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G D'Alessandro

Publications and source records attributed to G D'Alessandro.

At least 19 recordsLinked to original sources
PubMed2004

Average patterns and coherent phenomena in wide aperture lasers.

Using a realistic model of wide aperture, weakly astigmatic lasers we develop a framework to analyze experimental average intensity patterns. We use the model to explain the appearance of patterns in terms of the modes of the cavity and to show that the breaking of the symmetry of the average intensity patterns is caused by overlaps in the frequency spectra of nonvanishing of modes with different parity. This result can be used even in systems with very fast dynamics to detect experimentally overlaps of frequency spectra of modes.

Journal Article↗
PubMed2002

Epidemiology of primary intracranial tumours in NW Italy, a population based study: stable incidence in the last two decades.

Data about the epidemiology of primary intracranial tumours (PIT) are still heterogeneous depending on different methodological approach in collecting data. In Valle d' Aosta, north west side of Italy, we have carried out a prospective consecutive population based study to calculate the incidence of PIT in the last decade (1992-1999) and to compare these rates with the previous period (1986-1991), data reported in a previous paper. The mean annual PIT incidence rate (ri) per 100,000 inhabitants was 25.48. The mean annual incidence rates in the two period of comparison were adjusted to the 1991 Italian population by the direct method. The standardised ratio was 26.43 in the previous period and 23.24 in the second decade. There is no statistically significant difference. The mean annual PIT incidence rates by tumour types were meningiomas 13.27/100,000 (men 9.77; women 16.7), neuroepithelial group 9.3 (men 10.62; women 8.1), adenomas 1.26, neurinomas 0.7. Mean annual incidence rates by tumour class were also stable. The stable incidence rate in the two periods and the similar incidence in England (21.04/100,000 person year), strengthen the evidence for a stable incidence rate of PIT in the last decade. These three papers used similar methodology. The homogeneous methodology allows comparison and further evaluation.

Adenoma↗
PubMed2000

Temporal trends of stroke in Valle d'Aosta, Italy. Incidence and 30-day fatality rates.

The objective of this study was to evaluate temporal changes of stroke in an Italian community by comparing the present incidence rates with those reported in the same area for 1989. The two studies were conducted by the same research group and met almost all the criteria proposed for an "ideal" stroke incidence study. The annual incidence rate per 1000 inhabitants increased (p < 0.01) by 29%, from 2.23 (95% CL, 1.96-2.50) in 1989 to 2.89 (95% CL, 2.58-3.20) in 1997. No statistically significant change was found when these rates were adjusted to the 1991 Italian population. The overall incidence rate was 2.40 (95% CL, 2.14-2.66) in 1989 and 2.65 (95% CL, 2.39-2.91) in 1997. The thirty-day case fatality rate declined dramatically (p < 0.001) from 31% (95% CL, 26-36) to 20% (95% CL, 16-24) between 1989 and 1997. Ageing of the population and better identification of cases could explain the high incidence rate, whereas the decrease of fatality rate may be due to a general improvement in acute care and inclusion of milder cases.

Adolescent↗
PubMed2000

Thyrotoxic periodic paralysis in a Caucasian man in treatment for Graves' disease.

Thyrotoxic periodic paralysis (TPP) is the main secondary form of hypokalemic periodic paralysis and is mostly associated with Graves' disease. Initially diagnosed in Asian countries, TPP has been sporadically reported in different populations of the Western World. Increased Na+/K(+)-ATPase activity seems to be responsible for the marked hypokalemia observed during the transient paralysis attacks. We report on a 35-year-old Italian man without history of hypokalemic periodic paralysis and hyperthyroidism, in treatment for Graves' disease, who suffered episodes of flaccid paralysis even with normal thyroid hormone levels. An insulin-glucose provocation test confirmed our diagnosis. Oral and parenteral potassium reverse the symptoms. Monitoring of thyroid function is also important to prevent further attacks.

Adult↗
PubMed1999

Prevention of cardioembolic stroke: use of oral anticoagulants in patients with atrial fibrillation.

With the aim of quantifying the use of oral anticoagulant (OA) therapy in clinical practice, we surveyed 150 consecutive patients admitted with a diagnosis of atrial fibrillation (AF). Each patient was administered a questionnaire relating to the classic vascular risk factors and to the antithrombotic treatment received at home. The diagnosis of AF was formulated at the time of admission in 45 cases. Of the 105 cases with a previous diagnosis, OA therapy was relatively or absolutely contraindicated in 21 patients (20%), whereas the other 84 (80%) were ideal candidates for the treatment. Of these, 20 (24%) were actually receiving OA, 16 (19%) were on platelet anti-aggregants (PA), and 48 (57%) were receiving no antithrombotic treatment at all. Even lower percentages of OA use were found in the patients with a previous (20%) or recent (16%) history of cerebral ischemia. Upon discharge, of the 115 patients without contraindications to OA (84 with previously known and 31 with newly diagnosed AF), 50% were receiving OA and 20% PA. The results of this survey show that OA therapy is little used in the Valle d'Aosta Region for the prevention of ischemic stroke in AF patients at high risk for cerebral ischemia. The lack of knowledge among the general population, the difficulty of initiating the therapy in patients such as ours with severe comorbidities, and the absence of disorganization of centers for OA monitoring may be the main reasons underlying this low level of use. Population screening or a sensitization campaign could increase the identification of subjects at risk, whereas better organization of coagulation monitoring centers could encourage OA use in subjects at high risk for cerebral ischemia.

Administration, Oral↗
PubMed1998

[Epidemiology and chronorhythmicity of recurrences of attempted suicide].

The authors examine cases of attempted suicide admitted to Hospital of Foggia from 1 January 1990 to 31 December 1996. They describe characteristics of repeaters. A total of 611 episodes of attempted suicide regarding 552 different subjects were observed during the study period. Women attempted suicide more than men. No significant difference was observed for age and repeaters between men and women; while women outnumbered men in cases of single episode. Attempted suicide showed a circadian rhythm for both in first-event cases and repeaters; against, circaseptan and circannual periodicity were not present in both groups. Women had a greatest risk of an other repetition after a free period from events, in fact the time between the first and the latest episode was greater for women than for men. Commonly, the repeaters attempted at suicide again making use of the same method used for the first episode.

Adult↗
PubMed1996

Evaluation of a new rapid quantitative D-dimer assay in patients with clinically suspected deep vein thrombosis.

The sensitivity and specificity for deep vein thrombosis (DVT) of a new rapid, quantitative and precise (total imprecision < 10%) D-dimer assay suitable for individual measurements (VIDAS D-DIMER, bio-Mérieux, France) were evaluated in a consecutive series of 103 in- and out-patients submitted to serial compression ultrasonography (C-US) for the clinical suspicion of DVT (n = 66) or of DVT recurrence (n = 37) and symptoms lasting from 1 to 15 days. DVT was found in 22 patients at baseline testing and no patient with an initially negative C-US developed vein incompressibility at follow up. The time elapsed from the onset of symptoms was negatively associated with D-dimer levels both in patients with and in those without DVT. In the entire series of patients, the sensitivity of a positive D-dimer test ( > or = 1.0 microgram/ml) for the presence of DVT was 96% (21/22 patients, 95% confidence interval 75-100%) with a specificity of 75% (64-84%), a negative predictive value of 98% (90-100%), a positive predictive value of 51% (35-67%), and an overall accuracy of 80% (70-87%). A normal D-dimer value (0.22 microgram/ml) was observed in one patient with DVT and symptoms lasting from 15 days. The approach of withholding C-US testing in patients with symptoms lasting from less than 11 days and D-dimer levels below the cut-off value was compared to serial C-US testing alone in a cost-effectiveness analysis subdividing the 66 patients with a first episode according to their clinical pretest probability of DVT. Thrombosis was detected in 6.7% of the patients in the low probability group (n = 15), 16.7% of the patients in the moderate probability group (n = 24), 51.9% of the patients in the high probability group (n = 27) and 8.1% of patients with suspected DVT recurrence. Calculated cost-savings for each DVT diagnosed ranged from 5% in the high pretest probability group to 55% in the low pretest probability group and to 77% in patients with suspected DVT recurrence. The safety of avoiding C-US testing in symptomatic patients with a negative D-dimer test should be evaluated in clinical management studies.

Adult↗
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↗
PubMed1995

Epidemiology of primary intracranial tumors in the Valle d'Aosta (Italy) during the 6-year period 1986-1991.

A total of 285 new cases of primary intracranial tumors (PIT: 178 cases, 62%) and secondary forms (107 cases, 38%) were detected by CT scan and MRI during a population-based study of the incidence rates of these neoplasms in the Aosta Valley (N.W. Italy: 114,325 residents in 1988) during the period 1986-1991. The PIT are discussed in this paper. Histological confirmation was obtained in 60%. Age- and sex-adjusted mean annual incidence rate for all PIT was 28.3/100,000 (men 21.7; women 28.1). The incidence rates by types were 9.7 for meningiomas (men 5.3; women 13.9), 9.1 for tumors of the neuroepithelial group (men 10; women 8.1), 3.7 for adenomas (men 2.6; women 4.6), and 1.9 for neurinomas (men 2.9; women 0.9). Incidence rate increased with age. Meningiomas comprised 37% of the PIT, followed by tumors of the neuroepithelial group (35%), adenomas (14%, neurinomas (7.3%) and malignant lymphomas (2.3%). The remaining subtypes were 4.6%. Our data showed a clearly higher incidence rate than in previous population-based surveys. The differences were most marked in the meningioma group. The extensive use of CT scan and the more intensive case-finding could explain the differences.

Adenoma↗
PubMed1992

Peripheral neuropathy caused by antiepileptic drugs. Neurophysiological study of the A delta and C fibers.

The risk that antiepileptic drugs may cause damage to the peripheral nervous system led us to investigate 12 patients on carbamazepine and 12 patients on phenobarbital with the thermal threshold test. The heat and cold thresholds were measured at the ankle and wrist and, compared with those in 30 healthy subjects, they proved to be significantly higher. When the two groups of epileptics were compared separately with the controls, their thresholds were always higher. These findings are consistent with a toxic effect of both drugs on fine peripheral nerve fibers.

Adolescent↗
PubMed1992

Clinical and neuroradiological findings in a case of pure word deafness.

Pure Word Deafness is a clinical syndrome included among the aphasias and is marked by complete deafness of sudden onset with conserved ability to understand and read the written word and with no speech disorders. We report the case of 61 year old man in whom pure word deafness developed after two episodes of acute cerebral ischemia in quick succession. Neuroimaging procedures, that is: computed tomography scan, single photon emission computed tomography and magnetic resonance imaging, revealed the presence of two ischemic lesions in the temporal cortex bilaterally. Neurophysiological investigations (electroencephalogram, brainstem auditory evoked potentials and stapedial reflex) were also studied. We discuss the outcome of all these investigations in the light of the relevant published work.

Brain↗
PubMed1992

Incidence and prognosis of stroke in the Valle d'Aosta, Italy. First-year results of a community-based study.

BACKGROUND AND PURPOSE: We sought to determine the incidence rate, risk factors, and prognosis of stroke in Valle d'Aosta, Italy, to provide information for planning regional health-care facilities. METHODS: We undertook a prospective study of all new cases of stroke in the geographically defined population of 114,325 residents of Valle d'Aosta in northern Italy. RESULTS: In the first year of the study (January 1-December 31, 1989), 254 cases of first stroke were registered. The crude annual incidence rate was 2.23/1,000, 1.98/1,000 for men and 2.46/1,000 for women. After adjustment to the 1988 Italian population, the incidence rate for first stroke was 2.15/1,000 per year, 2.48/1,000 per year for men and 1.99/1,000 per year for women. The pathological diagnosis was cerebral infarction in 67%, intracranial hemorrhage in 15%, and unknown in 18%. The overall 30-day case-fatality rate was 31%. In survivors, Barthel Index Score recorded at 30 days from stroke onset showed that 100 patients (62%) were dependent in activities of daily living. CONCLUSIONS: Our results do not differ significantly from those reported in Umbria, the only similar study performed in Italy, and support non-Italian data as to risk factors in stroke.

Aged↗