Showing papers by "University of Bologna published in 1994"

Cerebrospinal fluid in the diagnosis of multiple sclerosis: a consensus report.

Abstract: The Committee of the European Concerted Action for Multiple Sclerosis (Charcot Foundation) organised five workshops to discuss CSF analytical standards in the diagnosis of multiple sclerosis. This consensus report from 12 European countries summarises the results of those workshops. It is hoped that neurologists will confer with their colleagues in clinical chemistry to arrange the best possible local practice. The most sensitive method for the detection of oligoclonal immunoglobulin bands is isoelectric focusing. The same amounts of IgG in parallel CSF and serum samples are used and oligoclonal bands are revealed with IgG specific antibody staining. All laboratories performing isoelectric focusing should check their technique at least annually using "blind" standards for the five different CSF and serum patterns. Quantitative measurements of IgG production in the CNS are less sensitive than isoelectric focusing. The preferred method for detection of blood-CSF barrier dysfunction is the albumin quotient. The CSF albumin or total protein concentrations are less satisfactory. These results must be interpreted with reference to the age of the patient and the local method of determination. Cells should be counted. The normal value is no more than 4 cells/microliters. Among evolving optional tests, measurement of the combined local synthesis of antibodies against measles, rubella, and/or varicella zoster could represent a significant advance if it offers higher specificity (not sensitivity) for identifying chronic rather than acute inflammation. Other tests that may have useful correlations with clinical indices include those for oligoclonal free light chains, IgM, IgA, or myelin basic protein concentrations.

Malignancies in fibrous dysplasia.

Abstract: collected in the literature. Most of the descriptions of sarcomas in fibrous dysplasia that are in the literature are single case reports or reports of a few case^.^-'^ The largest series, which includes 15 cases, is that from Memorial Sloan-Kettering Cancer Center, New York.2,20 In 1988, Yabut and coworkers' reported a new case and found 83 cases in a careful review of the literature. The most common of the malignancies was osteosarcoma, followed by fibrosarcoma and chondrosarcoma. The possibility of sarcomatous change in fibrous dysplasia without prior irradiation seems well established, as verified by several reports of documented case~.~~~~'' The role of radiation therapy in the occurrence of sarcoma in fibrous dysplasia is still c~ntroversial.'~~~~' In Huvos' series," only 1 of 15 patients with sarcomas in fibrous dysplasia had received radiation therapy. In the review of the literature by Yabut and coworker^,^ 23 patients had received radiation therapy, 46 had not had prior irradiation, and 14 did not have information available. The purpose of the current study was to review and report our experience with malignancies in fibrous dysplasia. Materials and Methods

Diabetes and the Risk of Pancreatic-cancer

Abstract: Summary Aims: Diabetes occurs more frequently in patients with pancreatic cancer than in the general population, and it has repeatedly been claimed that it is a risk factor for this tumor. However in most of the studies on this subject the duration of diabetes before the diagnosis of pancreatic cancer was not ascertained. In an attempt to clarify the cause of the association between these two pathologic conditions and to determine whether diabetes is a risk factor for pancreatic cancer we recently studied this association in a large number of patients with pancreatic cancer. Methods: A total of 720 patients with newly diagnosed pancreatic cancer (415 men and 305 women; mean age 62.6 years, range 22 to 79 years) and 720 controls matched for sex, age, social class, and geographic region, were enrolled in the study. All subjects were interviewed personally and in detail about their clinical history. The diagnosis of diabetes was based on criteria recommended by the American Diabetes Association. Results: One hundred sixty-four patients with pancreatic cancer (22.8 %) and 60 controls (8.3 %) had diabetes. In the majority of the patients with pancreatic cancer (56.1 %), diabetes was diagnosed either concomitantly with the cancer (in 40.2 %), or within two years before the diagnosis of cancer (in 15.9 %). The association between the two conditions was significant (odds ratio, 3.04; 95 % confidence interval, 2.21 to 4.17). However, when only patients with diabetes of three or more years' duration were considered, the association was no longer significant (odds ratio, 1.43; 95 % confidence interval, 0.98 to 2.07). All the patients with pancreatic cancer whose diabetes had been diagnosed before the cancer had non-insulin-dependent diabetes; all but one of the control patients with diabetes had the non-insulin-dependent form of the disease. Conclusions: Diabetes in patients with pancreatic cancer is frequently of recent onset and is presumably caused by the tumor. Diabetes is not a risk factor for pancreatic cancer.

Fatal familial insomnia and familial Creutzfeldt-Jakob disease: different prion proteins determined by a DNA polymorphism.

Abstract: Fatal familial insomnia and a subtype of Creutzfeldt-Jakob disease, two clinically and pathologically distinct diseases, are linked to the same mutation at codon 178 (Asp-178-->Asn) but segregate with different genotypes determined by this mutation and the methionine-valine polymorphism at codon 129 of the prion protein gene. The abnormal isoforms of the prion protein in these two diseases were found to differ both in the relative abundance of glycosylated forms and in the size of the protease-resistant fragments. The size difference was consistent with a different protease cleavage site, suggesting a different conformation of the protease-resistant prion protein present in the two diseases. These differences are likely to be responsible for the type and location of the lesions that characterize these two diseases. Therefore, the combination of the mutation at codon 178 and the polymorphism at codon 129 determines the disease phenotype by producing two altered conformations of the prion protein.

Cognitive behavioral treatment of residual symptoms in primary major depressive disorder.

Abstract: Objective Cognitive behavioral treatment has been used extensively in the acute phase of depression. The purpose of this study was to determine the applicability and effectiveness of this treatment modality in addressing the residual symptoms of primary major depressive illness. Method The subjects were 40 patients with major depressive disorder who were successfully treated with antidepressant drugs. They were then randomly assigned to either cognitive behavioral treatment or clinical management of residual symptoms. In both subgroups, antidepressant drugs were tapered and discontinued. Results The group that received cognitive behavioral treatment had a significantly lower level of residual symptoms after drug discontinuation in comparison with the clinical management group. Cognitive behavioral treatment also resulted in a lower rate of relapse (15%) at a 2-year follow-up than did clinical management (35%), although this difference did not reach statistical significance. Most of the residual symptoms were found to have occurred also in the prodromal phase of illness. Conclusions This preliminary study points to the potential clinical advantages of cognitive behavioral treatment targeted to the residual symptoms of depression.

Modular uncemented prosthetic reconstruction after resection of tumours of the distal femur

Abstract: We report the use of the uncemented Kotz modular femur and tibia reconstruction system after 95 distal femoral resections performed from 1983 to 1989. The average follow-up was 51 months; 62 patients had at least 36 months' follow-up and 36 at least 60 months. Complications required reoperation in 55%. The postoperative infection rate was 5% for primary cases, 6% for revision cases, and 43% for revision of previously infected cases. The polyethylene bushes failed in 42% of cases at an average of 64 months postoperatively. Stem breakage occurred in 6% and was associated with the use of narrow stems and extensive quadriceps excision. The radiological results were excellent or good in most cases and were related to the initial screw fixation, but not to age, chemotherapy, length of resection or size of stem. The clinical results were excellent or good in 75%, failure usually being associated with a complication, especially infection.

Natural substances (acetogenins) from the family Annonaceae are powerful inhibitors of mitochondrial NADH dehydrogenase (Complex I).

Abstract: Natural products from the plants of the family Annonaceae, collectively called Annonaceous acetogenins, are very potent inhibitors of the NADH-ubiquinone reductase (Complex I) activity of mammalian mitochondria. The properties of five of such acetogenins are compared with those of rotenone and piericidin, classical potent inhibitors of Complex I. Rolliniastatin-1 and rolliniastatin-2 are more powerful than piericidin in terms of both their inhibitory constant and the protein-dependence of their titre in bovine submitochondrial particles. These acetogenins could be considered therefore the most potent inhibitors of mammalian Complex I. Squamocin and otivarin also have an inhibitory constant lower than that of piericidin, but display a larger protein-dependence of the titre. Squamocin and otivarin, contrary to the other acetogenins, behave qualitatively like rotenone. Rolliniastatin-2 shows unique properties as its interaction, although mutually exclusive to that of piericidin, appears to be mutually non-exclusive to that of rotenone. It is the first time that a potent inhibitor of Complex I is found not to overlap the active site of rotenone.

The UK Consumption Boom of the Late 1980s: Aggregate Implications of Microeconomic Evidence

Abstract: Two competing explanations of the UK consumer boom in the late 1980s are the financial liberalisation-imperfect housing market hypothesis of Muellbauer and Murphy and the expectations hypothesis of King. We use 15 years of Family Expenditure Surveys, and cohort analysis, to investigate to what extent these two hypotheses agree with observed changes in consumption patterns. We find that the housing markets explanation accounts for much of the increase by older cohorts, but cannot be reconciled with the marked rise in expenditure levels of younger households. A simple simulation exercise shows instead that the expectations hypothesis can generate increases of expenditure by young consumers of the magnitude observed in our data.

Arc-furnace model for the study of flicker compensation in electrical networks

Abstract: This paper presents an arc-furnace model consisting of nonlinear, time varying resistance where time-variation laws of arc length are considered. One consists of a periodic, sinusoidal law, the other of a band-limited white-noise law. The arc-furnace model is implemented by EMTP, referring to actual electric-plant configurations. Simulations are reported where the values of flicker sensation and short-term flicker severity P/sub ST/, are determined according to UIE specifications. The results show that the model based on the sinusoidal time-variation law can be useful for worst-case approximations, while the model using white-noise law is able to fit flicker measurements made in electric plants supplying arc furnaces. The models are used to investigate the effect on flicker compensation of the insertion of series inductors at the supply side of the furnace transformer. It is shown that considerable reduction of P/sub ST/ is obtained at the point of common coupling by series inductor installation at constant furnace active power. >

Band heterotopia : correlation of outcome with magnetic resonance imaging parameters

Abstract: The "band heterotopia" or "double cortex" is a brain anomaly that is presumed to result from a premature arrest of neuronal migration. Patients with this anomaly are reported to have a variable clinical course that has been, heretofore, unpredictable. The clinical records and magnetic resonance (MR) imaging studies of 27 patients with band heterotopia were retrospectively reviewed in an attempt to determine whether imaging findings are useful in predicting clinical outcome of affected patients. Statistical analyses revealed the following correlations: (1) severity of T2 prolongation in the brain with motor delay (p = 0.03); (2) degree of ventricular enlargement with the age of seizure onset (p = 0.04), and with development and intelligence (p = 0.04); (3) severity of pachygyria with the age of seizure onset (p = 0.01), seizure type (p = 0.03), and an abnormal neurologic examination (p = 0.002); (4) parietal involvement with delayed speech development (p = 0.05); (5) occipital involvement with age of seizure onset (p = 0.006); (6) age of seizure onset with development and intelligence (p = 0.03) and with an abnormal neurologic examination (p = 0.04); and (7) severity of the pachygyria and thickness of band with development of symptomatic generalized epilepsy (p = 0.002 and p = 0.02, respectively) and Lennox-Gastaut syndrome (p = 0.002 and p = 0.01, respectively).

General noise analysis of nonlinear microwave circuits by the piecewise harmonic-balance technique

Abstract: This paper presents a self-consistent set of algorithms for the numerical computation of noise effects in forced and autonomous nonlinear microwave circuits. The analysis relies upon the piecewise harmonic-balance method, and thus retains all the peculiar advantages of this technique, including general-purposeness in the widest sense. The noise simulation capabilities include any kind of forced or autonomous nonlinear circuit operated in a time-periodic large-signal steady state, as well as microwave mixers of arbitrary topology. The limitations of the traditional frequency-conversion approach to noise analysis are overcome. The analysis takes into account the thermal noise generated in the passive subnetwork, the noise contributions of linear and nonlinear active devices, and the noise injected by sinusoidal driving sources of known statistical properties. The nonlinear noise models of two representative families of microwave devices (FET's/HEMT's and Schottky-barrier diodes) are discussed in detail, and several applications are illustrated. >

Eastern segment of the Azores-Gibraltar line (central-eastern Atlantic) : An oceanic plate boundary with diffuse compressional deformation

Abstract: New seismic-reflection images across the eastern segment of the Azores-Gibraltar line west of the collisional area between the African and Iberian plates have revealed a complex pattern of compressional deformation involving the Mesozoic oceanic lithosphere. The compressional deformation developed in a region of slow plate convergence and is diffused, at different lithospheric levels, across an area spanning ∼200 km from the Gorringe Ridge to the Seine Plain. The convergence between the African and Iberian plates has been active since Tertiary time, and our results indicate that no subduction zone exists across this part of the plate boundary.

An algorithm for the minimization of mixed l/sub 1/ and l/sub 2/ norms with application to Bayesian estimation

Abstract: The regularizing functional approach is widely used in many estimation problems. In practice, the solution is defined as one minimum point of a suitable functional, the main part of which accounts for the underlying physical model, whereas the regularizing part represents some prior information about the unknowns. In the Bayesian interpretation, one has a maximum a posteriori (MAP) estimator in which the main and regularizing parts are represented, respectively, by likelihood and prior distributions. When either the prior or likelihood is a Laplace distribution and the other is a Gaussian distribution, one is led to consider functionals that include both absolute and square norms. The authors present a characterization of the minimum points of such functionals, together with a descent-type algorithm for numerical computations. The results of Monte-Carlo simulations are also reported. >

Weighted Sobolev-Poincaré inequalities for Grushin type operators

Abstract: (1994). Weighted sobolev-poincare inequalities for grushin type operators. Communications in Partial Differential Equations: Vol. 19, No. 3-4, pp. 523-604.

Compensation strategies for shunt active-filter control

Abstract: Compensation strategies for control of shunt active filters are compared in the paper. It is shown that the strategy based on unity-power factor control is appropriate when the supply voltage waveform of the plant where the active filter is connected shows significant distortion. As voltage distortion increases, this strategy provides compensated line current having lower harmonic distortion and RMS value with respect to the strategy generally used. This contributes to diminish the current and voltage distortion in networks. The unity-power factor compensation strategy conditions the current flowing in the plant where compensation is realized to fit the voltage waveform, thus reaching a unity power factor. Hence, the line current RMS value is minimum. The comparison of the strategies is performed by both Monte Carlo and ATP simulation. >

Effects of flux and torque hysteresis band amplitude in direct torque control of induction machines

Abstract: Direct torque control of induction machines allows high dynamic performance to be obtained utilising a simple signal processing method. Furthermore, this control technique does not require current regulators so reducing the hardware requirements. In this paper, the influence of the amplitude of flux and torque hysteresis bands on switching frequency, torque and flux ripple, current distortion and drive losses is investigated. The advantages of a careful choice of hysteresis band amplitudes are emphasised. The numerical results are verified by experimental tests carried out on a DSP based processing system. >

An Antimatter spectrometer in space

Abstract: We discuss a simple magnetic spectrometer to be installed on a satellite or space station. The purpose of this spectrometer is to search for primordial antimatter to the level of antimatter/matter ≈10 −9 , improving the existing limits obtained with balloon flights by a factor of 10 4 to 10 5 . The design of the spectrometer is based on an iron-free, NdFeB permanent magnet, scintillation counters, drift tubes, and silicon or time projection chambers. Different design options are discussed. Typically, the spectrometer has a weight of about 2 tons and an acceptance of about 1.0 m 2 sr. The availability of the new NdFeB material makes it possible for the first time to put a magnet into space economically and reliably.

Deflazacort in Duchenne dystrophy: Study of long‐term effect

Abstract: A randomized double-blind controlled trial of deflazacort was conducted in 28 Duchenne muscular dystrophy patients either treated with deflazacort 2.0 mg/kg alternate-day therapy or placebo. The deflazacort group showed significant improvement in climbing stairs (P < 0.01), in rising from a chair, Gower's maneuver, and walking (P < 0.0025) after 6 months of treatment. After 1 year, all the above changes remained significantly improved and the MRC index was significantly better (P < 0.05) in the treated group. After 2 years, a significant change was found in the MRC index: higher scores in walking, chair rising (P < 0.02), and grade and time of Gower's maneuver (P < 0.05) were found. The mean time for loss of ambulation for the treated group after we started the trial was 33.2 +/- 9 months; for the placebo group it was 20.5 +/- 11 months (deflazacort vs. placebo group, P < 0.05) [corrected]. Our treated patients lost their ambulation at a median age of 11.8 years vs. 10.5 years in the placebo group. Side effects were mild, consisting of moderate weight gain and slight behavioral changes.

Drug-induced hair loss and hair growth. Incidence, management and avoidance.

Abstract: A large number of drugs may interfere with the hair cycle and produce hair loss. Drugs may affect anagen follicles through 2 main different modalities: (i) by inducing an abrupt cessation of mitotic activity in rapidly dividing hair matrix cells (anagen effluvium) or (ii) by precipitating the follicles into premature rest (telogen effluvium). In anagen effluvium, hair loss usually occurs within days to weeks of drug administration, whereas in telogen effluvium, hair loss becomes evident 2 to 4 months after starting treatment. Anagen effluvium is a prominent adverse effect of antineoplastic agents, which cause acute damage of rapidly dividing hair matrix cells. Telogen effluvium may be a consequence of a large number of drugs including anticoagulants, retinol (vitamin A) and its derivatives, interferons and antihyperlipidaemic drugs. Drug-induced hair loss is usually reversible after interruption of treatment. The prevalence and severity of alopecia depend on the drug as well as on individual predisposition. Some drugs produce hair loss in most patients receiving appropriate dosages while other drugs are only occasionally responsible for hair abnormalities. Both hirsutism and hypertrichosis may be associated with drug administration. Drugs most commonly responsible for the development of hirsutism include testosterone, danazol, corticotrophin (ACTH), metyrapone, anabolic steroids and glucocorticoids. Hypertrichosis is a common adverse effect of cyclosporin, minoxidil and diazoxide.

FLAG (fludarabine + high-dose cytarabine + G-CSF): an effective and tolerable protocol for the treatment of 'poor risk' acute myeloid leukemias.

Abstract: Twenty-eight patients with poor prognosis acute myeloid leukemia (AML) received therapy with two courses of fludarabine 30 mg/m2/day + ara-C 2 g/m2/day (days 1-5) and G-CSF 5 mg/kg/day (FLAG) (from day 0 to polymorphonuclear recovery). Eighteen patients were considered 'refractory' (eight primarily resistant, five relapsing within 6 months of initial remission, or at a second relapse; five relapsing after an autologous bone marrow transplantation procedure. Ten cases were defined 'secondary' AML (diagnosis of AML made after a preexisting diagnosis of: myelodysplastic syndrome: five cases; myelodysplastic syndrome after therapy for breast cancer: one case; previously untreated, and concomitant, non-Hodgkin's lymphoma: two cases; Hodgkin's disease treated with chemoradiotherapy: one case). Overall, 15 patients (58%) achieved a complete remission (CR). Two patients died of infection during induction, and 11 had resistant disease. Analyzing the data in relation to selected host and disease characteristics, the response varied widely. The highest CR rates (89%) were obtained in secondary AML; in particular, two cases of 'second-primary' (concomitant with low-grade non-Hodgkin's lymphoma) AML obtained CR for both diseases. Refractory AML differed widely for response: high CR rate (75%), although with short mean CR duration for primary resistance AML, and very poor response (11% CR) for relapsed (early, second, after ABMT) cases. Interestingly, a slow kinetic of leukemic growth in vivo before FLAG administration was significantly related to the response and outcome (p = 0.0002). Hematological and nonhematological toxicities were acceptable. In conclusion, the FLAG regimen has significant antileukemic activity and acceptable toxicity especially in secondary AML, both with and without coexisting lymphoid malignancy.

A Branch-and-Bound Algorithm for the Capacitated Vehicle Routing Problem on Directed Graphs

Abstract: We consider the asymmetric capacitated vehicle routing problem CVRP, a particular case of the standard asymmetric vehicle routing problem in which only the vehicle capacity constraints are imposed. CVRP is known to be NP-hard and finds practical applications in distribution and scheduling. We describe two new bounding procedures for CVRP, based on the so-called additive approach. Each procedure computes a sequence of nondecreasing lower bounds, obtained by solving different relaxations of CVRP. Effective implementations of the procedures are also outlined which considerably reduce the computational effort. The two procedures are combined into an overall bounding algorithm. A branch-and-bound exact algorithm is then proposed, whose performance is enhanced by means of reduction procedures, dominance criteria, and feasibility checks. Extensive computational results on both real-world and random test problems are presented, showing that the proposed approach favorably compares with previous algorithms from the literature.