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L Betti

Publications and source records attributed to L Betti.

27 records · Page 2Linked to original sources
PubMed1998

Walking with the advanced reciprocating gait orthosis (ARGO) in thoracic paraplegic patients: energy expenditure and cardiorespiratory performance.

The aim of this study was to quantify the energy cost and the cardiorespiratory response while walking at free speed with an Advanced Reciprocating Gait Orthosis (ARGO). The study was conducted on a group of six male paraplegic patients, age range 16-31 years (median = 22.50), with complete traumatic injuries ranging from T3 to T12 and a median time lapse from the trauma of 21 months. The data was recorded 6-8 weeks after the patients were fitted and trained to use the orthosis. Maintaining a standing position produced a significant increase of both the heart rate (HR) and the respiratory rate (RR), whilst the increase of energy consumption was not significant. The data for median speed, energy consumption and energy cost observed during free walking was similar to that of the Reciprocating Gait Orthosis (RGO) in thoracic level paraplegic individuals. This study indicates that in the utilisation of the ARGO the workload is not excessive when it is limited to maintaining a standing position. In contrast, walking results in early anaerobic conditions and unsustainable fatigue after short distances. The great energy cost recorded is considered to be a main reason for the frequent abandonment or the low utilisation of the orthosis at follow-up.

Adolescent↗
PubMed1997

Binding of the benzodiazepine ligand [3H]-Ro 15-1788 to brain membrane of the saltwater fish Mullus surmuletus.

The distribution and the pharmacological properties of the binding of the benzodiazepine receptor antagonist [3H]-Ro 15-1788 (8-fluoro-3-carboethoxy-5,6-dihydro-5-methyl-6-oxo-4H imidazol [1,5-a] 1,4 benzodiazepine) were compared in some brain membranes of the saltwater teleost fish, Mullus surmuletus: only a single population of [3H]-Ro 15-1788 binding sites was detected. The binding was saturable and reversible with a high affinity, revealing a significant population of binding sites (Kd value of 2.1 +/- 0.2 nM and Bmax value of 1400-900 fmol mg-1 of protein, depending on fish length). The highest concentration of benzodiazepine recognition sites labelled with [3H]-Ro 15-1788 was present in the optic lobe and the olfactory bulb and the lowest concentration was found in the medulla oblongata, cerebellum and spinal cord. In order to explore behavioural selectivity as a consequence of multiple receptor subtypes, six benzodiazepine receptor ligands, flunitrazepam (5-(2-fluoro-phenyl)-1,3-dihydro-1-methyl-7-nitro-2H-1, 4-benzodiazepin-2-one), alpidem, (N,N-dipropyl-6-chloro-2-(4-chlorophenyl)imidazo [1,2-a] pyridine-3- acetamide) zolpidem {N,N,6, trimethyl-2-(4-methyl-phenyl) imidazo [1,2-a] pyridine-3-acetamide hemitartrate}, methyl beta carboline-3-carboxylate (beta CCM), Ro 15-1788 and Ro 5-4864 (4'-chlorodiazepam), were tested in vitro by binding of [3H]-Ro 15-1788 to membrane preparations from various brain areas of Mullus surmuletus, Displacement studies showed a similar rank order of efficacy of various unlabelled ligands. In all regions of the brain and in the spinal cord. GABA potentiate [3H]-flunitrazepam binding in a similar order, suggesting that the BDZ recognition sites are part of the GABAA receptor structure. These results suggest that central-type benzodiazepine receptors are present in one class of benzodiazepine binding sites in the saltwater teleost fish brain of Mullus surmuletus (type I-like). Here we report initial evidence of homogeneity of subtypes of central benzodiazepine receptors in the spinal cord of the saltwater teleost fish. Mullus surmuletus.

Animals↗
PubMed1996

The serotonin transporter from human brain: purification and partial characterization.

The serotonin (5-HT) transporter from human striatum was solubilized by digitonin and purified by affinity chromatography. The native protein-detergent complex had a molecular mass of 205 kDa, as estimated by gel-exclusion chromatography of the eluates obtained from affinity chromatography. The purified 5-HT transporter migrated as a single band of 67 kDa in SDS-PAGE. To clarify the spatial relationships between the binding sites of the tricyclic antidepressants, as [3H]-imipramine, and of the selective serotonin reuptake inhibitors, as [3H]-paroxetine, on the 5'HT transporter, both radioligands were used to label it in the purification steps. [3H]-paroxetine bound with the same affinity to a single high-affinity site on both membrane and purified preparations. [3H]-imipramine labeled a high- and a low-affinity site on parent membranes, whereas it bound to a single high-affinity site on the purified extract. Tricyclic antidepressants, selective serotonin reuptake inhibitors and 5-HT itself displaced [3H]-paroxetine and [3H-]imipramine from their high-affinity binding sites on both the membrane-bound and the purified 5-HT transporter in a monophasic fashion with Hill coefficients close to unity. Furthermore, both [3H]-paroxetine and [3H]-imipramine displayed a similar maximum binding capacity on an identical protein of 205 kDa. Our results suggest overlapping binding sites for tricyclic antidepressants, selective serotonin reuptake inhibitors and 5-HT on the 5-HT transporter.

Antidepressive Agents, Tricyclic↗
PubMed1995

Improved method for polyamine determination in TMV, a rod-shaped virus.

Polyamines were measured in viruses using different techniques. An improved method of polyamine analysis is reported for tobacco mosaic virus (TMV), a rod-shaped virus (95% protein and 5% RNA), based on HPLC of sonicated PCA-treated highly purified virus suspensions. This method allowed higher and more reliable recovery of TMV polyamines (putrescine, spermidine and spermine) when compared to the HPLC of non-sonicated samples and to thin layer chromatography. It is suggested that sonication acts on PCA-precipitated protein aggregates causing the release of trapped polyamine molecules.

Chromatography, High Pressure Liquid↗
PubMed1994

Control of breathing and respiratory muscle strength in patients with multiple sclerosis.

In 11 patients with moderately severe multiple sclerosis, lasting 11.2 +/- 7.3 years, in stable condition, and in 10 age- and sex-matched control subjects, we investigated lung function, respiratory muscle strength, and ventilatory control system. Respiratory muscle strength was assessed by measuring maximal inspiratory and expiratory mouth pressures (Pimax and Pemax, respectively). Respiratory central drive was evaluated in terms of neuromuscular (P0.1) and ventilatory (Ve) output, breathing room air and during CO2 rebreathing. In the absence of any significant impairment of lung function, patients showed a reduction of Pimax and Pemax amounting to about 40 percent and 60 percent of the predicted value at functional residual capacity (FRC), respectively; a significant, inverse correlation was found between both Pimax and Pemax at FRC and the severity score of the disease. While at rest Ve was similar to that of control subjects, baseline P0.1 was significantly higher in patients (1.97 +/- 0.79 vs 0.97 +/- 0.20 cm H2O, p < 0.005). Compared with the control group, during CO2 rebreathing P0.1/PetCO2 slope, although less steep, was not dissimilar in patients (0.34 +/- 0.13 vs 0.46 +/- 0.19 cm H2O/mm Hg, NS); on the other hand, Ve/PetCO2 slope was much lower in the patient group (1.93 +/- 0.91 vs 3.27 +/- 1.11 L/min/mm Hg, p < 0.01) and was significantly related to the functional stage of disease and to Pimax and Pemax values at FRC. These results indicate that in patients with clinically stable, moderately severe multiple sclerosis, the respiratory muscle function is abnormal. Moreover, the inspiratory drive at rest is increased and the drive response to CO2 appears normal, while the ventilatory response to CO2 is significantly impaired. Respiratory muscle weakness (and/or lack of coordination) could explain, at least in part, the lower ventilatory response in these patients, whereas the mechanism of increased rate of the initial inspiratory force generation remains unclear.

Adult↗
PubMedDate not supplied

Impaired glutathione reductase activity and levels of collagenase and elastase in synovial fluid in rheumatoid arthritis.

OBJECTIVE: To test the activity of elastase, collagenase and glutathione reductase in the synovial fluid (SF) of patients with rheumatoid arthritis (RA) and in patients with osteoarthritis (OA); to correlate the elastase and collagenase activity with the glutathione reductase activity, which is important for the inactivation of oxygen free radicals. METHODS: 24 patients affected by osteoarthrosis and 24 patients affected by rheumatoid arthritis took part in the study. We measured elastase activity towards the substrate metoxysuccinyl-alanyl-alanyl-prolyl-valyl-p-nitroanilide (MeOSuc-ala-ala-proval-p-NA) which is highly specific for elastase, and insensitive to the other serine proteases, such as cathepsin G; collagenase activity was measured using [14C]-acetylated collagen as the substrate. Glutathione reductase activity was measured following the oxidation of nicotinamide adenine dinucleotide phosphate reduced (NADPH) in the presence of oxidized glutathione (GSSG). RESULTS: The concentrations of elastase, collagenase and glutathione reductase were statistically higher in patients with RA than in patients with OA. Moreover, in the SF of patients with RA we found positive correlation between enzyme activity levels. CONCLUSION: These results confirm a high activity of collagenase and elastase in the SF of patients with RA, which is about 30 times higher than that found in the SF of patients with OA. These data underline the synergic action of these enzymes in the pathogenesis of joint damage. RA patients also exhibit higher levels of glutathione reductase, which is important for the detoxification pathway of oxygen free radicals. However, compared with findings for collagenase and elastase, the increase in glutathione reductase is only three times higher than level found in the SF of OA patients. The limited increase in glutathione reductase activity during the inflammatory process might lead to an insufficient protective effect at the joint level in rheumatoid arthritis.

Adult↗