers (Ob, Yenisey, Lena, Indigirka and Kolyma), employed as natural integrators of carbon release processes in their watersheds. The signals held in estuarine surface sediments revealed that average radiocarbon ages of n-alkanes increased east-to-west from 6400 yr BP in Kolyma to 11 400 yr BP in Ob. This is consistent with westwards trends of both warmer climate and more degraded organic matter as indicated by the ratio of high molecular weight (HMW) n-alkanoic acids to HMW n-alkanes. The dynamics of Siberian permafrost can thus be probed via the molecular-radiocarbon signal as carried by Arctic rivers. Old permafrost carbon is at present vulnerable to mobilization over continental scales. Climate-induced changes in the radiocarbon fingerprint of released permafrost carbon will likely depend on changes in both permafrost coverage and Arctic soil hydraulics.

Distinct adiponectin profiles might contribute to differences in susceptibility to type 2 diabetes in dogs and humans

Dogs develop obesity-associated insulin resistance but not type 2 diabetes mellitus. Low adiponectin is associated with progression to type 2 diabetes in obese humans. The aims of this study were to compare total and high molecular weight (HMW) adiponectin and the ratio of HMW to total adiponectin (S(A)) between dogs and humans and to examine whether total or HMW adiponectin or both are associated with insulin resistance in naturally occurring obese dogs. We compared adiponectin profiles between 10 lean dogs and 10 lean humans and between 6 lean dogs and 6 age- and sex-matched, client-owned obese dogs. Total adiponectin was measured with assays validated in each species. We measured S(A) with velocity centrifugation on sucrose gradients. The effect of total and HMW adiponectin concentrations on MINMOD-estimated insulin sensitivity was assessed with linear regression. Lean dogs had total and HMW adiponectin concentrations three to four times higher than lean humans (total: dogs 32 ± 5.6 mg/L, humans 10 ± 1.3 mg/L, P<0.001; HMW: dogs 25 ± 4.5 mg/L, humans 6 ± 1.3 mg/L, P<0.001) and a higher S(A) (dogs: 0.78 ± 0.05; humans: 0.54 ± 0.08, P = 0.002). Adiponectin concentrations and S(A) were not lower in obese dogs (0.76 ± 0.05 in both groups; P=1). Total adiponectin, HMW adiponectin, and S(A) were not associated with insulin sensitivity in dogs. We propose that differences in adiponectin profiles between humans and dogs might contribute to the propensity of humans but not dogs to develop type 2 diabetes. Dogs with chronic, naturally occurring obesity do not have selectively reduced HMW adiponectin, and adiponectin does not appear to be important in the development of canine obesity-associated insulin resistance.

Activation of AMPK by berberine promotes adiponectin multimerization in 3T3-L1 adipocytes

Adiponectin is assembled into trimer (LMW), hexamer (MMW) and high-molecular-weight (HMW) multimer in adipocytes. The HMW adiponectin is more metabolically active and closely associated with peripheral insulin sensitivity. In this study, we reported that berberine, an isoquinoline alkaloid with insulin-sensitizing effect, inhibits the expression of adiponectin, but promotes the assembly of HMW adiponectin and increases the ratio of HMW to total adiponectin. Berberine activates AMPK. Knockdown of AMPKα1 abolishes the effect of berberine. Activation of AMPK by AICAR also increases the level of HMW adiponectin. Our study suggested that activation of AMPK by berberine promotes adiponectin multimerization.

Alterations in total and high–molecular-weight adiponectin after 3 weeks of moderate alcohol consumption in premenopausal women

Moderate alcohol consumption is associated with increased concentrations of adiponectin. Whether this is the case for both total and high-molecular-weight (HMW) adiponectin is uncertain. Furthermore, the rate at which this increase occurs is unclear. Therefore, we examined the effect of moderate alcohol consumption on total and HMW adiponectin. In a randomized, crossover trial, 24 premenopausal women who were regular alcohol consumers received beer (∼26 g alcohol) or alcohol-free beer daily for 3 weeks preceded by a 1-week washout. Blood samples were collected weekly after an overnight fast for measurement of total and HMW adiponectin and markers of glucose and lipid metabolism. There was a significant interaction (P < .05) between the 2 treatments over time for both plasma HMW and total adiponectin concentrations. Within 3 weeks, plasma total (8.2%, P = .01) and HMW (8.2%, P = .02) adiponectin levels were higher after moderate alcohol consumption compared with abstention. Changes over time in total adiponectin were positively associated with changes in HMW adiponectin during the nonalcoholic beer (r = 0.80; 95% confidence interval, 0.55-0.92) and beer (r = 0.82; 0.58-0.93) intervention. Alcohol consumption did not affect the ratio of HMW to total adiponectin or the serum glucose, insulin, hemoglobin A(1c), or triglyceride levels compared with abstention during the intervention periods. Both total and HMW adiponectin concentrations are higher after moderate alcohol consumption compared with abstention in premenopausal women. These effects were evident after at least 3 weeks of consumption and occurred concomitantly.