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Biomedical subjects

M Leone

Publications and source records attributed to M Leone.

At least 19 recordsLinked to original sources
PubMed1998

Properties of human hemoglobins with increased polarity in the alpha- or beta-heme pocket. Carbonmonoxy derivatives.

The spectroscopic, conformational, and functional properties of mutant carbonmonoxy hemoglobins in which either the beta-globin Val67(E11) or the alpha-globin Val62(E11) is replaced by threonine have been investigated. The thermal evolution of the Soret absorption band and the stretching frequency of the bound CO were used to probe the stereodynamic properties of the heme pocket. The functional properties were investigated by kinetic measurements. The spectroscopic and functional data were related to the conformational properties through molecular analysis. The effects of this nonpolar-to-polar isosteric mutation are: (i) increase of heme pocket anharmonic motions, (ii) stabilization of the A0 conformer in the IR spectrum, (iii) increased CO dissociation rates. The spectroscopic data indicate that for the carbonmonoxy derivatives, the Val --> Thr mutation has a larger conformational effect on the beta-subunits than on the alpha-subunits. This is at variance with the deoxy derivatives where the conformational modification was larger in the heme pocket of the alpha-subunit (Cupane, A., Leone, M., Militello, V., Friedman, R. K., Koley, A. P., Vasquez, G. P., Brinigar, W. S., Karavitis, M., and Fronticelli, C. (1997) J. Biol. Chem. 272, 26271-26278). These effects are attributed to a different electrostatic interaction between Ogamma of Thr(E11) and the bound CO molecule. Molecular analysis indicates a more favorable interaction of the bound CO with Thr Ogamma in the beta-subunit heme pocket.

Carboxyhemoglobin↗
PubMed1998

5-HT1A receptor hypersensitivity in migraine is suggested by the m-chlorophenylpiperazine test.

Involvement of the cerebral serotoninergic system has been invoked to explain the origin of the pain and the vascular phenomena in migraine. To further investigate the type of cerebral serotonin receptors that may be altered in migraine, the prolactin (PRL) and cortisol responses to m-chlorophenylpiperazine (mCPP), a selective 5-HT1A,-5-HT(2A/C) receptor agonist, were monitored in 12 patients suffering from migraine without aura and in 14 matched healthy controls. Each subject underwent two challenges, one with mCPP (0.5 mg/kg) and the other with placebo (orally) using a double-blind crossover design. Anxiety level was measured by the State Trait Anxiety Inventory. Migraine patients had a greater PRL response to mCPP (p = 0.05) and greater anxiety (p < 0.01) than controls; cortisol response to mCPP did not differ suggesting that 5-HT2C receptors are normal in migraine. Augmented PRL response to mCPP could derive from 5-HT1A receptor hypersensitivity, perhaps as as a consequence of anxiety due to pain expectation. Cerebral 5-HT1A hypersensitivity could also explain the increased occurrence of migraine attacks during anxiety.

Adult↗
PubMed1998

Cost- and time-sparing simplified conformal therapy for prostate cancer: is it feasible?

PURPOSE: It was hypothesized that using a simplified technique of volumes profiles determination (STVPD) based on CT data sets (correlate and projection) would increase the target dose without increasing the bladder and rectal dose obtained by conventional simulation techniques. To test this hypothesis, patients referred for radical radiation treatment for prostate carcinoma were prospectively evaluated by performing treatment planning using standard simulation, with (SSB) and without corner blocks (SSWB), STVPD, and 3D beam's eye view. METHODS AND MATERIALS: Twenty-one patients with prostate carcinoma (stage B: 7; stage C: 14) underwent four treatment planning procedures where the field arrangement was defined by standard simulation (SSB and SSWB), STVPD, and 3D beam's eye view (BEV) with a four field (10 MV photons) box technique. Dose-volume histograms (DVHs) for the planning target volume (PTV), bladder, and rectum (relatives to the four techniques) were generated for all patients and compared; average percentage dose to the bladder and rectum were also calculated. RESULTS: STVPD and 3D BEV treated an increased percentage of PTV at 95% isodose level, in comparison to standard simulation (with and without blocks). No statistically significant differences were found between the two techniques. A significant reduction of irradiated bladder volume was found between 3D BEV and STVPD versus simulation with and without blocks (mean percentage dose: 77.3%, 81.8%, 93.5%, and 92.6% respectively). No marked differences were recorded in rectal irradiation (mean percentage dose: 53.1%, 53.7%, 51.9%, and 50.2% respectively). Time required for treatment planning (excluding CT scan and definitive simulation) was less than 15 minutes for STVPD and more than 120 minutes for 3D BEV. CONCLUSION: Our results confirm the inadequacy of standard simulation. It is possible, with conformal therapy, to increase the dose to the PTV, decreasing the irradiated volume of the bladder. The absence of sparing effect in the rectum is discussed. Using a box technique, STVPD can be used routinely to define the PTV in patients with prostate cancer, reducing the time required for treatment planning, with dosimetric results similar to those of 3D BEV.

Aged↗
PubMed1998

Fourier transform infrared analysis of the interaction of azide with the active site of oxidized and reduced bovine Cu,Zn superoxide dismutase.

Binding of azide to the native and arginine-modified bovine Cu,Zn superoxide dismutase in the oxidized and reduced form and to the copper-free derivative has been investigated by Fourier transform infrared spectroscopy. The antisymmetric stretching band of the azide is shifted to higher energy upon coordination to the copper atom of the oxidized form of the native enzyme. Similar spectral changes occur upon interaction of the anion with the Cu-diethylenetriamine model compound. On the other hand, interaction of azide with the native reduced form of the enzyme results in a band shift toward lower energy with respect to the free anion band. The same shift is observed after reaction of the azide with free lysine or arginine but not when it is reacted with other amino acid residues. The antisymmetric band of the azide is not perturbed by addition of the reduced arginine-modified enzyme; it is likely shifted toward higher energy upon addition of oxidized arginine-modified enzyme while it is again shifted toward lower energy in the presence of the copper-free derivative of the unmodified enzyme. It is concluded that azide does not directly coordinate to the copper in the reduced form of Cu,Zn superoxide dismutase but it remains in the active-site pocket in electrostatic interaction with the guanidinium group of Arg141, which is an invariant residue in this class of enzymes.

Animals↗
PubMed1998

Structural and dynamic properties of the homodimeric hemoglobin from Scapharca inaequivalvis Thr-72-->Ile mutant: molecular dynamics simulation, low temperature visible absorption spectroscopy, and resonance Raman spectroscopy studies.

Molecular dynamics simulations, low temperature visible absorption spectroscopy, and resonance Raman spectroscopy have been performed on a mutant of the Scapharca inaequivalvis homodimeric hemoglobin, where residue threonine 72, at the subunit interface, has been substituted by isoleucine. Molecular dynamics simulation indicates that in the Thr-72-->Ile mutant several residues that have been shown to play a role in ligand binding fluctuate around orientations and distances similar to those observed in the x-ray structure of the CO derivative of the native hemoglobin, although the overall structure remains in the T state. Visible absorption spectroscopy data indicate that in the deoxy form the Soret band is less asymmetric in the mutant than in the native protein, suggesting a more planar heme structure; moreover, these data suggest a similar heme-solvent interaction in both the liganded and unliganded states of the mutant protein, at variance with that observed in the native protein. The "conformation sensitive" band III of the deoxy mutant protein is shifted to lower energy by >100 cm-1 with respect to the native one, about one-half of that observed in the low temperature photoproducts of both proteins, indicating a less polar or more hydrophobic heme environment. Resonance Raman spectroscopy data show a slight shift of the iron-proximal histidine stretching mode of the deoxy mutant toward lower frequency with respect to the native protein, which can be interpreted in terms of either a change in packing of the phenyl ring of Phe-97, as also observed from the simulation, or a loss of water in the heme pocket. In line with this latter interpretation, the number of water molecules that dynamically enters the intersubunit interface, as calculated by the molecular dynamics simulation, is lower in the mutant than in the native protein. The 10-ns photoproduct for the carbonmonoxy mutant derivative has a higher iron-proximal histidine stretching frequency than does the native protein. This suggests a subnanosecond relaxation that is slowed in the mutant, consistent with a stabilization of the R structure. Taken together, the molecular dynamics and the spectroscopic data indicate that the higher oxygen affinity displayed by the Thr-72-->Ile mutant is mainly due to a local perturbation in the dimer interface that propagates to the heme region, perturbing the polarity of the heme environment and propionate interactions. These changes are consistent with a destabilization of the T state and a stabilization of the R state in the mutant relative to the native protein.

Animals↗
PubMed1998

[Nasogastric tube: intratracheal malposition and entrapment in a bronchial suture].

We report the unrecognized accidental intratracheal insertion of a nasogastric tube, following endotracheal intubation in a patient scheduled to undergo right lower lobectomy for carcinoma. After surgery, which had an unremarkable course, the trachea was extubated. However, the gastric tube was entrapped and attempts to withdraw it elicited fits of coughing. A chest X-ray showed the tube malpositioned in the right bronchus. A fibreoptic bronchoscopy did not permit removal of the tube extremity which was embedded in the bronchial suture. Finally an additional thoracotomy was required to withdraw the tube securely. The manifestations of the intratracheal position of a nasogastric tube as well as the preventive and diagnostic measures of such a complication are considered.

Aged↗
PubMed1998

Genetic abnormalities of the protein C system: shared risk factors in young adults with migraine with aura and with ischemic stroke?

Migraine, particularly migraine with aura (MA), may be a risk factor for ischemic stroke (IS). The reasons for this association are unknown. We investigated the presence of genetic abnormalities of the protein C system in 83 MA patients, 31 IS patients, and 124 healthy controls, all aged under 45 years. We found an increased frequency of activated protein C resistance due to Arg506Gln factor V mutation, and of protein S deficiency in both disorders, with figures higher than those reported in the general population and significantly different from those found in controls. These prothrombotic genetic abnormalities may be shared risk factors in IS and MA, and may play a role in increasing the risk of cerebrovascular disease in migraineurs.

Activated Protein C Resistance↗
PubMed1998

Abnormal 24-hour urinary excretory pattern of 6-sulphatoxymelatonin in both phases of cluster headache.

The typical cyclic occurrence of cluster headache suggests the involvement of hypothalamic rhythm regulating centers in the pathogenesis of this primary headache. In previous studies, reduced 24-h plasma melatonin levels during the cluster period, loss of circadian melatonin secretion in remission, as well as permanently reduced excretion of urinary melatonin in both illness phases have been reported, supporting the hypothesis of a hypothalamic derangement. In this study, the 24-h urinary excretion of the main melatonin metabolite, 6-sulphatoxymelatonin, was evaluated in 20 cluster period cluster headache patients. Thirteen were retested 12 months later, in the same period of the year, during remission. Fourteen age- and sex-matched healthy subjects were the controls. As expected, significantly higher levels of 6-sulphatoxymelatonin were present in nocturnal urine than in day-time urine in controls, while in both cluster headache groups urinary levels of this metabolite did not differ between day and night. Nocturnal levels of 6-sulphatoxymelatonin were significantly lower in both cluster headache groups than controls. Day-time levels did not differ significantly between the groups. Altered excretion of urinary 6-sulphatoxymelatonin even during remission indicates that at least some of these anomalies are independent of the pain, and provides further evidence of involvement of the hypothalamic rhythm regulating centers in cluster headache.

Adult↗
PubMed1998

Biofeedback-assisted relaxation training for young adolescents with tension-type headache: a controlled study.

Tension-type headache is common in children and adolescents and is generally treated with medication, but emerging literature suggests that various behavioral treatments may provide efficacious alternatives to medication. Juvenile tension-type headache sufferers were randomly assigned to biofeedback-assisted relaxation continued to improve and were superior to the control condition at a 6- and 12-month follow-up (86% versus 50%). Biofeedback-assisted relaxation appears to be an efficacious and durable treatment for juvenile tension-type headache and merits further exploration.

Adolescent↗
PubMed1997

Modification of alpha-chain or beta-chain heme pocket polarity by Val(E11) --> thr substitution has different effects on the steric, dynamic, and functional properties of human recombinant hemoglobin. Deoxy derivatives.

The dynamic and functional properties of mutant deoxyhemoglobins in which either the beta-globin Val67(E11) or the alpha-globin Val62(E11) is replaced by threonine have been investigated through the thermal evolution of the Soret absorption band in the temperature range 300 to 20 K and through the kinetics of CO rebinding after flash photolysis at room temperature. The conformational properties of the modified alpha chain and beta chain distal heme pockets were also studied through x-ray crystallography and molecular modeling. The data obtained with the various techniques consistently indicate that the polar isosteric mutation in the distal side of the alpha chain heme pocket has a larger effect on the investigated properties than the analogous mutation on the beta chain. We attribute the observed differences to the presence of a water molecule in the distal heme pocket of the modified alpha chains, interacting with the hydroxyl of the threonine side chain. This is indicated by molecular modeling which showed that the water molecule present in the alpha chain distal heme pocket can bridge by H bonding between Thr62(E11) and His58(E7) without introducing any unfavorable steric interactions. Consistent with the dynamic and functional data, the presence of a water molecule in the distal heme pocket of the modified beta chains is not observed by x-ray crystallography.

Carbon Monoxide↗
PubMed1997

A case-control study on alcohol and seizures: study design, protocol, and data collection. The ALCE (Alcohol and Epilepsy) Study Group.

We designed a multicenter case control study to evaluate whether chronic alcoholism and alcohol are risk factors for developing a first generalized tonic-clonic epileptic seizure. Cases were 278 patients (92 women, 186 men), with a first generalized tonic-clonic seizure (either idiopathic or symptomatic), matched to 556 controls for center, sex, age, and weekday of the seizure. Information on risk factors was obtained through a questionnaire. This paper focuses on the study design (selection of cases and choice of controls), the validity of the instruments for data collection, and the strategies of study conduction (interviews, use of proxy respondents). Inter-rater agreement was excellent for drinking status, patterns of drinking, and broad indicators of consumption (yes/no). Agreement was variable for the number of servings/week, but was excellent (r = 0.91) for a summary of daily alcohol intake.

Adult↗
PubMed1997

Hepatitis C virus infection among institutionalised psychiatric patients: a regression analysis of indicators of risk.

BACKGROUND/AIMS: Institutionalised psychiatric patients are at increased risk of developing chronic infection with hepatitis B virus (HBV). However, little information is available on transmission and epidemiology of hepatitis C virus (HCV) in this setting. The aim of this study was to identify potential risk factors of acquiring HCV infection in two large psychiatric institutions in northern Italy. METHODS: We designed a case-control study using randomly selected controls from the same study database, consisting of a total of 1180 patients, in order to satisfy the principle that both cases and controls should be representative of the same base experience. A multiple regression logistic analysis was used to identify features that could predict exposure to HCV as evidenced by the presence of circulating anti-HCV antibodies. RESULTS: Anti-HCV was detected in 79 patients (6.7%). The prevalence of viraemia and the distribution of genotypes were very similar to those found in subjects with chronic HCV infection drawn from the same geographical area. Multivariate analysis indicated that a diagnosis of psychosis and a history of trauma were statistically significant independent risk factors associated with a positive anti-HCV result (OR 2.615, 1.273-5.373 95% CI and OR 2.096, 1.133-3.877 95% CI, respectively). CONCLUSIONS: The findings of this large epidemiological study show for the first time that prolonged residence in psychiatric institutions does not entail per se a significant risk of acquiring HCV infection. Since transmission of HCV in this setting appears to occur predominantly via classical parenteral routes, simple prophylactic measures appear to be adequate to prevent infection.

Adult↗
PubMed1997

The m-chlorophenylpiperazine test in cluster headache: a study on central serotoninergic activity.

The central serotoninergic agonist m-chlorophenylpiperazine (m-CPP) stimulates several 5HT receptor subtypes. It induces the release of both cortisol and prolactin (PRL). In this study we investigated central serotoninergic responsiveness in cluster headache by monitoring cortisol and PRL responses to m-CPP administration. Twenty-three patients with episodic cluster headache and 17 sex-matched and age-matched healthy subjects were studied. The cluster headache patients were tested during a cluster period, and none were receiving prophylaxis. A single oral dose of m-CPP, 0.5 mg/kg, was given at time 0. Blood samples were drawn at -30, 0, 30, 60, 90, 120, 150 and 180 min. PRL and cortisol levels were assayed in the samples. PRL and cortisol delta maxima (delta maximum = maximum response - baseline level at time 0/baseline level at time 0) were evaluated in each patient and mean values compared. Serum levels of m-CPP were detected by HPLC and correlated to hormonal responses. Reduced cortisol (p < 0.02) and increased PRL (p < 0.05) delta maxima were observed in cluster headache patients. Increased basal cortisol plasma levels (p < 0.05) and reduced basal PRL plasma levels (p = 0.06) also characterized cluster headache patients. This is the first study evaluating central serotoninergic responsiveness to m-CPP in cluster headache and these data suggest impaired central serotoninergic function in this pathology.

Case-Control Studies↗
PubMed1997

Coexistence of migraine and cluster headache: report of 10 cases and possible pathogenetic implications.

We report on 10 patients suffering from two types of primary headache, migraine and cluster, diagnosed according to IHS criteria, and selected from headache patients attending two Italian headache centers. We briefly review the literature on coexisting migraine and cluster headache, considering the time relationships between these two headaches. The present series seems not to confirm the hypothesis that migraine transforms into cluster headache since both headaches persist together in the patients. The series is of clinical interest particularly with regard to diagnosis and to treatment strategies. Furthermore, while migraine and cluster headache comorbidity must be confirmed by population-based epidemiological studies, the possibility arises that the two conditions may be linked pathophysiologically: common genetic factors or functional alterations in the same central neurological circuits may play a role in the pathogenesis of both disorders.

Adult↗
PubMed1997

Transdermal clonidine in the prophylaxis of episodic cluster headache: an open study.

Transdermal clonidine has recently been reported to be efficacious in the prophylaxis of cluster headache. A 2-week course of transdermal clonidine (5 mg the first week, 7.5 mg the second week) preceded by a 5-day run-in period, was administered to 16 patients with episodic cluster headache in an active cluster period. In 5 patients, the painful attacks disappeared after the seventh day of treatment. For the group as a whole, no significant variations in headache frequency, pain intensity, or attack duration were observed between the run-in period and the first and second weeks of treatment (ANOVA). Further studies are necessary to clarify the effectiveness of transdermal clonidine in the prophylaxis of episodic cluster headache.

Administration, Cutaneous↗
PubMed1997

Alcohol use is a risk factor for a first generalized tonic-clonic seizure. The ALC.E. (Alcohol and Epilepsy) Study Group.

We performed a multicenter case-control study to estimate whether chronic alcoholism and alcohol consumption are risk factors for developing a first generalized tonic-clonic seizure (GTCS). We studied 237 first-seizure patients (158 men, 79 women) matched to 474 hospital controls for center, sex, age (+/-5 years), and weekday of the seizure. The risk of first GTCS in alcoholics was greater than in non-alcoholics for men (odds ratio, 6.8; 95% confidence limits, 3.6-13.0) and women (6.8, 1.6-32.6). The odds ratio (both sexes) was 1.2 (0.8-1.8) for an average daily intake of absolute alcohol of 1 to 25 g/day and rose with the amount of alcohol consumed daily: 1.3 (0.8-2.1) for 26 to 50 g/day, 3.0 (1.7-5.4) for 51 to 100 g/day, 7.9 (2.9-21.9) for 101 to 200 g/day, and 16.6 (1.9-373.4) for >200 g/day. Our study provides evidence of a powerful association between alcohol use, alcoholism, and the first GTCS.

Alcohol Drinking↗
PubMed1997

[Computerization experience in a day hospital of integrated radiochemotherapy].

INTRODUCTION: We report on a cost-effective easy-access software developed for the functional integration of the clinical records and history of oncologic patients with the management of the Day Hospital of the Radiotherapy Department of the University Hospital A. Gemelli, in Rome. MATERIAL AND METHODS: The software was designed to archive the clinical records and history of oncologic patients and the relative chemotherapy, to manage the examination scheduling, to draw up nursing files with the planned therapy and to make statistical analyses of the department activity. Five forms are available: the patient form, recording patient data; the admission form, recording the type of therapy (e.g., chemotherapy, tests, medical examinations, etc.), the relative cost and chemotherapy protocol, detailing for instance the type of drug; the nursing file, detailing chemotherapy schedule and the dilution of each drug; the menu, to select and retrieve any record. The minimum configuration requires a 386 Intel CPU, 4 Mb RAM and 4 Mb free on the hard disk. The software is the File Maker Pro 2.1 for Windows which can interact with Apple Macintosh computers. RESULTS: Since October, 1995, we have saved the clinical records of 272 oncologic outpatients (2415 entries in all), with a mean of 201/month. This computer system permitted us to save and retrieve data for both clinical and didactic purposes and to plan our activity. CONCLUSIONS: One year after it was implemented and used in clinical practice, the system is a cost-effective and user-friendly tool for the management of the Radiochemotherapy Day Hospital of our Radiotherapy Department.

Combined Modality Therapy↗