Monti Sabatini and Colli Albani: the dormant twin volcanoes at the gates of Rome.

This multi-disciplinary work provides an updated assessment of possible future eruptive scenarios for the city of Rome. Seven new 40Ar/39Ar ages from selected products of the Monti Sabatini and Vulsini volcanic districts, along with a compilation of all the literature ages on the Colli Albani and Vico products, are used to reconstruct and compare the eruptive histories of the Monti Sabatini and Colli Albani over the last 900 ka, in order to define their present state of activity. Petrographic analyses of the dated units characterize the crystal cargo, and Advanced-InSAR analysis highlights active deformation in the MS. We also review the historical and instrumental seismicity affecting this region. Based on the chronology of the most recent phases and the time elapsed between the last eruptions, we conclude that the waning/extinguishment of eruptive activity shifted progressively from NW to SE, from northern Latium toward the Neapolitan area, crossing the city of Rome. Although Monti Sabatini is unaffected by the unrest indicators presently occurring at the Colli Albani, it should be regarded as a dormant volcanic district, as the time of 70 kyr elapsed since the last eruption is of the same order of the longest dormancies occurred in the past.

Volcano-tectonic deformation in the Monti Sabatini Volcanic District at the gates of Rome (central Italy): evidence from new geochronologic constraints on the Tiber River MIS 5 terraces.

The accumulation of magma within the Monti Sabatini Volcanic District (MSVD), Italy, coupled with the extensional tectonics of the region, pose both volcanic and tectonic hazards to the city of Rome, located 20 km to the southeast. We combine 40Ar/39Ar geochronology of volcanic deposits and a geomorphologic/stratigraphic/paleomagnetic study of fluvial terraces to determine the recurrence interval and the time elapsed since the last eruption of the MSVD. Moreover, we provide a date for the youngest known eruption of the MSVD and assess the timing of the most recent volcanic phase. Results of this study show: (i) The most recent eruptive phase occurred between 100 ka and 70 ka; (ii) the anomalously high elevation of the MIS 5 terrace indicates that it was concurrent with 50 m of uplift in the volcanic area; (iii) the time since the last eruption (70 ka) exceeds the average recurrence interval (39 ky) in the last 300 ky, as well as the longest previous dormancy (50 ky) in that time span. (iv) the current duration of dormancy is similar to the timespan separating the major explosive phase that occurred 590-450 ka.

Characterizing the transition from paediatric to adult care among emerging adults with Type 1 diabetes.

AIMS: The goals of the study were to describe the transition of youth with Type 1 diabetes from paediatric to adult healthcare services, examine the link of this transition with self care and glycaemic control, and distinguish youth who received medical treatment from different physicians in terms of demographic and parent relationship variables. METHODS: Youth with Type 1 diabetes (n = 118) were enrolled in a prospective study that examined the transition from the paediatric to adult healthcare systems and were evaluated during their senior year of high school (time 1) and 1 year later (time 2). Data on self care, glycaemic control and parent relationship were collected. RESULTS: The majority of youth saw a paediatric endocrinologist at both assessments (n = 64); others saw an adult care physician at both assessments (n = 26) or transitioned from a paediatric endocrinologist to an adult care physician (n = 19). Nine youth saw no physician between time 1 and time 2. There were group differences in demographic and parent relationship variables and self-care behaviour and glycaemic control related to the transition of care. Youth who remained in the paediatric healthcare system had the best self care and did not experience declines in glycaemic control over time. CONCLUSIONS: Early transition from the paediatric healthcare system to the adult healthcare system is associated with psychosocial variables and worse glycaemic control. Future research should identify factors that determine optimal timing and strategies to avoid deterioration of care and control during this transition.

A new method of biofeedback in the management of low vision.

Twenty-eight patients with low vision were enrolled into the study. A preliminary study was carried out on 18 eyes of 13 patients with low vision who underwent visual rehabilitation with a new instrument for biofeedback (BF) applied to vision; improved biofeedback integrated system (Ibis). Successively, eight patients (16 eyes) with bilateral low vision were subjected to biofeedback in one eye. The experimental and control eye were evaluated separately. Then a placebo training was developed on seven patients (12 eyes). Visual acuity, colour vision, automated perimetry, contrast sensitivity and flash VEP were evaluated. A brief review of the literature and the possible mechanisms behind the results are discussed.

[Urethral echography: potential and limitations]. / L'ecografia uretrale: possibilità e limiti.

Since in the early years of 1980, the diagnostic for images about male's urethral injury was exclusively assigned to urethrocystography. Sially in repeated check the gonads too often are exposed to ionizing radiations. Our results show urethrocystography/ultrasonography good correlation (13/15) cases) with 86% sensibility. Even if the urethrocystography is a methodic of first instance, the urethral ultrasonography is efficacious in follow up of urethral injury, particularly in the study of anterior urethra.

High-performance liquid chromatography and photoaffinity crosslinking to explore the binding environment of nevirapine to reverse transcriptase of human immunodeficiency virus.

Nevirapine (BI-RG-587) is a potent inhibitor of the polymerase activity of reverse transcriptase of human immunodeficiency virus type-1. Nevirapine, as well as several other non-nucleoside compounds of various structural classes, bind strongly at a site which includes tyrosines 181 and 188 of the p66 subunit of reverse transcriptase. The chromatography which was utilized to explore this binding site is described. BI-RH-448 and BI-RJ-70, two tritiated photoaffinity azido analogues of nevirapine, are each crosslinked to reverse transcriptase. The use of several HPLC-based techniques employing different modes of detection makes it possible to demonstrate a dramatic difference between the two azido analogues in crosslinking behavior. In particular, by comparing HPLC tryptic peptide maps of the photoadducts formed between reverse transcriptase and each azido analogue, it can be shown that crosslinking with BI-RJ-70 but not with BI-RH-448 is more localized, stable, and hence exploitable for the identification of the specifically bonded amino acid residue(s). In addition, comparison of the tryptic maps also makes it feasible to assess which rings of the nevirapine structure are proximal or distal to amino acid side chains of reverse transcriptase. Finally, another feature of the HPLC peptide maps is the application of on-line detection by second order derivative UV absorbance spectroscopy to identify the crosslinked amino acid residue.

Comparative purification of recombinant HIV-1 and HIV-2 reverse transcriptase: preparation of heterodimeric enzyme devoid of unprocessed gene product.

A procedure for producing and purifying recombinant HIV-1 and HIV-2 reverse transcriptase (RT) is described. These enzymes are produced by Escherichia coli-transformed with a plasmid containing the gene encoding for either the human immunodeficiency virus type 1 (HIV-1) or HIV-2 RT protein. Both proteins are partially processed by host cell proteases giving rise to a mixture of heterodimeric and nonheterodimeric products, which are subsequently resolved to near homogeneity by chromatography on phosphocellulose, Q-Sepharose, and hydrophobic interaction HPLC. Both HIV-1 (66/51 kDa) and HIV-2 (68/54 kDa) heterodimeric enzymes devoid of excess unprocessed (p66 or p68) precursors are isolated, enabling comparative enzymatic characterization of the fully active (and biologically relevant) heterodimeric forms. Homogenous HIV-1 and HIV-2 RT purified by this methodology exhibit near equivalent polymerase and RNase H activities.

Measurement of amino acid compositions of glycoprotein systems by gas-phase hydrolysis and reversed-phase high-performance liquid chromatography.

Interest in glycoproteins and their compositions has increased in recent years. Work described in this report illustrates the use of an amino acid analysis protocol involving gas-phase hydrolysis and reversed-phase high-performance liquid chromatography of glycoprotein systems at microgram levels. In other amino acid analysis protocols the problem of losses of amino acids of glycoproteins has been documented. These losses were due to various reactions, referred to as browning or Maillard reactions, which yielded a residue from which amino acids were not recoverable. In our work, three glycoprotein systems are examined: ovalbumin, sICAM-1, and bovine serum albumin--which is naturally unglycosylated, but is spiked with about 30% saccharides. In all three cases, the compositional agreement between the molar ratio of amino acids determined empirically and that predicted is greater than 90%. Thus it is shown that the adverse effects of Maillard-type reactions are avoided, and the presence of carbohydrates causes negligible interferences with amino acid analysis performed under the conditions described herein.

Characterization of the binding site for nevirapine (BI-RG-587), a nonnucleoside inhibitor of human immunodeficiency virus type-1 reverse transcriptase.

Nevirapine (BI-RG-587) is a potent and specific non-nucleoside inhibitor of human immunodeficiency virus type-1 reverse transcriptase. The compound is non-competitive with respect to template, primer, and nucleoside triphosphates indicating that BI-RG-587 does not act directly at the catalytic site. The binding site for this inhibitor was investigated by employing an azido photoaffinity analogue, BI-RJ-70, to covalently label the enzyme. The resulting photoadduct was subjected to enzymatic digestion by trypsin and endoproteinase lys-C and a single, highly labeled peptide was identified as residues 174-199. Sequencing of this peptide identified Tyr-181 and Tyr-188 as labeled residues.

[ERCP in the diagnosis of bilio-pancreatic pathology. Comparison with echography and CT]. / L'ERCP nella diagnostica della patologia bilio-pancreatica. Raffronto con ecografia e TC.

The authors have evaluated both sensitivity and specificity of ERCP in comparison with other imaging methods, such as US and CT, on the basis of a study of 63 patients with suspected pancreatobiliary pathologies. Our results show ERCP of chronic pancreatitis to have 83% sensitivity and 66% specificity. As for biliary pathologies, sensitivity was 94% and specificity 88%. In pancreatic pathologies, CT sensitivity was 99% and its specificity was 70%. The combined use of ERCP and CT determines a considerable rise in the percentages, and allows the evaluation of both the excretory tree and the parenchyma. As for biliary pathologies, the role of ERCP is fundamental, since its combination with the other methods (CT: sensitivity 72%, specificity 3.5%; US: sensitivity 70%, specificity 3.5%) has not determined but a slight increase in sensitivity, and no significant increase in specificity.

Cleavage of synthetic peptides by purified poliovirus 3C proteinase.

Synthetic peptides, 14-16 residues in length, were used as substrates for purified recombinant poliovirus proteinase 3C. The sequences of the substrates correspond to the sequences of authentic cleavage sites in the poliovirus polyprotein, all of which contain Gln-Gly at the scissile bond. Specificity of cleavages was demonstrated by analysis of 3C digests of synthetic peptides. Relative rate constants for the cleavages were derived by competition experiments. The rate constants roughly correlated with the estimated half-life of the homologous precursor proteins detected in poliovirus-infected cells. The peptide most resistant to cleavage corresponded to the 3C/3D junction, a site known to be cleaved very slowly by 3C in vivo. Substitution of threonine for alanine in P4 position of this peptide, however, resulted in significant cleavage. This observation supports the hypothesis that the residue in P4 position, in addition to the Gln-Gly in P1 and P1', respectively, contributes to substrate recognition. Ac-Gln-Gly-NH2 was not a substrate for 3C.