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Biomedical subjects

M Leone

Publications and source records attributed to M Leone.

At least 127 records · Page 7Linked to original sources
PubMed1995

Low-temperature optical spectroscopy of cobalt in Cu,Co superoxide dismutase: a structural dynamics study of the solvent-unaccessible metal site.

The temperature dependence (300 to 10 K) of the electronic absorption spectra of the cobalt chromophore in bovine superoxide dismutase (SOD) having the native Zn(II) ion selectivity replaced by Co(II) has been investigated in four different derivatives: Cu(II),Co(II) SOD, N3(-)-Cu(II), Co(II) SOD, Cu(I),Co(II) SOD, and E,Co(II) SOD in which the copper ion has been selectively removed. In the Cu(II),Co(II) SOD, the cobalt spectrum is characterized at room temperature by three bands centered at 18,472, 17,670, and 16,793 cm-1; the low-frequency band is split, at low temperatures, into two components, indicating a lower symmetry contribution to a predominantly tetrahedral crystal field. Addition of N3- to the Cu(II),Co(II) SOD introduces slight changes in all the Co(II) visible bands, indicating the occurrence of minor perturbations of the structural cobalt site upon anion binding to the catalytic copper site. Analysis of the spectra in the Cu(I),Co(II) and E,Co(II) enzymes indicates that the His61 imidazolate bridge is released from the copper upon reduction. This is also confirmed by the analysis of the zeroth, first, and second moments of the various bands in the derivatives. The cobalt site is characterized by a harmonic dynamics, at variance with what observed in the solvent accessible copper site [Cupane, A., Leone, M., Militello, V., Stroppolo, M. E., Polticelli, F., & Desideri, A. (1994) Biochemistry 33, 15103-15109]. The degree of local microheterogeneity at the cobalt site is smaller than that observed for the copper site and increases in the order N3(-)-Cu(II),Co(II) approximately Cu(II),Co(II) < Cu(I),Co(II) < E,Co(II) indicating a different local packing and the presence of different constraints on the cobalt site in the four derivatives. The different dynamic behavior with respect to the catalytic, solvent-accessible, copper site is discussed.

Animals↗
PubMed1995

Dynamic properties of some beta-chain mutant hemoglobins.

The thermal behavior of the Soret band relative to the carbonmonoxy derivatives of some beta-chain mutant hemoglobins is studied in the temperature range 300-10 K and compared to that of wild-type carbonmonoxy hemoglobin. The band profile at various temperatures is modeled as a Voigt function that accounts for homogeneous broadening and for the coupling with high- and low-frequency vibrational modes, while inhomogeneous broadening is taken into account with a gaussian distribution of purely electronic transition frequencies. The various contributions to the over-all bandwidth are singled out with this analysis and their temperature dependence, in turn, gives information on structural and dynamic properties of the system studied. In the wild-type and mutant hemoglobins, the values of homogeneous bandwidth and of the coupling constants to high-frequency vibrational modes are not modified with respect to natural human hemoglobin, thus indicating that the local electronic and vibrational properties of the heme-CO complex are not altered by the recombinant procedures. On the contrary, differences in the protein dynamic behavior are observed. The most relevant are those relative to the "polar isosteric" beta Val-67(E11)-->Thr substitution, localized in the heme pocket, which results in decreased coupling with low-frequency modes and increased anharmonic motions. Mutations involving residue beta Lys-144(Hc1) at the C-terminal and residue beta Cys-112(G14) at the alpha 1 beta 1 interface have a smaller effect consisting in an increased coupling with low-frequency modes. Mutations at the beta-N-terminal and at the alpha 1 beta 2 interface have no effect on the dynamic properties of the same heme pocket.

Base Sequence↗
PubMed1995

Low temperature optical absorption spectroscopy: an approach to the study of stereodynamic properties of hemeproteins.

In this short review we show how suitable analysis of the temperature dependence of the optical absorption spectra of metalloproteins can give insight into their stereodynamic properties in the region of the chromophore. To this end, the theory of coupling between an intense allowed electronic transition of a chromophore and Franck-Condon active vibrations of the nearby atoms is applied to the Soret band of hemeproteins to obtain an analytical expression suitable for fitting the spectral profile at various temperatures. The reported approach enables one to separate the various contributions to the overall bandwidth together with the parameters that characterize the vibrational coupling. The thermal behavior of these quantities gives information on the dynamic properties of the active site and on their dependence upon protein structure and ligation state. The Soret band of hemeproteins appears to be coupled to high frequency vibrational modes of the heme group (as already shown by resonance Raman spectroscopy) and to a "bath" of low frequency modes most likely deriving from the bulk of the protein. For the deoxy derivatives inhomogeneous broadening arising from conformational heterogeneity appears to contribute substantially to the linewidth. The data indicate the onset, at temperatures near 180 K, of large scale anharmonic motions that can be attributed to jumping among different conformational substates of the protein.

Animals↗
PubMed1995

A review of the treatment of primary headaches. Part I: Migraine.

Finding the best treatment for a patient's migraine is often a problem in clinical practice since the condition is very common, often debilitating and may prove refractory to therapy. Over recent years, more effective migraine treatments have been found and validated, and the traditional remedies have undergone controlled testing. This article reviews the various therapies available for both the acute treatment and prevention of migraine. Treatments often effective against migraine attacks are: aspirin, analgesics, non steroid anti-inflammatory drugs (NSAIDs), ergot derivatives and sumatriptan. Five main classes of prophylactic drug are currently used: beta-blockers, calcium antagonists, serotonin modulators, NSAIDs and ergot compounds. Biofeedback, one of the most efficacious non-pharmacological preventive treatments of migraine, is also discussed. The variables influencing the choice of acute and preventive treatments, including contraindications and drug availability, are also described in order to provide a practical and up-to-date guide to migraine therapy.

Biofeedback, Psychology↗
PubMed1995

The incidental finding of abnormal cervical histology in postmenopausal patients.

A report is supplied on 216 samples of cervical tissue incidentally found in 684 endometrial specimens collected during hysteroscopic examination of postmenopausal women with uterine bleeding and a recent negative Pap smear. We found 43 (19.9%) specimens including cervical tissue with some histologic sign of pathology. Twenty-five (11.6%) had histologic features suggestive for human papillomavirus (HPV) infection, while 18 (8.3%) had cervical intraepithelial neoplasia (CIN). Of the 18 CIN cases, 9 were CIN I, 6 CIN II and 3 CIN III. Altogether, the prevalence of dysplasia in postmenopausal women with recently referred normal cervical cytology was impressive. A significant number of dysplastic lesions (14 out of 18, 77.7%) did not present any histologic sign of HPV. Also, none of the histologic diagnoses of sub-clinical HPV infection was confirmed by the in situ hybridization. Considering the significant prevalence of high grade lesions (9 CIN II and III, 4.2% of the analysed samples) found in this randomly selected patient population, our data strongly suggest the need for a regular follow-up of the transformation zone in all postmenopausal women. Although in women of postmenopausal age some low grade lesions seem to have only a reactive-reparative significance, a more accurate screening procedure, taking into account the peculiar modifications of the menopausal uterine cervix, is advisable.

Adult↗
PubMed1995

Twenty-four-hour melatonin and cortisol plasma levels in relation to timing of cluster headache.

The cyclic recurrence of cluster periods and the regular timing of headache occurrence in cluster headache (CH) induced us to study the circadian secretion of melatonin and cortisol in 12 patients with episodic CH, during a cluster period, and compare them with 7 age- and sex-matched healthy controls. Blood was sampled every 2 h for 24 h. All subjects were confined to a dark room from 22.00 to 08.00. Plasma melatonin levels were significantly reduced in CH patients (repeated measures ANOVA p < 0.03; mesor p < 0.02), and the cortisol mesor was significantly increased (p < 0.03). Amplitudes and acrophases did not differ between the groups. Individual cosinor analysis showed that 4/12 (33.3%) CH patients had no significant melatonin rhythm, and that 5/11 (45.5%) had no cortisol rhythm. Group analysis of cosinor revealed significantly rhythmicity of melatonin and cortisol secretion in both groups. In controls, the timing of melatonin and cortisol acrophase significantly correlated with each other, indicating that the biorhythm controllers for the secretion of these hormones were synchronized. Such correlation was not found in the CH patients; mesor, amplitude and acrophase of melatonin and cortisol did not correlate with duration of illness, duration of headache in course, or time since last headache attack.

Adult↗
PubMed1995

Possible identification of cervicogenic headache among patients with migraine: an analysis of 374 headaches.

According to Sjaastad, the pain in cervicogenic headache, a form not recognized by the IHS, is long lasting and always side-locked unilateral. The frequency of side-locked unilateral pain (defined here as no change in side from onset) and other characteristics of cervicogenic headache were investigated in 300 outpatients using information collected on standard forms in structured interviews. Three hundred seventy-four headaches diagnosed according to IHS criteria were identified. Three hundred forty-eight of these headaches were long-lasting (duration of more than 4 hours); migraine (65%) followed by tension-type headache (25%) were the commonest forms. Side-locked unilaterality was present in 29% (101 of 348), and occurred most frequently in migrainous disorders not fulfilling the criteria (25 of 56, 44.6%). This group differed significantly from the other migraine conditions for longer pain duration (P < 0.02) and less frequent nausea, vomiting, photophobia, phonophobia (P < 0.0001), and aggravation by physical activity (P < 0.02). With these characteristics, this group resembled cervicogenic headache. However, in none of these patients was pain triggered by head or neck movements, and the frequency of head or neck trauma did not differ from other headaches. A more precise definition of clinical criteria for cervicogenic headache vs migraine is, therefore, required.

Adolescent↗
PubMed1995

Hereditary ataxias and paraplegias in Valle d'Aosta, Italy: a study of prevalence and disability.

INTRODUCTION: a study was conducted in the Valle d'Aosta Region, Italy, (115270 inhabitants) to determine the prevalence of hereditary ataxias (HA) and hereditary spastic paraplegias (HSP), and the degree of disability they cause. METHODS: we identified all patients with suspected HA or HSP referred from 1981 to 1991 to in- and out-patient departments, EEG, EMG, and CT-scan services, and centres for the handicapped. Harding's criteria were followed for diagnosis and classification. RESULTS: at the prevalence day, 17 patients were alive, with a prevalence ratio of 14.8/100,000 population. There were 2 cases of Friedreich's ataxia (FA), 1 of early onset cerebellar ataxia with retained tendon reflexes (EOCA), 1 of autosomal dominant cerebellar ataxia (ADCA), 8 of sporadic idiopathic late onset cerebellar ataxias, and 5 of HSP. CONCLUSIONS: epidemiological studies on HA and HSP show highly variable prevalence ratios, which could be due in part to the inclusion of sporadic cases. FA, EOCA and ADCA have similar prevalence ratios in most studies.

Adolescent↗
PubMed1994

Low-temperature optical spectroscopy of native and azide-reacted bovine Cu,Zn superoxide dismutase. A structural dynamics study.

The optical absorption spectra of native and N(3-)-reacted Cu,Zn superoxide dismutase (SOD) has been studied in the temperature range 300-10 K. The broad d-d bands observed in the room temperature spectrum, centered at 14,700 cm-1 (native enzyme) and at 15,550 cm-1 (N(3-)-reacted enzyme), are clearly split at low temperature into two bands each, centered at 12,835 and 14,844 cm-1 and at 14,418 and 16,300 cm-1, respectively. The thermal behavior of the 23,720 cm-1 band present in the spectrum of the native enzyme indicates that this band belongs to the His61-->Cu(II) ligand to metal charge transfer transition. Analysis of the zeroth, first, and second moments of the various bands as a function of temperature allowed us to obtain useful information on the stereodynamic properties of the metal site in SOD. In particular for the native protein, it was possible to infer a variation in the metal ligand relative position that occurs as the temperature is lowered and that likely involves all of the ligands except His61. On the other hand, the site is stabilized upon N3- binding, and in this case a variation in the metal ligand position is observed only at the level of the bound anion. The possible relation of these properties to the catalytic mechanism of the enzyme is discussed.

Animals↗
PubMed1994

Thermal broadening of the Soret band in heme complexes and in heme-proteins: role of iron dynamics.

We report the thermal broadening of the Soret band in heme-CO, heme-OH and protoporphyrin IX in the temperature range 300-20 K. For protoporphyrin IX the temperature dependent Gaussian line broadening follows the behavior predicted by the harmonic approximation in the entire temperature range investigated. In contrast, for heme-CO and heme-OH the harmonic behavior is obeyed only up to about 180 K and an anomalous line broadening increase is observed at higher temperatures. This effect is attributed to the onset of anharmonic motions of the iron atom with respect to the porphyrin plane. Comparison with previously reported analogous data for heme proteins enables us to suggest that the onset of substrate interconversions in these latter systems can be reflected in motions of the iron atom with respect to the porphyrin plane.

Animals↗
PubMed1994

Stereodynamic properties of the cooperative homodimeric Scapharca inaequivalvis hemoglobin studied through optical absorption spectroscopy and ligand rebinding kinetics.

The study of the thermal evolution of the Soret band in heme proteins has proved to be a useful tool to understand their stereodynamic properties; moreover, it enables one to relate protein matrix fluctuations and functional behavior when carried out in combination with kinetic experiments on carbon monoxide rebinding after flash photolysis. In this work, we report the thermal evolution of the Soret band of deoxy, carbonmonoxy, and nitric oxide derivatives of the cooperative homodimeric Scapharca inaequivalvis hemoglobin in the temperature range 10-300 K and the carbon monoxide rebinding kinetics after flash photolysis in the temperature range 60-200 K. The two sets of results indicate that Scapharca hemoglobin has a very rigid protein structure compared with other hemeproteins. This feature is brought out i) by the absence of nonharmonic contributions to the soft modes coupled to the Soret band in the liganded derivatives, and ii) by the almost "in plane" position of the iron atom in the photoproduct obtained approximately 10(-8) s after dissociating the bound carbon monoxide molecule at 15 K.

Animals↗
PubMed1994

Leukocyte subsets and cortisol serum levels in patients with migraine without aura and chronic tension-type headache.

Leukocyte subsets, serum cortisol and immunoglobulin production were investigated in a group of 12 migraine without aura patients, 12 chronic tension-type headache patients and compared with findings in 12 healthy controls. Chronic tension-type headache patients had statistically significant increased levels of B-lymphocytes (CD19+ cells) (p < 0.05), while migraine sufferers had a similarly significant decrease in CD8+ T-lymphocytes (p < 0.05). Migraine patients also had an increased percentage of B-lymphocytes although this failed to reach statistical significance. Immunoglobulin production and cortisol serum levels did not differ in the two headache groups. We conclude that the observed abnormalities in tension-type headache and migraine are unlikely to be a consequence of pain or of hypothalamic-pituitary-adrenal axis dysfunction.

Adult↗
PubMed1994

Assessment of International Headache Society diagnostic criteria: a reliability study.

In 1988 the International Headache Society (IHS) introduced new diagnostic criteria for headaches and craniofacial pain. Since headaches can be diagnosed solely on the basis of information provided by the patient, it is essential that the criteria are reproducible and consistent. Two neurologists evaluated the clinical records of 100 consecutive outpatients and transferred the data on headache and associated phenomena to a form designed to reflect the IHS criteria. Interobserver concordance (kappa statistics) in the application of the diagnostic criteria of primary headaches was: (i) "perfect" to "substantial" for the first IHS digit, being kappa = 1.0 for cluster headache and paroxysmal hemicrania; kappa = 0.88 for migraine; kappa = 0.75 for tension-type headache; (ii) "almost perfect" to "substantial" for the second digit (kappa = 0.94 for cluster headache; kappa = 0.90 for migraine with aura; kappa = 0.81 for episodic tension-type headache; kappa = 0.78 for migraine without aura; kappa = 0.71 for chronic tension-type headache; kappa = 0.66 for cluster headache-like disorder not fulfilling the criteria; (iii) "moderate" for migrainous disorder (kappa = 0.48) and headache of the tension-type (kappa = 0.43) not fulfilling the criteria. These results show that the IHS diagnostic criteria are satisfactorily applicable to high quality medical records abstracted by experienced neurologists.

Adolescent↗
PubMed1994

The insulin tolerance test and ovine corticotrophin-releasing-hormone test in episodic cluster headache. II: Comparison with low back pain patients.

Hypothalamic involvement has been invoked to explain the periodicity of the cluster periods and rhythmicity of the pain attacks in cluster headache. To explore this hypothesis the ovine corticotrophin-releasing headaches sufferers during both cluster period and remission. A group of low back pain patients and healthy subjects comprised the control populations. For the o-CRH test, 7 healthy subjects, 7 low back pain patients, 6 cluster headache patients in remission, and 12 in cluster period were studied. Five healthy subjects, 7 low back pain patients, 6 cluster headache patients in remission, and 9 cluster period were administered the insulin tolerance test. Significantly increased basal cortisol levels were found in cluster headache patients in both illness phases (p < 0.0001), but not in low back pain patients. Significantly reduced cortisol response to the o-CRH test was observed in cluster headache patients in both phases compared to healthy controls (p < 0.02). A blunted ACTH and cortisol response (p < 0.0001 and p < 0.003 respectively) to the insulin tolerance test was present in cluster headache patients in both phases of the illness compared to healthy subjects and low back pain patients. On the contrary, the ACTH surge after insulin induced hypoglycemia was significantly increased in the low back pain patient group (p = 0.02). These results suggest that the altered hypothalamic-pituitary-adrenal axis responsiveness in cluster headache patients is not a consequence of the pain, and point to a central, probably hypothalamic derangement in this pathology.

Adrenocorticotropic Hormone↗
PubMed1994

Internal ophthalmoplegia associated with migraine attacks.

The case of a young woman presenting with repeated headache episodes associated with right eye midriasis is described. CT scan, MR of the brain and selective cerebral angiography were unremarkable. Tyramine eyedrop response suggested parasympathetic hypofunction on the affected side. The diagnosis of ophthalmoplegic migraine is proposed.

Adult↗
PubMed1994

Side-locked unilaterality and pain localization in long-lasting headaches: migraine, tension-type headache, and cervicogenic headache.

Side-locked unilaterality and specific localization of pain are not as well-defined clinical characteristics in long-lasting headaches (duration more than 4 hours) as they are in short-lasting forms. We examined side-locked unilaterality and pain distribution at onset and at peak headache in 74 patients with different forms of long-lasting headache: migraine and tension-type headache (IHS) and cervicogenic headache (according to Sjaastad et al). Side-locked unilaterality of pain was found in all forms, but to differing extents - 20.8% in migraine, 12.5% in tension-type headache, while it was a mandatory criterion for cervicogenic headache. The pain tended to localize anteriorly, particularly at onset, in migraine; was more diffuse in tension-type headache; and always began in the occipitonuchal region in cervicogenic headache. Our results may contribute to a better clinical definition of long-lasting headaches.

Adult↗