Ozonation effects for excess sludge reduction on bacterial communities composition in a full-scale activated sludge plant for domestic wastewater treatment.

Activated sludge process is the most widely diffused system to treat wastewater to control the discharge of pollutants into the environment. Microorganisms are responsible for the removal of organic matter, nitrogen, phosphorous and other emerging contaminants. The environmental conditions of biological reactors significantly affects the ecology of the microbial community and, therefore, the performance of the treatment process. In the last years, ozone has been used to reduce excess sludge production by wastewater treatment plants (WWTPs), whose disposal represents one of the most relevant operational costs. The ozonation process has demonstrated to be a viable method to allow a consistent reduction in excess sludge. This study was carried out in a full-scale plant treating municipal wastewater in two parallel lines, one ozonated in the digestion tank and another used as a control. Bacterial communities of samples collected from both lines of digestion thanks were then compared to assess differences related to the ozonation treatment. Data were then analysed with terminal restriction fragment length polymorphism (T-RFLP) analysis on 16S rRNA gene. Differences between bacterial communities of both treated and untreated line appeared 2 weeks after the beginning of the treatment. Results demonstrated that ozonation treatment significantly affected the activated sludge in WWTP.

Study of the effects of transoral gastroplasty on insulin sensitivity and secretion in obese subjects.

BACKGROUND AND AIMS: Transoral gastroplasty (TOGA) recently emerged as a new, feasible and relatively safe technique for the surgical treatment of obesity. However, so far there are no data on the effects on insulin sensitivity in the literature. Our aim is to evaluate the effect of TOGA on insulin sensitivity and secretion. METHODS AND RESULTS: Nine glucose normo-tolerant obese subjects (age:41+/-6 years; BMI:42.49+/-1.03 kg/m(2)) were studied. Fat-free mass (FM) and fat mass (FM) were assessed by bioelectrical impedance; plasma glucose, insulin, and C-peptide were measured during an oral glucose tolerance test (OGTT) before and 3 months after the operation. Insulin sensitivity was calculated using the oral-glucose insulin-sensitivity index, and insulin secretion by C-peptide deconvolution. Three months after surgery, a significant (P=0.008) reduction of BMI to 35.65+/-0.65 kg/m(2), with a decrease of FM and FFM from 57.22+/-2.19 to 41.46+/-3.02 kg (P=0.008) and from 59.52+/-1.36 to 56.67+/-1.10 kg (P=0.048) respectively, was observed. Insulinemia was significantly reduced at fast and at 120 min after OGTT; in contrast, no significant change in glucose concentration was observed. Insulin sensitivity significantly increased (348.45+/-20.08 vs. 421.18+/-20.84 ml/min/m(2), P=0.038) and the incremental area of insulin secretion rate (total ISR) significantly decreased (from 235.05+/-27.50 to 124.77+/-14.50 nmol/min/m(2), P=0.021). Total ISR correlated with weight, BMI and FM (r=0.522, P=0.028; r=0.541, P=0.020; r=0.463, P=0.049, respectively). BMI represented the most powerful predictor of ISR decrease (R(2)=0.541, P=0.020). CONCLUSION: Transoral gastroplasty allows a significant weight loss 3 months after the intervention as well as an amelioration of insulin sensitivity with subsequent reduction of the insulin secretion.

Genes involved in mitochondrial biogenesis/function are induced in response to bilio-pancreatic diversion in morbidly obese individuals with normal glucose tolerance but not in type 2 diabetic patients.

AIMS/HYPOTHESIS: The mechanisms allowing normalisation of insulin sensitivity and reversal of type 2 diabetes after bilio-pancreatic diversion (BPD) have not been elucidated. We studied whether the expression of genes relevant to mitochondrial biogenesis/function is induced in response to BPD and whether the response differs between morbidly obese patients with normal glucose tolerance (NGT) and patients with type 2 diabetes. METHODS: The effect of stable weight reduction after BPD on metabolic variables and expression of nuclear genes encoding for mitochondrial proteins or regulators of mitochondrial function was investigated in skeletal muscle. Insulin sensitivity was assessed by euglycaemic-hyperinsulinaemic clamp and substrate oxidation by indirect calorimetry. RESULTS: Both NGT and type 2 diabetic patients showed a net improvement of insulin sensitivity, with the latter also showing blood glucose normalisation. NGT patients had a large increase in glucose oxidation and substantial reduction in lipid oxidation. In contrast, type 2 diabetic patients had a blunted response to BPD in terms of glucose oxidation. NGT patients showed increased expression of genes encoding mitofusin 2, porin or citrate synthase; no significant changes were detected in diabetic patients. The expression of genes regulating mitochondrial activity (PGC-1beta [also known as PPARGC1B], PGC-1alpha [also known as PPARGC1A], PPARdelta [also known as PPARD], SIRT1) was induced only in NGT patients. CONCLUSIONS/INTERPRETATION: These findings indicate that weight loss after BPD exerts a beneficial effect on insulin sensitivity via mechanisms that are independent of the expression of genes involved in mitochondrial biogenesis/activity. Furthermore, the observation that gene expression is not altered with weight loss in type 2 diabetic patients while it is induced in NGT patients suggests a heritable component.

The effect of bilio-pancreatic diversion on type 2 diabetes in patients with BMI <35 kg/m2.

AIMS/HYPOTHESIS: To aim of the study was to investigate the effect of bilio-pancreatic diversion (BPD) on type 2 diabetes in patients with BMI <35 kg/m(2). METHODS: OGTTs were performed and anthropometric data were compared between five diabetes patients (BMI 27-33 kg/m(2)) following BPD and seven diabetes patients after a low-energy diet. Insulin secretion was computed by C-peptide deconvolution. A euglycaemic-hyperinsulinaemic clamp was performed only in the BPD group and the M value measured. RESULTS: One month after BPD, fasting and 2 h post-OGTT glycaemia decreased from 15.22 +/- 3.22 to 6.22 +/- 0.51 mmol/l (p = 0.043), while insulin sensitivity increased significantly. No significant changes were observed in the low-energy diet group. Insulin secretion did not differ significantly after either intervention. Diabetes amelioration (change in HbA(1c) level) was observed up to 18 months after BPD without pharmacological therapy. CONCLUSIONS/INTERPRETATION: BPD can achieve adequate control of type 2 diabetes also in patients with BMI <35 kg/m(2). The rapid postoperative remission of diabetes is primarily related to an improvement in insulin sensitivity.

Serum haptoglobin: a novel marker of adiposity in humans.

Haptoglobin (Hp) is a glycoprotein involved in the acute phase response to inflammation. Our previous findings indicate that Hp mRNA and protein are present in the adipose tissue of rodents and that Hp gene expression is up-regulated in obese models. The aim of the present study was to establish whether Hp could be considered a marker of obesity in humans. In 312 subjects, serum Hp was correlated directly with body mass index (BMI), leptin, C-reactive protein (CRP), and age. In a multivariate stepwise regression analysis, BMI and CRP were independent determinants of serum Hp in females, with BMI having the strongest effect. CRP and age were independent determinants of serum Hp in males, although explaining only a modest percentage of the total variability. Serum Hp was positively associated with body fat, as assessed by dual-energy x-ray absorptiometry, both in female and in male groups. The level of significance improved when serum Hp was analyzed against fat mass adjusted for lean mass. Finally, Northern and Western blot analyses performed in biopsies of sc abdominal fat from 20 obese individuals showed the presence of Hp mRNA and protein in the human adipose tissue. In conclusion, serum Hp constitutes a novel marker of adiposity in humans, and the adipose tissue likely contributes to determine its levels.