Recurrence quantification analysis of heart rate variability during continuous incremental exercise test in obese subjects.

The present paper concerns a new description of changing in metabolism during incremental exercises test that permit an individually tailored program of exercises for obese subjects. We analyzed heart rate variability from RR interval time series (tachogram) with an alternative approach, the recurrence quantification analysis, that allows a description of a time series in terms of its dynamic structure and is able to identify the phase transitions. A transition in cardiac signal dynamics was detected and it perfectly reflects the aerobic threshold, as identified by gas exchange during an incremental exercise test, revealing the coupling from the respiratory system toward the heart. Moreover, our analysis shows that, in the recurrence plot of RR interval, it is possible to identify a specific pattern that allows to identify phase transitions between different dynamic regimes. The perfect match of the occurrence of the phase transitions with changes observed in the VO2 consumption, the gold standard approach to estimate thresholds, strongly supports the possibility of using our analysis of RR interval to detect metabolic threshold. In conclusion, we propose a novel nonlinear data analysis method that allows for an easy and personalized detection of thresholds both from professional and even from low-cost wearable devices, without the need of expensive gas analyzers.

Real-life impact of early interferon beta therapy in relapsing multiple sclerosis.

OBJECTIVE: Recent findings support greater efficacy of early vs. delayed interferon beta (IFNbeta) treatment in patients with a first clinical event suggestive of multiple sclerosis (MS). We aimed to evaluate the effectiveness of early IFNbeta treatment in definite relapsing-remitting MS (RRMS) and to assess the optimal time to initiate IFNbeta treatment with regard to the greatest benefits on disability progression. METHODS: A cohort of 2,570 IFNbeta-treated RRMS patients was prospectively followed for up to 7 years in 15 Italian MS Centers. A Cox proportional hazards regression model adjusted for propensity score (PS) quintiles was used to assess differences between groups of patients with early vs. delayed IFNbeta treatment on risk of reaching a 1-point progression in the Expanded Disability Status Scale (EDSS) score, and the EDSS 4.0 and 6.0 milestones. A set of PS-adjusted Cox hazards regression models were calculated according to different times of treatment initiation (within 1 year up to within 5 years from disease onset). A sensitivity analysis was performed to assess the robustness of findings. RESULTS: The lowest hazard ratios (HRs) for the three PS quintiles-adjusted models were obtained by a cutoff of treatment initiation within 1 year from disease onset. Early treatment significantly reduced the risk of reaching a 1-point progression in EDSS score (HR = 0.63; 95% CI = 0.48-0.85; p < 0.002), and the EDSS 4.0 milestone (HR = 0.56; 95% CI = 0.36-0.90; p = 0.015). Sensitivity analysis showed the bound of significance for unmeasured confounders. INTERPRETATION: Greater benefits on disability progression may be obtained by an early IFNbeta treatment in RRMS.

Post-marketing of disease modifying drugs in multiple sclerosis: an exploratory analysis of gender effect in interferon beta treatment.

BACKGROUND: There are a few and conflicting results from randomised controlled trials (RCTs) pertaining to the influence of gender in response to currently used disease modifying drugs in Multiple Sclerosis (MS). Observational studies may be especially valuable for answering effectiveness questions in subgroups not studied in RCTs. OBJECTIVE: To conduct a post-marketing analysis aimed to evaluate the gender effect on Interferon beta (IFNbeta) treatment response in a cohort of relapsing (RR) MS patients. METHODS: A cohort of 2570 IFNbeta-treated RRMS was prospectively followed for up to 7 years in 15 Italian MS Centers. Cox proportional hazards regression models were used to assess gender differences for risk of reaching 1st relapse and risk of progression by 1 point on Expanded Disability Status Scale (EDSS) score. Gender effects were also explored by a propensity score (PS) matching algorithm, and a tree-growing technique. RESULTS: The multivariate Cox Regression analyses showed that male patients had a significant (p=0.0097) lower risk for 1st relapse and a trend (p=0.0897) for a higher risk to reach 1 point EDSS progression than females. The PS matched multivariate Cox Regression confirmed these results. The RECPAM analysis showed that male sex conferred a significant reduction in the risk for 1st relapse (HR=0.86; 95% CI=0.76-0.98; p=0.0226) in the subgroup with a low pre-treatment number of bouts, and a significant increase in the risk for 1 point EDSS progression (HR=1.33; 95% CI: 1.00-1.76; p<0.05) in the subgroup with a delayed treatment, but a still young age at the start of treatment. CONCLUSION: The results of this exploratory analysis seem to suggest that male patients do not respond to IFNbeta treatment in the same way of females.

Vestibular rehabilitation and 6-month follow-up using objective and subjective measures.

CONCLUSIONS: Vestibular rehabilitation improves quality of life by reducing the degree of handicap, improving the ability to perform everyday tasks and providing long-term rehabilitation stability (at 6 months). Recovery of the vestibulo-ocular reflex and the vestibulo-spinal reflex efficiency was proven by the objective results obtained in this study. Vestibular rehabilitation improves both subjective and objective parameters, although no significant correlation between these two indices was found. OBJECTIVE: To determine the outcome of subjective and objective parameters and long-term rehabilitation stability after vestibular rehabilitation in 43 patients with vestibular disorders. MATERIAL AND METHODS: The subjective tests used were the Medical Outcomes Study 36-item Short Form, the Dizziness Handicap Inventory and the Activity-specific Balance Confidence scale. The objective tests used were video-oculoscopy, dynamic visual acuity, the Equitest and the Dynamic Gait Index. All indices were evaluated before and after rehabilitation and at follow-up. RESULTS: All patients showed an improvement in quality of life and a reduction in handicap due to dizziness. Improvement in objective test results was also seen. These results were stable at follow-up. A correlation was found between different subjective measures, but there was no correlation between subjective and objective measures.

Glatiramer acetate induces pro-apoptotic mechanisms involving Bcl-2, Bax and Cyt-c in peripheral lymphocytes from multiple sclerosis patients.

Apoptotic deletion of autoreactive T-cells is defective in patients with multiple sclerosis (MS). Glatiramer acetate (GA) treatment seems to restore apoptosis of detrimental T-cells. We analyzed the mitochondria membrane pro- (Bax) and anti-apoptotic (Bcl- 2) and cytosolic pro-apoptotic (Cyt-c, APAF-1) proteins expression in peripheral lymphocytes from relapsing-remitting (RR) MS patients during GA treatment. Blood samples were collected from 8 healthy controls (HCs) and from 8 RR MS patients prior to and every three months during the 9 months of GA treatment. Peripheral blood mononuclear cells (PBMNCs) Bcl-2, Bax, Cyt-c and APAF-1 were quantified by western blot followed by densitometric scanning and Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios were calculated. T-cells were in vitro tested for oxygen consumption by a respirometric analysis. Bax/Bcl-2, cytosolic Cyt-c/Bcl-2 and APAF-1/Bcl-2 ratios in untreated MS patients were significantly (p < 0.05) lower than in HCs. Bax/Bcl-2 ratio increased (p = 0.03) and Cyt-c/Bcl-2 ratio showed a trend to increase during the 9 months of GA treatment in MS patients. A reduction of 58% and 59% in oxygen consumption by PBMNCs was evident after GA treatment in vitro or when GA treated patients' cells were compared with those from HCs, respectively. Our findings suggest that GA exerts a regulatory effect on peripheral T lymphocytes through pro-apoptosis mechanisms involving mitochondria and cytosolic proteins.

The IFNbeta treatment of multiple sclerosis (MS) in clinical practice: the experience at the MS Center of Bari, Italy.

This independent, population-based surveillance study monitored, in clinical practice, the efficacy of interferon beta (IFNbeta) products in 1173 patients with multiple sclerosis (MS) from the Department of Neurological and Psychiatric Sciences, University of Bari, Italy. Relapses and Expanded Disability Status Scale (EDSS) scores were evaluated for up to 6 years for Avonex, Betaferon and Rebif 22 groups, and for up to 3 years for the Rebif 44 group. IFNbeta products produced significant reductions from baseline in relapse rates at 2, 4 and >4 years (p<0.0001), with no differences among treatments (p=0.2). A modest significant (p<0.05) increase of EDSS was observed in all treatment groups from baseline to 48 months, followed thereafter by a plateau. The IFNbeta-1b group showed more withdrawals (19%) compared with Avonex (6%) and Rebif (7%) at 6 years.

Revealing deterministic structures in click-evoked otoacoustic emissions.

Click-evoked otoacoustic emissions (CEOAEs) were studied by means of recurrence quantification analysis (RQA) and were found to be endowed with a relevant amount of deterministic structuring. Such a structure showed highly significant correlation with the clinical evaluation of the signal over a data set including 56 signals. Moreover, 1) one of the RQA variables, Trend, was very sensitive to phase transitions in the dynamical regime of CEOAEs, and 2) appropriate use of principal component analysis proved able to isolate the individual character of the studied signals. These results are of general interest for the study of auditory signal transduction and generation mechanisms.

Age at onset in multiple sclerosis.

Age at onset of multiple sclerosis (MS) can vary from childhood to adult life. Many reports have been carried out over the years concerning the role of age at onset in determining the disease outcome. In a sporadic MS population of 1463 patients with homogeneous clinical and demographic features, derived from three Italian neurological centres (Bari, Cagliari and Sassari), we analysed the relative weights of current age and age at onset on disease severity according to the expanded disability status scale (EDSS) score, by fixing the disease duration. The results of present study demonstrate that clinical disability in MS is influenced by the patient's age (p < 0.01) and not by the age at onset. Therefore, these data do not confirm the hypothesis that an early age at onset should be considered a favourable prognostic factor of the disease outcome.

Reduced concentrations of HIV-RNA and TNF-alpha coexist in CSF of AIDS patients with progressive multifocal leukoencephalopathy.

OBJECTIVES: To confirm reduced human immunodeficiency virus type-1 (HIV-1) burden in the CSF of patients with progressive multifocal leukoencephalopathy (PML) and to verify whether this viral load coincides with the absence of inflammatory changes in the CSF. METHODS: Paired CSF and plasma samples from 17 patients with PML, 26 with non-PML cerebral opportunistic infections, nine with HIV-1 leukoencephalopathy (HIVE), and 12 neurologically asymptomatic AIDS patients were subjected to HIV-RNA titration. Tumour necrosis factor (TNF)-alpha was also measured and the CSF albumin: serum albumin ratio (Q(Alb)) was calculated. RESULTS: The CSF HIV-1 burden of patients with PML did not differ from that of neurologically asymptomatic patients (p=0.21), but was significantly lower than CSF burden of the remaining patients (non-PML opportunistic infections, p<0.001; HIVE, p<0.001). Q(Alb) was normal for all neurologically asymptomatic patients, for 86.6% patients with PML, and 62.5% patients with HIVE (p=0.09). Q(Alb) was altered in 91.6% patients with non-PML opportunistic infections. TNF-alpha in CSF was higher in patients with non-PML opportunistic infections (p<0.001) and those with HIVE (p<0.001) than in patients with PML who consistently had TNF-alpha concentrations<10 pg/ml. CONCLUSIONS: These results, while indicating a reduced HIV replication in CSF of patients with PML which might serve as a disease marker, emphasise the increased CSF HIV-RNA concentration in patients with HIVE and patients with non-PML opportunistic infections. Low concentrations of HIV-RNA in CSF coincide with reduced TNF-alpha concentrations, possibly due to particular features of PML compared with other opportunistic infections as it develops without detectable inflammatory changes in the CSF.

Localised 1H-MR spectroscopy for metabolic characterisation of diffuse and focal brain lesions in patients infected with HIV.

OBJECTIVES: To evaluate the role of proton MR spectroscopy (1H-MRS) in detecting metabolic changes in diffuse or focal lesions in the brain of patients infected with HIV. METHODS: Sixty HIV seropositive patients (25 with HIV related encephalopathies, 20 with toxoplasmosis, eight with progressive multifocal leukoencephalopathies (PMLs), and seven with lymphomas) and 22 HIV seronegative neurological controls were examined with a combined MRI and 1H-MRS technique using a Siemens 1.5 Tesla Magnetom. Spectra (Spin Echo sequence, TE 135 ms) were acquired by single voxel, localised on focal lesions in toxoplasmosis, PML, lymphomas, and HIV encephalopathies and on the centrum semiovale of neurological controls. Choline (Cho), creatine (Cr), N-acetyl aspartate (NAA), lactate, and lipids were evaluated in each spectrum and NAA/Cr, NAA/Cho, and Cho/Cr ratios were calculated. RESULTS: A significant decrease in NAA/Cr and NAA/Cho ratios were found in all HIV diagnostic groups in comparison with neurological controls (p<0.003), suggesting neuronal or axonal damage independent of brain lesion aetiology. However, the NAA/Cr ratio was significantly lower in PML and lymphomas than in HIV encephalopathies (p<0.02) and toxoplasmosis (p<0.05). HIV encephalopathies, lymphomas, and toxoplasmosis showed a significant increase in the Cho/Cr ratio in comparison with neurological controls (p<0.03) without between group differences. The presence of a lipid signal was more frequent in lymphomas (71%) than in other HIV groups (Fisher's test, p=0.00003). The presence of mobile lipid resonance together with a high Cho/Cr ratio in lymphomas may be related to an increased membrane synthesis and turnover in tumour cells. A lactate signal (marker of inflammatory reaction), was found in all but one patient with PML lesions (75%), but had a lower incidence in the other HIV diagnostic groups (Fisher's test, p=0.00024). CONCLUSION: 1H-MRS shows a high sensitivity in detecting brain involvement in HIV related diseases, but a poor specificity in differential diagnosis of HIV brain lesions. Nevertheless, the homogeneous metabolic pattern that characterises PML suggests the usefulness of 1H-MRS as an adjunct to MRI in differentiating CNS white matter lesions, such as HIV encephalopathies, from PML.

Measurement of viral sequences in cerebrospinal fluid of AIDS patients with cerebral white-matter lesions using polymerase chain reaction.

OBJECTIVES: To optimize the use of polymerase chain reaction (PCR) on cerebrospinal fluid (CSF) for the evaluation of central nervous system (CNS) white-matter lesions that along with clinical findings and magnetic resonance imaging (MRI) can allow a definite diagnosis to be made; also to evaluate treatment with zidovudine plus foscarnet. DESIGN AND METHODS: Fifteen AIDS patients with uncertain CNS white-matter lesions were identified. HIV-1 RNA, cytomegalovirus (CMV) and JC virus (JCV) DNA were measured in a total of 29 CSF samples. The results were correlated with clinical and MRI findings and treatment with zidovudine plus foscarnet was evaluated. RESULTS: Four and five out of 15 patients with CMV DNA > or = 1 : 625 and JCV DNA > or = 10(3) copies/microl detected in the CSF were diagnosed with CMV and progressive multifocal leukoencephalopathy (PML), respectively. Six patients who were CMV/JCV-negative with the highest levels of HIV RNA (median, 6.87 log10 copies/ml) in CSF were considered as having HIV-1 encephalitis. Neurological symptoms were non-supportive for diagnosis as was MRI in 11 out of 15 patients. Nine patients completed a 21-day course of zidovudine plus foscarnet. HIV RNA decreased irrespective of neurological diagnosis. All three HIV-1 encephalitis patients and two out of three patients with CMV leukoencephalopathy improved. In these two latter patients, relief of clinical symptoms coincided with decreased CMV DNA. JCV DNA remained unchanged and all three PML patients deteriorated. CONCLUSIONS: Measurement of CSF viral sequences supports the diagnosis of CNS white-matter lesions in AIDS patients. While effective therapy for PML remains elusive, treatment including zidovudine plus foscarnet may be a promising option for HIV-1 and CMV-related manifestations.

The essential dynamics of Cu, Zn superoxide dismutase: suggestion of intersubunit communication.

A 300-ps molecular dynamics simulation of the whole Cu, Zn superoxide dismutase dimer has been carried out in water, and the trajectory has been analyzed by the essential dynamics method. The results indicate that the motion is defined by few preferred directions identified by the first four to six eigenvectors and that the motion of the two monomers at each instant is not symmetrical. The vectors symmetrical to the eigenvectors are significantly sampled, suggesting that, on average, the motions of the two subunits will exchange. Large intra- and intersubunit motions involving different subdomains of the protein are observed. A mechanical coupling between the two subunits is also suggested, because displacements of the loops surrounding the active site in one monomer are correlated with the motion of parts of the second toward the intersubunit interface.

Conductometric properties of human erythrocyte membranes: dependence on haematocrit and alkali metal ions of the suspending medium.

The electrical properties of the cytoplasmatic membrane of human erythrocyte cells have been evaluated by means of dielectric spectroscopy measurements in the radiowave frequency range, using the so-called "suspension method". Measurements have been carried out at different volume fractions of the corpuscular phase (the cell haematocrit) in order to investigate the influence of the cell-cell interactions on the electrical parameters (the membrane permittivity epsilon and the membrane conductivity sigma) of the cell membrane and a set of new values are proposed. Moreover, the influence of different alkali metal ions (Na+, K+, Cs+, Li+) on the ion permeation properties of the membrane are investigated and the structural alterations in the membrane organized briefly discussed.

Use of low-frequency electrical impedance measurements to determine phospholipid content in amniotic fluid.

In this report we propose a new method for an in vitro test of the foetal lung maturity based on the measurement of the electrical conductivity of the overall amniotic fluid obtained from transabdominal amniocentesis, since this quantity can be linked to a first approximation in a very simple way to the phospholipid content. We have carried out measurements of 85 different samples of amniotic fluid as a function of gestation weeks and we have observed a pronounced change of the electrical conductivity that reflects the increase in the phospholipid concentration occurring at the end of normal pregnancies. The method could be further developed to obtain similar information on in vivo experiments by means of bioelectric impedance tomography, taking advantage of the frequency dependence of the tissue electrical impedance.

Choreoathetosis in acquired immune deficiency syndrome patients with cerebral toxoplasmosis.

The aim of our study was to evaluate both the incidence and the pathologic and clinical features of extrapyramidal disorders in a population of acquired immune deficiency syndrome (AIDS) patients with cerebral toxoplasmosis. Of 240 AIDS patients evaluated in the 1985-1994 period, 50 of them were diagnosed to have cerebral toxoplasmosis on the basis of the following criteria: occurrence of specific antibodies, computed tomography and/or magnetic resonance imaging (MRI), and regression of the symptoms after specific therapy. Three of 50 (6%) had hemichoreoathetosis. In the first case, the disorder began as a dyskinesia of the left hand that subsequently spread to the whole ipsilateral arm and assumed the features of choreic athetotic movements. The other two cases were characterized by left hemisomatic distal choreic movements. Therapy with pyrimethamine and sulfadiazine led to a complete recovery of the extrapyramidal signs in two cases and to improvement in the third. According to our observations, the onset of these movement disorders could not be related to the dimension of the lesion or to the edema, but to a specific localization in subthalamic nucleus, in subthalamic/pallidal, and pallidal/thalamic pathways. MRI seems the elective tool to perform a more accurate study of the anatomic areas involved in this pathway and to verify their integrity. Cerebral toxoplasmosis in AIDS can be considered as a new etiopathogenic cause of choreoathetosis.

Relevance of intravenous cocaine use in relation to prevalence of HIV, hepatitis B and C virus markers among intravenous drug abusers in southern Italy.

The purpose of this study was to analyze the relationship between intravenous (i.v) drug use practices and the prevalence of human immunodeficiency virus (HIV), hepatitis B virus (HBV) and hepatitis C virus (HCV) in 146 heterosexual male i.v. drug users (IVDUs) attending a methadone-maintainance treatment program in Catanzaro, Southern Italy. One hundred and forty-six heterosexual male IVDUs attending a methadone-maintainance treatment program in Catanzaro were interviewed in order to obtain the following information: age, number of drug injections (calculated by multiplying the mean number of daily injections by 365 and then by the number of years of injections), number of injection equipment-sharing partners in the last year, number of sexual partners in the last year and possible IV cocaine use. Their sera were studied for the presence of antibodies to HIV, HBV and HCV by commercial enzyme-linked-immuno-sorbent assays run in duplicate. HIV positive samples were confirmed by Western Blot assay. Sixteen per cent of IVDUs were anti-HIV positive, 40% were anti-HBc positive and 68% were anti-HCV positive. Twenty-three per cent were seronegative and 12% were seropositive for all 3 viral markers. Multiple logistic analysis of HIV, HBV and HCV seropositivities in relation to age, number of drug injections, i.v. cocaine use and presence of injection equipment-sharing partners in the last year, showed that: a) older age (more than 27 years) was significantly associated with all 3 viral infections (mainly with HIV); b) i.v. cocaine use was associated with HBV, but even more with HIV; c) injection equipment-sharing partners in the last year was directly associated with HCV and inversely with HIV. No significant association was observed with the number of drug injections and the number of sexual partners. In conclusion, this study: a) demonstrates a difference of prevalence for HIV, HBV and HCV serum markers in this group of IVDUs from Catanzaro, Southern Italy; b) underlines the importance of i.v. cocaine use in the spreading of HIV; c) emphasizes the need of preventive strategies.

A dielectric relaxation study on the effects of the antitumor drugs Lonidamine and Rhein on the membrane electrical properties of Ehrlich ascites tumor cells.

The effects of the anti-tumor drugs lonidamine and rhein on the plasma membrane electrical properties of Ehrlich ascites tumor cells were investigated and compared. Dielectric relaxation measurements in the radiowave frequency range (10(4) to 10(8) Hz) as well as at higher frequencies (10(4) to 10(9) Hz) were performed and the data elaborated using a "single-shell" fitting procedure. The results obtained in both frequency ranges indicate that membrane conductivity and membrane permittivity are altered by 200 microM Lonidamine while 150 microM rhein induces only very slight variations in these two plasma membrane parameters. The usefulness of the dielectric relaxation technique described here in evaluating antitumor drugs and improving clinical protocols is discussed.

Anti-hepatitis C antibody prevalence among intravenous drug addicts in the Catanzaro area.

A higher seroprevalence of anti-HCV antibodies (63.4%) was found in 41 intravenous drug addicts (IVDA) when compared to 220 controls (1.8%). Life style is an important risk factor for HCV transmission among IVDA.

Different biological properties of paired HIV-1 isolates from peripheral blood mononuclear cells and cerebrospinal fluid.

Seven paired HIV-1 isolates from peripheral blood mononuclear cells (PMCs) and cerebrospinal fluid (CSF) of infected subjects at various stages of the disease were studied for their capacity to replicate in continuous cell lines (Molt-3 and U-937 cells) and to induce cytopathic effects "in vitro". Obtained results indicate that paired HIV-1 isolates from PMCs and CSF of the same patient can differ in their replicative activity "in vitro", suggesting that, at least in some cases, CSF isolates may represent a distinct subtype of HIV-1.