Influence of on-site sampling conditions on the representativeness of the sample for the analysis of trace VOCs in raw renewable gases.

In the context of the energy transition and in order to fully manage the integration of renewable and/or low-carbon gases into the gas mix, these new renewable gases need to be characterized, including volatile organic compounds (VOCs) at trace levels that may have an impact on different stages of the gas chain event at low concentrations. This study focuses on sampling because it is the first step in any method for analyzing trace VOCs and its careful execution is essential to ensure reliable results even if the on-site conditions can be variable, such as the external temperature. The stabilization time, the effect of external temperature, and the impact of using an intermediate sample cylinder prior to transfer to tubes were hence studied in the laboratory using a standard gas mixture representative of renewable gases. The latter was also studied using a real sample. To perform this study, VOCs were sampled in Tenax® TA tubes and then analyzed by thermal desorption hyphenated to comprehensive two-dimensional gas chromatography-time-of-flight mass spectrometry. The results showed that 45 min were required to stabilize the sampling system and that external temperature had little influence, limited to the heaviest compounds. Finally, the use of a cylinder to temporarily collect gas prior to transfer to tubes led to a loss of compounds, particularly when the cylinder was stored before the transfer.

Secondary solid cancer following hematopoietic cell transplantation in patients with thalassemia major.

Hematopoietic cell transplant (HCT) recipients have a substantial risk of developing secondary solid cancers (SSCs). The aim of this retrospective study was to compare the incidence of SSC in a monocentric cohort of thalassemia major (TM) patients (n=122) who received HCT versus an hematopoietic cell donor monocentric cohort (n=122) and versus a large multicenter cohort of age- and sex-matched TM patients (n=244) who received conventional therapy. With a median follow-up of 24 years, 8 transplanted patients were diagnosed with SSC at a median of 18 years after HCT and at a median age of 33 years. Three patients died of cancer progression and 5 are living after a follow-up ranging from 10 months to 16 years after SSC diagnosis. The 30-year cumulative incidence of developing SSC was 13.24%. The occurrence of solid cancers in the hematopoietic cell donor cohort was limited to only one case for a significantly lower cumulative incidence (3.23%, P=0.02) and to 3 cases in the cohort of nontransplant patients for a significantly lower cumulative incidence (1.32%, P=0.005). This study shows that the magnitude of increased risk of SST is fourfold to sixfold for patients treated with HCT as compared with hematopoietic cell donors and nontransplant patients.

Short stature and body proportion in thalassaemia.

Short stature and short trunk have been reported in thalassaemic patients. We report a study on stature and body proportions in 476 patients (2-36 years old) with beta-thalassaemia major, followed in 12 Italian centres. Auxological data (standing height, sitting height, subischial leg length, target height), haematological data (age at first transfusion, age at start of desferrioxamine [DFX] chelation, mean dose of DFX, ferritin values) and information regarding the presence of endocrine disorders and of bone lesions, were collected and analysed according to the age of the patients, in order to investigate the natural history of the disproportion and the role of siderosis, DFX toxicity and endocrine disorders. Our data indicate that about 18% of thalassaemic patients exhibit short stature; disproportion between the upper and lower body segments is present in 14%; however, a short trunk despite normal stature is present in another 40% of patients. This is due to a spinal growth impairment which starts in infancy and progressively aggravates. We think that a short trunk is peculiar to the disease itself; however, other factors such as hypogonadism, siderosis, or DFX-induced bone dysplasia are probably involved in aggravating the body disproportion in these patients.

DNA immobilization onto electrochemically functionalized Si(100) surfaces.

N-type Si(100) surfaces were modified by reduction of 4-nitrobenzenediazonium through cyclic voltammetry. Contact mode AFM was employed to produce holes in the deposited layers and cross-sectional profiles were obtained to determine their thicknesses. Layer thickness was found to increase with the number of cyclic potential scans in both aqueous and non-aqueous media. In acetonitrile, the single scan thickness was determined to be approximately 15nm, whereas for three scans the layer thickness was found to be approximately 35nm. These thicknesses were also measured and confirmed by ellipsometry. Both thicknesses are indicative of multilayer formation on the silicon surface. Layers formed in acetonitrile were more uniform and of better quality (without holes), compared to those prepared in water. This type of functionalized surface, after further cyclic voltammetric reduction of the nitro groups and treatment with glutaraldehyde, was then used to immobilize single strand DNA-C(6)H(12)NH(2) probe sequences for hybridization with complementary DNA sequences. Fluorescein-labeled probe and target oligonucleotide sequences were used to validate the immobilization of the probe layer and hybridization with the complementary sequence. No binding was observed when using a non-complementary sequence as probe.

Quantitative evaluation of oxidative stress status on peripheral blood in beta-thalassaemic patients by means of electron paramagnetic resonance spectroscopy.

High oxidative stress status (OSS) is known to be one of the most important factors determining cell injury and consequent organ damage in thalassaemic patients with secondary iron overload. Using an innovative hydroxylamine 'radical probe' capable of efficiently trapping majority of oxygen-radicals including superoxide we measured, by electron paramagnetic resonance (EPR) spectroscopy, OSS in peripheral blood of 38 thalassaemic patients compared with sex-/age-matched healthy controls. Thalassaemic patients showed sixfold higher EPR values of OSS than controls. Significantly higher EPR values of OSS were observed in those with a severe phenotype (thalassaemia major, transfusion-dependent) with respect to mild phenotype (sickle-cell/beta-thalassaemia, not transfusion-dependent) or thalassaemia intermedia. In patients with thalassaemia major, EPR values of OSS were positively correlated with serum ferritin and with alanine aminotransferase levels. In patients with sickle cell/beta-thalassaemia, there was no correlation between EPR value of OSS and all parameters considered. The type of chelating therapy (desferrioxamine or deferiprone) did not have an effect on EPR value of OSS. In conclusion, EPR 'radical probe' seems to be a valid innovative method to determine total OSS in patients affected by thalassaemia and might be used for evaluating new strategies of chelation, new chelators, or the efficacy of antioxidant formula.

[Pattern of spontaneous and post-stimulation FSH and LH in male adolescents with thalassemia]. / Pattern di FSH ed LH spontanei e dopo stimolo in adolescenti talassemici maschi.

BACKGROUND: In the last years thalassemic patients gained a good improvement in prognosis and life style. However, short stature and hypogonadism are still frequent endocrine problems in this population. METHODS: In a group of eleven thalassemic males (14-18 years old), the spontaneous nocturnal endocrine patterns of LH and FSH and plasma gonadotropins in response to GnRH were studied. The profiles were analyzed using a computer program (PULSAR) to determine the secretion pattern (number and amplitude of peaks) and the area under the curve above the secretion baseline (AUC). The endocrine status was compared with liver fibrosis, iron overload and transfusional regimen. RESULTS: A regular and homogeneous transfusion and chelation management often does not prevent pubertal failure; it is related with the degree of liver fibrosis and often it is due to hypothalamic and/or pituitary dysfunction. CONCLUSIONS: Spontaneous gonadotropin profiles can be useful to evaluate hypogonadotropic hypogonadism in order to start the correct treatment.

Spanning or looping? The order and conformation of bipolar phospholipids in lipid membranes using 2H NMR spectroscopy.

Solid-state 2H NMR spectroscopy was used to study and characterize the conformation and order of bolaform lipid membranes. A series of 2H-labeled bolaform phosphatidylcholines has been synthesized and their properties compared to a [D4]dimyristoylphosphatidylcholine (DMPC) and a [D8]-32 macrocyclic phosphatidylcholine. 31P NMR measurements establish that the aqueous dispersions of these lipids adopt lamellar phases. Computational dePakeing was used to extract the spectrum of the oriented system from spectra consisting of a superposition of randomly oriented domains in an unoriented sample. A large (> 90 %) and constant value for the normalized segmental order parameter (Smol) was observed for all positions along the diacyl chain of the bolaform lipids and only a small population (< 10%) of a less ordered conformer was observed. The less ordered conformer is assigned to the looping conformation on the basis of comparison with the deuterated macrocyclic phospholipid which has an enforced loop in its diacyl chain. The predominant population(> 90%) of the bolaform lipids is assigned to a highly ordered, spanning conformer.

Hypogonadism in beta-thalassemic adolescents: a characteristic pituitary-gonadal impairment. The ineffectiveness of long-term iron chelation therapy.

The pituitary-gonadal function was studied in 18 beta-thalassemic female adolescents, 8 with delayed puberty and 10 with primary amenorrhea,treated with repeated transfusions and long-term iron chelation therapy by subcutaneous infusion. A 100 micrograms gonadotropin-releasing hormone (GnRH) test, a double-bolus GnRH test after estradiol administration in non-responders, a 400 micrograms thyrotropin-releasing hormone (TRH) test and a 'high dose' human menopausal gonadotropin (hMG) test were performed. LH and FSH peak levels were significantly lower in thalassemic patients than in controls, both in the 100 micrograms GnRH test (LH was 4.3 +/- 0.7 mIU/ml vs 40.8 +/- 6.0 mIU/ml and FSH 3.3 +/- 0.5 mIU/ml vs 9.6 +/- 1.1 mIU/ml, respectively) and in the double-bolus GnRH test (LH was 2.3 +/- 0.2 mIU/ml vs 59.0 +/- 4.9 mIU/ml and FSH 1.8 +/- 0.3 mIU/ml vs 14.0 +/- 1.0 mIU/ml). The mean prolactin response to the TRH test was 27.8 +/- 3.2 ng/ml. After the 'high dose' hMG test 12 out of 14 admitted patients showed a poor response, lower than 250 pg/ml. Our data suggest that the hypogonadotropic condition of the thalassemic adolescents is due to pituitary hyporesponsiveness to GnRH and that most of these patients also have an impairment of ovarian function. Both conditions are a consequence of iron deposits in glands. Moreover, there is evidence that pituitary-gonadal function cannot be preserved by long-term iron chelation therapy.