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Biomedical subjects

G Barbato

Publications and source records attributed to G Barbato.

At least 37 records · Page 2Linked to original sources
PubMed1995

Seasonality of mood in Italy: role of latitude and sociocultural factors.

A mail survey of degree of seasonal suffering was conducted in Italy using the SPAQ (Seasonal Pattern Assessment Questionnaire). Experiencing seasonal changes as a problem was reported by more than half of the 543 responders. Both mean GSS (Global Seasonality Score) and circannual profile of 'feeling worst' yielded results similar to those reported in the USA at comparable latitudes. Global prevalences of SAD, Reverse-SAD and Sub-SAD were 4.4, 2.1 and 4.8%, respectively. Female sex and young age were associated with a higher degree of seasonal sensitivity. No clear evidence was found of higher sensitivity at higher latitudes or of a significant influence of sociocultural factors.

Adult↗
PubMed1994

Extended sleep in humans in 14 hour nights (LD 10:14): relationship between REM density and spontaneous awakening.

The sleep patterns of 8 normal subjects living in a winter-type photoperiod (10 h light and 14 h darkness; LD 10:14) for 4 weeks were characterized by the presence of periods of spontaneous wakefulness alternating with periods of spontaneous sleep. Transitions from sleep to wakefulness occurred much more frequently out of REM sleep than out of NREM sleep (P < 0.002). REM periods that terminated in wakefulness showed shorter REM durations (P < 0.0005) and higher REM densities (P < 0.0005) than REM periods that did not terminate in wakefulness. The authors discuss these results in terms of a possible relationship between REM density and arousal level. The higher REM density preceding wakefulness and the increased number of REM periods terminating in spontaneous awakenings could reflect an enhanced level of a brain arousing process, resulting from reduced sleep pressure in the extended nights.

Adult↗
PubMed1994

Production and structural characterization of amino terminally histidine tagged human oncostatin M in E. coli.

Oncostatin M is a cytokine that acts as a growth regulator on a wide variety of cells and has diverse biological activities including acute phase protein induction, LDL receptor up-regulation and cell-specific gene expression. In order to gather information about the Onc M structure, we established a protocol for large scale production and single step purification of this functional cytokine from bacterial cells. The cDNA of human Onc M was cloned by RT-PCR from total RNA of PMA induced U937 cells. After the addition of a six histidine tag at the N-terminus, the coding region of mature Onc M was cloned in the pT7.7 expression vector. Histidine tagged Onc M was overexpressed in bacterial cells and purified to homogeneity in one step on a metal chelating column. We found that recombinant 6xHis-OncM remains fully active in a growth inhibition assay. Structural characterization of the purified protein was performed by electrospray mass spectrometry, automated Edman degradation and peptide mapping by high-pressure liquid chromatography/fast-atom-bombardment mass spectrometry. Thermal and pH stability dependence of Onc M was assessed by circular dichroism spectroscopy; the helical content is about 50%, in agreement with the four helix bundle fold postulated for cytokines that bind haematopoietic receptors of type I.

Amino Acid Sequence↗
PubMed1994

Comparative hemodynamic effects of intravenous digoxin and enoximone in severe chronic heart failure.

In order to compare the acute hemodynamic effects of digoxin (0.01 mg/kg) and enoximone (1 mg/kg), a phosphodiesterase inhibitor inotropic agent, in severe chronic congestive heart failure, 8 patients (male, mean age 56.7 years, sinus rhythm) were investigated with a randomized cross-over study. Peak effect of enoximone (30 min) in comparison to that of digoxin (90 min) resulted in a similar reduction of left-ventricular filling pressure (-27 vs. -28%) and mean pulmonary artery pressure (-23 vs. -24%). Pulmonary (-39 vs. -16%; p < 0.01) and systemic vascular resistance (-27 vs. -4%; p < 0.001) were significantly lowered by enoximone. Cardiac index (+30 vs. +6%; p < 0.001) and heart rate (+11 vs. -3%; p < 0.05) were increased significantly more by enoximone than by digoxin. Since enoximone resulted in an enhancement of cardiac performance greater than that produced by digoxin, enoximone could be a useful and powerful substitute for digoxin in the acute therapy of severe chronic congestive heart failure with sinus rhythm.

Adult↗
PubMed1993

Spontaneous eye blink rate in winter seasonal affective disorder.

We investigated spontaneous eye-blink rates in 19 drug-free patients with winter seasonal affective disorder (SAD) and 18 normal control subjects. At baseline, there were no significant differences between the two groups (mean +/- SD blink rate: 15/minute +/- 8 vs. 15/minute +/- 7). Light therapy (10,000 lux: 1 hour each morning for 1 week) produced no significant change in mean (+/- SD) blink rates either in 10 SAD patients (13/minute +/- 8 vs. 10/minute +/- 7) or in 12 normal control subjects (15/minute +/- 6 vs. 14/minute +/- 6). A post hoc exploratory analysis of the effect of light therapy on premenopausal female subjects (5 patients and 9 control subjects) showed a significant decrease in mean (+/- SD) blink rate in the patients after treatment (17 +/- 6 vs. 12 +/- 8 compared with 15 +/- 7 vs. 16 +/- 5). These results do not support the idea that an elevated blink rate may be a general biological marker in SAD, but they suggest a possible link between light treatment and mechanisms that regulate blink rate in premenopausal SAD patients.

Adult↗
PubMed1993

Persistent tardive dyskinesia: demographic and pharmacological risk factors.

The demographic, clinical and pharmacological risk factors for persistent tardive dyskinesia (TD) were investigated in a sample of 1745 patients. When simultaneously adjusting for the effects of demographic and pharmacological factors using multivariate logistic regression, female sex and advanced age were positively and significantly associated with increased risk of TD. Interaction between these two variables, investigated by cross-stratification, was significant. Furthermore, high neuroleptic dose and concomitant use of neuroleptic and antiparkinsonian drugs were both significantly associated with increased risk of TD. The results support the view that both vulnerability factors and high neuroleptic doses contribute to the occurrence of TD and further stress the relevance of a conservative use of antipsychotic medication, particularly in older women.

Adolescent↗
PubMed1993

Conservation of photoperiod-responsive mechanisms in humans.

In animals, circadian pacemakers respond to seasonal changes in day length by making corresponding adjustments in the durations of diurnal and nocturnal periods of circadian rhythms; these adjustments mediate effects of photoperiod on breeding and other seasonally recurring phenomena. Little is known about photoperiod responses of human circadian pacemakers. To investigate this question, we recorded and compared circadian rhythm profiles of 15 individuals after chronic exposures to short (8 h) and long (14 h) nights. As occurs in animals, durations of nocturnal periods of active melatonin secretion (11.9 +/- 1.6 vs. 10.3 +/- 1.3 h, df = 14, t = 4.583, P < 0.0005, paired t test), high prolactin secretion (12.9 +/- 2.1 vs. 9.9 +/- 2.2 h, df = 11, t = 2.917, P < 0.01), and sleep (10.6 +/- 0.8 vs. 7.6 +/- 0.4 h, df = 14, t = 17.122, P < 0.0005) were longer after exposure to long nights than after short ones. Durations of nocturnal periods of low rectal temperature (11.6 +/- 2.3 vs. 9.5 +/- 1.6 h, df = 12, t = 3.912, P < 0.001) and rising cortisol secretion (10.8 +/- 1.6 vs. 9.3 +/- 1.9 h, df = 14, t = 3.130, P < 0.005) were also longer. Some of these differences persisted during 24-h periods of enforced wakefulness in constant dim light, indicating that prior exposure to the two regimes induced abiding changes in the timing of internal processes, such as circadian pacemaker oscillations, that control the durations of nocturnal and diurnal periods of the rhythms.

Adult↗
PubMed1992

Backbone dynamics of calmodulin studied by 15N relaxation using inverse detected two-dimensional NMR spectroscopy: the central helix is flexible.

The backbone dynamics of Ca(2+)-saturated recombinant Drosophila calmodulin has been studied by 15N longitudinal and transverse relaxation experiments, combined with 15N(1H) NOE measurements. Results indicate a high degree of mobility near the middle of the central helix of calmodulin, from residue K77 through S81, with order parameters (S2) in the 0.5-0.6 range. The anisotropy observed in the motion of the two globular calmodulin domains is much smaller than expected on the basis of hydrodynamic calculations for a rigid dumbbell type structure. This indicates that, for the purposes of 15N relaxation, the tumbling of the N-terminal (L4-K77) and C-terminal (E82-S147) lobes of calmodulin is effectively independent. A slightly shorter motional correlation time (tau c approximately 6.3 ns) is obtained for the C-terminal domain compared to the N-terminal domain (tau c approximately 7.1 ns), in agreement with the smaller size of the C-terminal domain. A high degree of mobility, with order parameters of approximately 0.5, is also observed in the loop that connects the first with the second EF-hand type calcium binding domain and in the loop connecting the third and fourth calcium binding domain.

Animals↗
PubMed1991

Secondary structure and side-chain 1H and 13C resonance assignments of calmodulin in solution by heteronuclear multidimensional NMR spectroscopy.

Heteronuclear 2D and 3D NMR experiments were carried out on recombinant Drosophila calmodulin (CaM), a protein of 148 residues and with molecular mass of 16.7 kDa, that is uniformly labeled with 15N and 13C to a level of greater than 95%. Nearly complete 1H and 13C side-chain assignments for all amino acid residues are obtained by using the 3D HCCH-COSY and HCCH-TOCSY experiments that rely on large heteronuclear one-bond scalar couplings to transfer magnetization and establish through-bond connectivities. The secondary structure of this protein in solution has been elucidated by a qualitative interpretation of nuclear Overhauser effects, hydrogen exchange data, and 3JHNH alpha coupling constants. A clear correlation between the 13C alpha chemical shift and secondary structure is found. The secondary structure in the two globular domains of Drosophila CaM in solution is essentially identical with that of the X-ray crystal structure of mammalian CaM [Babu, Y., Bugg, C. E., & Cook, W.J. (1988) J. Mol. Biol. 204, 191-204], which consists of two pairs of a "helix-loop-helix" motif in each globular domain. The existence of a short antiparallel beta-sheet between the two loops in each domain has been confirmed. The eight alpha-helix segments identified from the NMR data are located at Glu-6 to Phe-19, Thr-29 to Ser-38, Glu-45 to Glu-54, Phe-65 to Lys-77, Glu-82 to Asp-93, Ala-102 to Asn-111, Asp-118 to Glu-127, and Tyr-138 to Thr-146. Although the crystal structure has a long "central helix" from Phe-65 to Phe-92 that connects the two globular domains, NMR data indicate that residues Asp-78 to Ser-81 of this central helix adopt a nonhelical conformation with considerable flexibility.

Alanine↗
PubMed1991

1H resonance assignment and secondary structure determination of the dimerization domain of transcription factor LFB1.

We have started the structure determination of the dimerization domain of LFB1 in solution by nuclear magnetic resonance in order to elucidate the way that the LFB1 protein dimerizes and then interacts with DNA. A 32 amino acid peptide was synthesized, and full assignment of the NMR resonances in acidic solution was achieved. The secondary structure determination is presented here. Three structurally distinct regions can be distinguished. The N-terminal region from residues 1 to 6 is extended. Two helical regions span from residues 7 to 18 and from 23 to 32. The absence of dipolar effects involving residues more than four positions apart in the sequence excludes the possibilities both of a four-helix bundle formed by two hairpins and of an antiparallel dimer; the domain must therefore be arranged as a parallel dimer formed by kinked monomers. This structural solution presents important differences from the leucine zipper-type structure observed in other transcriptional activators. Although further studies are still necessary to determine the 3D structure of the peptide, we can exclude the possibility of a coiled-coil structure.

Amino Acid Sequence↗
PubMed1991

Multidimensional triple resonance NMR spectroscopy of isotopically uniformly enriched proteins: a powerful new strategy for structure determination.

A procedure is described that affords complete 1H, 13C and 15N resonance assignment in proteins of up to about 25 kDa. The new approach requires uniform isotopic enrichment of the protein with 13C and 15N and correlates resonances of adjacent nuclei using the relatively large and well-resolved one-bond J couplings. Spectral overlap, a common problem in the application of two-dimensional NMR, is removed by increasing the dimensionality of the new methods to three or four, without increasing the number of observed resonances. With complete 1H, 13C and 15N resonance assignments available, the nuclear Overhauser effect (NOE)-based interproton distance constraints can be extracted in a very straightforward manner from four-dimensional NOE spectra.

Carbon Isotopes↗
PubMed1991

Heterodetic bicyclic decapeptide cyclo (Glu1-Leu2-Pro3-Gly4-Ser5-Ile6-Pro7- Ala8) cyclo-(1 gamma-5 beta) Phe9-Gly10. Synthesis and 2-D NMR conformational analysis.

Bicyclic peptides are useful model molecules that can mimic the constrained local folding of a great number of natural peptides and proteins, such as ionophoric peptides, enzyme active site, and ligand-receptor active site. The synthesis of the bicyclic title compound with the liquid phase method is described with experimental details. Of particular interest is the heterodetic closure of the second ring. The peptide showed a complexing activity with metal cations like Ba2+, Ca2+, and Mg2+. The free bicyclic peptide conformation in solution has been studied by means of NMR spectroscopy and a plausible structure model worked out with model building on NMR constraints is proposed.

Amino Acid Sequence↗
PubMed1990

Plasma HVA, tardive dyskinesia and psychotic symptoms in long-term drug-free inpatients with schizophrenia.

Plasma homovanillic acid (pHVA) levels were measured in 16 chronically ill patients with schizophrenia who also suffered from tardive dyskinesia, and in a group of 14 chronically ill patients with schizophrenia who did not have tardive dyskinesia. All patients were studied following an extensive drug-free period (mean = 32.9 months). Patients with orofacial dyskinesia had significantly lower levels of pHVA than did controls. In patients without tardive dyskinesia, pHVA levels were significantly correlated with both positive and negative symptomatology. In contrast, pHVA levels from patients with tardive dyskinesia bore neither a significant nor a nearly significant relationship to symptomatology. The implications of these findings for dopaminergic models of tardive dyskinesia are discussed.

Aged↗
PubMed1989

A physico-chemical approach to the study of the binding interaction between S-adenosyl-L-methionine and polyanions: binding constants and nature of the interaction with sodium poly(styrene sulfonate).

The interaction between S-adenosyl-L-methionine (AdoMet) and sodium poly(styrene sulfonate) NaPSS) was studied by means of ultrafiltration and ultraviolet absorption spectroscopy at several pH values and sodium sulfate concentrations. The results obtained are interpreted mainly in terms of electrostatic interactions and permit the evaluation of the binding constants under different experimental conditions. Furthermore, ultraviolet absorption spectroscopy data show a specific short-range interaction between the aromatic electronic system of AdoMet and the NaPSS aromatic ring. The results indicate that the binding strength is greatly affected by the AdoMet positive charge on the adenine ring. The other positive charges on both the sulfonic pole and the amino acidic group of AdoMet contribute only weakly to the binding to the polyanionic matrix, thus assuring some stability of AdoMet even at physiological pH.

Anions↗
PubMed1989

[Effectiveness of retard gallopamil in patients with stress-induced ST-segment depression and silent myocardial ischemias].

At a dosage of 75 mg b.i.d., gallopamil retard represents a suitable medication for the treatment of both symptomatic and asymptomatic ischemic episodes, as could be demonstrated in patients with coronary heart disease ascertained by angiography, positive exercise testing, and more than five ischemic episodes in Holter monitoring over 48 h. The results of our study furnish proof that more than 60% of ischemic episodes recorded in patients with stable angina pectoris during Holter monitoring over 48 h, have been asymptomatic, i.e., silent. It must thus be postulated that effective antianginal therapy must be able to suppress both symptomatic and asymptomatic ischemic episodes. This should be documented by Holter monitoring over 48 h. It has not been established yet which criteria: duration of ST-segment depression, frequency of ischemic episodes, or area integral of ST-segment depression, furnish the most adequate parameters for assessment of ischemia. Assessment of the three criteria, taken together, is likely to be most reliable and should thus, in particular, be adhered to in evidencing efficacy in an antianginal drug trial.

Administration, Oral↗