Odor emissions: A public health concern for health risk perception.

The olfactory nuisance, due to the emissions of active molecules, is mainly associated with unproperly managed waste disposal and animal farming. Volatile compounds e.g., aromatics, organic and inorganic sulfide compounds, as well as nitrogen and halogenated compounds are the major contributor to odor pollution generated by waste management plants; the most important source of atmospheric ammonia is produced by livestock farming. Although an odorous compound may represent a nuisance rather than a health risk, long-term exposure to a mixture of volatile compounds may represent a risk for different diseases, including asthma, atopic dermatitis, and neurologic damage. Workers and communities living close to odor-producing facilities result directly exposed to irritant air pollutants through inhalation and for this reason the cumulative health risk assessment is recommended. Health effects are related to the concentration and exposure duration to the odorants, as well as to their irritant potency and/or biotransformation in hazardous metabolites. The health effects of a single chemical are well known, while the interactions between molecules with different functional groups have still to be extensively studied. Odor emissions are often due to airborne pollutants at levels below the established toxicity thresholds. The relationship between odor and toxicity does not always occurs but depends on the specific kind of pollutant involved. Indeed, some toxic agents does not induce odor nuisance while untoxic agents do. Accordingly, the relationship between toxicity and odor nuisance should be always analyzed in detail evaluating on the characteristics of the airborne mixture and the type of the source involved.

Unifying Frequency Combs in Active and Passive Cavities: Temporal Solitons in Externally Driven Ring Lasers.

Frequency combs have become a prominent research area in optics. Of particular interest as integrated comb technology are chip-scale sources, such as semiconductor lasers and microresonators, which consist of resonators embedding a nonlinear medium either with or without population inversion. Such active and passive cavities were so far treated distinctly. Here we propose a formal unification by introducing a general equation that describes both types of cavities. The equation also captures the physics of a hybrid device-a semiconductor ring laser with an external optical drive-in which we show the existence of temporal solitons, previously identified only in microresonators, thanks to symmetry breaking and self-localization phenomena typical of spatially extended dissipative systems.

Direct thermo-optical tuning of silicon microresonators for the mid-infrared.

We use light from a visible laser diode to directly tune silicon-on-chip microresonators by thermo-optical effect. We show that this direct tuning is local, non invasive and has a much smaller time constant than global temperature tuning methods. Such an approach could prove to be highly effective for Kerr comb generation in microresonators pumped by quantum cascade lasers, which cannot be easily tuned to achieve comb generation and soliton-mode locked states.

Indoor pollution and burning practices in wood stove management.

This study evaluates effects of good burning practice and correct installation and management of wood heaters on indoor air pollution in an Italian rural area. The same study attests the role of education in mitigating wood smoke pollution. In August 2007 and winters of 2007 and 2008, in a little mountain village of Liguria Apennines (Italy), indoor and outdoor benzene, toluene, ethylbenzene, and xylene (BTEX) concentrations were measured in nine wood-heated houses. During the first sampling, several mistakes in heating plant installations and management were found in all houses. Indoor BTEX concentrations increased during use of wood burning. Low toluene/benzene ratios were in agreement with wood smoke as main indoor and outdoor pollution source. Other BTEX sources were identified as the indoor use ofsolvents andpaints and incense burning. Results obtained during 2007 were presented and discussed with homeowners. Following this preventive intervention, in the second winter sampling all indoor BTEX concentrations decreased, in spite of the colder outdoor air temperatures. Information provided to families has induced the adoption of effective good practices in stoves and fire management. These results highlight the importance ofeducation, supported by reliable data on air pollution, as an effective method to reduce wood smoke exposures.

Polycyclic aromatic hydrocarbon pollution in native and caged mussels.

During 1999, a biological monitoring study was conducted at four sites along the Ligurian coast (Cornigliano, Voltri, Vado Ligure and Sanremo). At each site the concentration and composition of polycyclic aromatic hydrocarbons (PAH) were investigated in native and caged mussels. The mussels (Mytilus galloprovincialis), sampled in the Spring and the Autumn, showed different accumulation patterns according to the source of pollution they were exposed to. The PAH concentrations were higher in the native than in the caged mussels. The coastal sites were classified according to PAH concentrations found in mussel tissue samples: Native mussels: Vado Ligure < Voltri < San-remo < = Cornigliano, Caged mussels: Vado Ligure = Voltri = San-remo << Cornigliano. The different classification is explained by the different location of the organisms: native mussels were located near the air-water interface, while caged mussels were situated at -3 m from the water surface. The PAH concentrations in the native and caged mussels showed a similar seasonal variability, and can provide the same information about the sources of PAHs.

Elevated basal insulin secretion and normal dynamic insulin sensitivity in borderline hypertension.

BACKGROUND AND AIM: Borderline hypertension is often the initial stage of stabilized hypertension. This study aimed to provide insight on insulin behavior and its relationship with glucose metabolism by investigating insulin secretion and hepatic clearance in non-steady-state conditions in borderline hypertensive patients. METHODS AND RESULTS: We studied 15 patients (6 F, 9M, 44 +/- 2 yr, 78 +/- 2 kg, systolic pressure 155 +/- 10 mmHg, diastolic 93 +/- 5) and 15 comparable healthy controls. All underwent an intravenous glucose test, with minimal model analysis to measure insulin sensitivity S1, glucose effectiveness SG, insulin pre-hepatic release, hepatic extraction, and insulin appearance rate in the systemic circulation. Basal glucose (3.98 +/- 0.12 vs 3.94 +/- 0.11 mmol/L, hypertensive vs control subjects respectively), i.v. glucose tolerance factor KG (2.0 +/- 0.2 vs 2.2 +/- 0.1% min-1), SG (0.035 +/- 0.004 vs 0.032 +/- 0.007 min-1) and S1 [3.5 +/- 0.5 vs 3.8 +/- 0.3 10(4) min-1 (microU/mL)] were similar, both basal insulin and C-peptide exhibited a marked increase (87 +/- 8 vs 46 +/- 6 pmol/L, p = 0.0003; 637 +/- 62 vs 381 +/- 76 pmol/L, p < 0.03) demonstrating insulin resistance in basal conditions. Insulin secretion per unit volume was greater in patients, both at basal (43 +/- 5 vs 24 +/- 5 pmol/L/min, p = 0.01) and after stimulation (total hormone released = 18 +/- 2 vs 11 +/- 2 nmol/L in 4 h, p = 0.022). Post-hepatic insulin delivery was also elevated (basal = 11 +/- 1 vs 6 +/- 1 pmol/L/min, p < 0.002, total = 5 +/- 1 vs 3 +/- 0.3 nmol/L in 4 h, p = 0.02), while no difference was detected in hepatic extraction (66 +/- 4% vs 66 +/- 3). CONCLUSION: Borderline hypertensive patients display normal glucose tolerance with basal insulin resistance and normal dynamic insulin sensitivity. Peripheral hyperinsulinemia derives from the combination of normal hepatic extraction with an overproduction of hormone, mostly due to the basal component. Because borderline hypertension often degenerates into overt disease, our results point to a progression that leads to the well-known insulin resistance proper to sustained hypertension.

Beta-cell response and insulin hepatic extraction in noncirrhotic alcoholic patients soon after withdrawal.

A decreased tolerance to carbohydrates has been reported in several studies of liver diseases, whereas only a few investigations have been performed in chronic noncirrhotic alcoholic patients with and without alcohol abstinence. The aim of this study was to evaluate in detail the metabolic portrait of six noncirrhotic alcoholics during the early phase of alcohol withdrawal by quantifying the main processes involved in glucose disappearance. Data from frequently sampled intravenous glucose tolerance tests (FSIGTs) were analyzed by means of the minimal model (MINMOD) approach, which provided measurements of the (prehepatic) beta-cell secretion and of insulin degradation in the liver, along with indexes of insulin sensitivity and glucose effectiveness. Plasma insulin levels were lower in the patients (basal, 3.5 +/- 0.2 v 8.0 +/- 1.8 in matching controls, P < .05; area under the curve, 1.41 +/- 0.07 mU/mL in 240 minutes v 4.06 +/- 0.37, P < .001), and C-peptide concentrations were higher (basal, 107 +/- 3.5 v 36 +/- 9 ng/dL in controls, P < .05; area under the curve, 492 +/- 118 ng/mL in 240 minutes v 245 +/- 66, P = .05). The model analysis confirmed the absence of a decrease beta-cell release; in fact, in the alcoholics there was a basal secretion of 19 +/- 5 versus 9 +/- 2 pmol/L/min in controls (P < .05) and a total release of 9.5 +/- 1.8 nmol/L in 240 minutes versus 6.5 +/- 1.4.(ABSTRACT TRUNCATED AT 250 WORDS)

Thermodynamics of condensation of nuclear chromatin. A differential scanning calorimetry study of the salt-dependent structural transitions.

We present a detailed thermodynamic investigation of the conformational transitions of chromatin in calf thymus nuclei. Differential scanning calorimetry was used as the leading method, in combination with infrared spectroscopy, electron microscopy, and techniques for the molecular characterization of chromatin components. The conformational transitions were induced by changes in the counterion concentration. In this way, it was possible to discriminate between the interactions responsible for the folding of the higher order structure and for the coiling of nucleosomal DNA. Our experiments confirm that the denaturation of nuclear chromatin at physiological ionic strength occurs at the level of discrete structural domains, the linker and the core particle, and we were able to rule out that the actual denaturation pattern might be determined by dissociation of the nucleohistone complex and successive migration of free histones toward native regions, as recently suggested. The sequence of the denaturation events is (1) the conformational change of the histone complement at 66 degrees C, (2) the unstacking of the linker DNA at 74 degrees C, and (3) the unstacking of the core particle DNA, that can be observed either at 90 or at 107 degrees C, depending on the degree of condensation of chromatin. Nuclear chromatin unfolds in low-salt buffers, and can be refolded by increasing the ionic strength, in accordance with the well-known behavior of short fragments. The process is athermal, therefore showing that the stability of the higher order structure depends on electrostatic interactions. The transition between the folded conformation and the unfolded one proceeds through an intermediate condensation state, revealed by an endotherm at 101 degrees C. The analysis of the thermodynamic parameters of denaturation of the polynucleosomal chain demonstrates that the wrapping of the DNA around the histone octamer involves a large energy change. The most striking observation concerns the linker segment, which melts a few degrees below the peak temperature of naked DNA. This finding is in line with previous thermal denaturation investigations on isolated chromatin at low ionic strength, and suggests that a progressive destabilization of the linker occurs in the course of the salt-induced coiling of DNA in the nucleosome.

Insulin resistance in myotonic dystrophy.

The aim of the present study was to obtain a comprehensive picture of the rate of insulin secretion and of tissue sensitivity to the endogenous hormone in myotonic dystrophy patients (MyD). The minimal model approach was utilized for the analysis of frequently sampled intravenous glucose tolerance test data (FSIGT). This method provided the characteristic parameters: SI, insulin sensitivity index; SG fractional glucose disappearance independent of dynamic insulin; n, fractional insulin clearance; phi 1 and phi 2 first and second phase insulin delivery sensitivities to glucose stimulation. In MyD patients SI was reduced (p less than 0.01) by 71% to 1.4 +/- 0.3 x 10(-4) min-1/(microU/ml), whereas in controls it was 4.85 +/- 0.77; SG was within the normal range: 0.044 +/- 0.012 min-1 in MyD patients and 0.036 +/- 0.017 min-1 in controls; phi 1 increased in MyD patients (7.4 +/- 1.3 min (microU/ml)/(mg/dl) versus 4.1 +/- 1.2 in controls); phi 2 increased in MyD patients (126 +/- 47 x 10(4) min-2/(microU/ml)/(mg/dl) versus 17 +/- 6 in controls; p less than 0.05). MyD patients showed a normal tolerance with the glucose disappearance constant, KG within the normal range: 2.75 versus 2.62% min-1 in controls. In MyD patients insulin resistance was associated with a higher than normal insulin delivery for both secretory phases, although the second phase was responsible for releasing a greater amount of hormone. In conclusion MyD patients try to compensate for overall insulin resistance by a more marked pancreatic response.

Lack of DNA alterations induced by orotic acid in rat liver as evaluated with two DNA unwinding methods.

One percent orotic acid supplemented diet is a promoting treatment in the rat model of liver carcinogenesis. After treatment with this type of diet, DNA alterations were observed using alkaline sucrose gradients and alkaline elution methods. In this work we have utilized two unwinding methods for the detection of DNA fragmentation. One method is a viscosimetric method in which the rate of increase in DNA viscosity with time is related to the rate of alkaline DNA unwinding. The second method measures fluorimetrically the amount of renatured and denatured DNA after different times allowed for alkaline DNA unwinding. These two methods are very sensitive in detecting DNA breaks induced by typical alkylating agents, X-rays and H2O2. The two unwinding methods were clearly negative for the orotic acid supplemented diet. We suggest that the DNA alterations detected with alkaline sucrose gradients and alkaline elution methods, after promoting treatment with orotic acid, are probably different from the DNA breaks induced by typical alkylating agents, X-rays and H2O2.

Continuous ambulatory peritoneal dialysis (CAPD) of children with amino acid solutions: technical and metabolic aspects.

The changes in plasma and dialysate amino acids (AA) in 7 continuous ambulatory peritoneal dialysis (CAPD) children after dialysis with a 1% AA solution were compared with a glucose-containing solution. During the AA-exchange, the plasma levels of individual AA reached their peaks after 1 h, with their percentage increments significantly correlated (p less than 0.001) with the ratio of the amount of AA in the bag to the basal plasma concentration. The plasma concentration of methionine, valine, phenylalanine, and isoleucine remained higher than the basal value at 4 h. The amount of AA absorbed was 66% after 1 h, and 86% after 4 h and 6 h, corresponding to 2574 +/- 253 mumol/kg body wt. During glucose-dialysis (1.36%), levels of histidine, methionine, valine, phenylalanine, and isoleucine were significantly decreased in plasma after 1 h, and stayed low throughout the dialysis period. The loss of AA with the peritoneal effluent was 116 +/- 69 mumol/kg/body wt. From this study, it seems that using an AA dialysis solution, with 1 exchange per day, might limit the daily glucose load and compensate for AA losses by supplying an extra amount of AA and by reducing the loss of other AA not contained in dialysis solutions. The AA pattern in plasma following AA-dialysis resembles that observed after a protein meal, with no signs of persistently high, nonphysiological levels.

Peroxidative damage of the erythrocyte membrane in children with nephrotic syndrome.

The structural composition of erythrocyte ghosts was analysed in children affected by steroid-responsive (SRNS) and unresponsive nephrotic syndrome (SUNS). No variation of either intrinsic or extrinsic ghost proteins was found by discontinuous SDS-electrophoresis associated with a very sensitive double staining technique. By contrast, the composition of inner-layer phospholipids--phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS)--was altered in SRNS with minor changes also involving phosphatidic acid, phosphatidyl inositol and lysophosphatidyl choline. Signs of peroxidative damage were present in both SRNS and SUNS ghosts and inside the cells; these included high levels of fluorescent amino-iminopropene derivates of PE and PS, increased intraerythrocytic amounts of malonyldialdehyde and decreased levels of reduced glutathione. Taken together these results support the concept that in SRNS and SUNS erythrocytes are target cells for peroxidative damage. In SRNS peroxidation of membrane lipids results in a marked alteration of the phospholipid composition of erythrocyte ghosts.