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Biomedical subjects

A Silvestri

Publications and source records attributed to A Silvestri.

At least 19 recordsLinked to original sources
PubMed2006

Constraints on cosmic neutrino fluxes from the Antarctic Impulsive Transient Antenna experiment.

We report new limits on cosmic neutrino fluxes from the test flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment, which completed an 18.4 day flight of a prototype long-duration balloon payload, called ANITA-lite, in early 2004. We search for impulsive events that could be associated with ultrahigh energy neutrino interactions in the ice and derive limits that constrain several models for ultrahigh energy neutrino fluxes and rule out the long-standing -burst model.

Journal Article↗
PubMed2004

Search for extraterrestrial point sources of neutrinos with AMANDA-II.

We present the results of a search for point sources of high-energy neutrinos in the northern hemisphere using AMANDA-II data collected in the year 2000. Included are flux limits on several active-galactic-nuclei blazars, microquasars, magnetars, and other candidate neutrino sources. A search for excesses above a random background of cosmic-ray-induced atmospheric neutrinos and misreconstructed downgoing cosmic-ray muons reveals no statistically significant neutrino point sources. We show that AMANDA-II has achieved the sensitivity required to probe known TeV gamma-ray sources such as the blazar Markarian 501 in its 1997 flaring state at a level where neutrino and gamma-ray fluxes are equal.

Journal Article↗
PubMed2004

Behavioral disturbances in Alzheimer's disease: a non-pharmacological therapeutic approach.

Behavioral disturbances in patients with dementia are among the primary causes of institutionalization. Although the majority of authors agree that such symptoms are well controlled with non-pharmacological support, almost all studies have been focused on symptomatic drug therapy (typical or atypical neuroleptics). The aim of our study was to evaluate the reduction of psychiatric symptoms revealed with the test called empirical behavioral pathology in Alzheimer disease (E-Behave-AD) in a population of patients with AD whose caregivers underwent training to learn various communication strategies to utilize with family members. We evaluated 35 patients with AD (18 males, 17 females, average age 76.5 +/- 5.9 years). Of these patients, 18 (9 males, 9 females, average age 75.1 +/- 6.5 years) were relatives of caregivers who underwent training for six months, four group meetings and two individual ones. During the training, caregivers learned about the possibility of communication with persons with AD. They were taught how to interact with the AD patients in various phases of the illness and how to utilize effectively both verbal and non-verbal language. Other 17 patients (9 males, 8 females, average age 76.1 +/- 4.9 years) were followed as a control group. During the period of observation, all patients were given rivastigmine or donezepil. The two groups were homogenous for age, sex, antipsychotic drug therapy, and initial scores on mini-mental state examination (MMSE), activity of daily living (ADL), instrumental activity of daily living (IADL), and E-Behave-AD. After six months, we evaluated the patients with an analogous battery of tests. The analysis of data proceeded from the verification of homogeneity of test subjects and of the control group with t-test for non-paired data. We used the chi2 statistics to compare the qualitative variables between test subjects and the control group. For all statistical tests, a p < 0.05 was considered significant. In the group of patients with caregivers who underwent training, a statistically significant decrease in the E-Behave-AD score (p < 0.001) was observed after six months (7.7 vs. 10.5; p < 0.001). There was no statistically significant modification in the scores for the ADL, IADL, and MMSE (ADL 4.7 vs. 4.3, p = 0.09; IADL 3.2 vs. 3.1, p =0.4; MMSE 17.3 vs. 15.1, p = 0.1). Numerous evidences in literature underline the centrality of the language deficit in dementia, particularly in AD. A re-establishment, even if partial, of the channels of communication between AD patients and doctors, as well as between patients and caregivers, can reduce the frequency and intensity of behavioral disturbances in persons with AD.

Activities of Daily Living↗
PubMed2004

The management of psychogeriatric patient.

The exponential growth in the prevalence of cognitive impairment of old patients leads the physicians to deal with a larger incidence of behavioral disorders (such as excitement,aggressiveness), and psychotic symptoms (such as delirium and visual hallucinations). The presence of psychotic troubles in dementia causes a remarkable distress to caregivers and involves higher difficulties in the patient management. The estimates of such troubles range between 15 and 75 %. Geriatric assessment and the management of behavioral troubles require a prompt evaluation of all their possible causes. As a matter of fact, their appearance often reveals a physical disturbance (pain, fever, etc.), or adverse environmental conditions, or it could also be a consequence of a multiple drug therapy. For this reason,the use of antipsychotics should always be preceded by an accurate clinical diagnosis.Anxiolytic, anti-depressive, anti-convulsive and anti-psychotic drugs are among the therapeutic strategies for the management of the psychogeriatric patient. Atypical antipsychotics seem to be able to decrease the psychotic symptoms, with low levels of therapeutic failure. They also reduce extrapyramidal effects and the growth of prolactine hormone, which is quite useful when dealing with very old patients. Risperidone and olanzapine are two atypical anti-psychotics, which already proved to be adequate and well tolerated during the treatment of schizophrenia and of acute maniacal disorders. Our experience, with a population of patients followed by our Alzheimer Evaluation Unit (AEU), confirms that a low dose of olanzapine (5mg/day) and risperidone (0.5-1.0 mg/day) are effective in lowering behavioral disturbances, and psychotic symptoms due to dementia. Even in the long run,low doses of these drugs are still well tolerated. Higher levels of risperidone (> 1 mg/die)often caused extra-pyramidal symptoms such as rigidity and dyskinesia, whereas higher levels of olanzapine (> 5 mg/day) lead to an exceeding sedation. The management of behavioral disturbances is one of the most important goals in the global treatment of patients affected by dementia, to the extent of improving the quality of life. Atypical antipsychotics are preferable compared to old-generation drugs, therefore, they are the key therapeutic strategy we cannot renounce.

Activities of Daily Living↗
PubMed2003

Limits on diffuse fluxes of high energy extraterrestrial neutrinos with the AMANDA-B10 detector.

Data from the AMANDA-B10 detector taken during the austral winter of 1997 have been searched for a diffuse flux of high energy extraterrestrial muon neutrinos. This search yielded no excess events above those expected from background atmospheric neutrinos, leading to upper limits on the extraterrestrial neutrino flux measured at the earth. For an assumed E-2 spectrum, a 90% classical confidence level upper limit has been placed at a level E2Phi(E)=8.4 x 10(-7) cm(-2) s(-1) sr(-1) GeV (for a predominant neutrino energy range 6-1000 TeV), which is the most restrictive bound placed by any neutrino detector. Some specific predicted model spectra are excluded. Interpreting these limits in terms of the flux from a cosmological distributions of sources requires the incorporation of neutrino oscillations, typically weakening the limits by a factor of 2.

Journal Article↗
PubMed2003

[Skeletal and occlusal alterations in the diagnosis of Marfan syndrome].

The Marfan syndrome is an autosomal dominant hereditary connective tissue disorder with variable expressivity. The incidence is estimated to be at least 1 case per 10000 individuals in most populations. The syndrome is caused by mutations in the gene coding for Fibrillin-1 (FBN1), an extracellular matrix glyco-protein. The gene responsible for the mutations was identified in the chromosome 15q21.1 region. Presented for the first time in 1896 by Dr Antoine Bernard Marfan, it was subsequently included among hereditary disorders of the connective tissue. Nowadays the Marfan syndrome is considered to be a heterogeneous pathology, that can derive from many mutations in the gene coding for Fibrillin-1. The ocular, cardiovascular and skeletal manifestations present in the individual affected by Marfan syndrome are consistent with a defect in the gene coding for a structural component of the connective tissues. From the different expressivity derive 4 types or variants of the syndrome: a) asthenia; b) non-asthenia; c) arachnodactyly; e) abnormal joint mobility. In this study the authors show that radiography and cephalometry analysis are important as diagnosis techniques in order to make an early diagnosis of Marfan syndrome, carry out differential diagnosis with other maxillo-facial pathologies and correct the therapeutic approach (orthodontic or surgical) of this syndrome.

Abnormalities, Multiple↗
PubMed2001

Observation of high-energy neutrinos using Cerenkov detectors embedded deep in Antarctic ice.

Neutrinos are elementary particles that carry no electric charge and have little mass. As they interact only weakly with other particles, they can penetrate enormous amounts of matter, and therefore have the potential to directly convey astrophysical information from the edge of the Universe and from deep inside the most cataclysmic high-energy regions. The neutrino's great penetrating power, however, also makes this particle difficult to detect. Underground detectors have observed low-energy neutrinos from the Sun and a nearby supernova, as well as neutrinos generated in the Earth's atmosphere. But the very low fluxes of high-energy neutrinos from cosmic sources can be observed only by much larger, expandable detectors in, for example, deep water or ice. Here we report the detection of upwardly propagating atmospheric neutrinos by the ice-based Antarctic muon and neutrino detector array (AMANDA). These results establish a technology with which to build a kilometre-scale neutrino observatory necessary for astrophysical observations.

Journal Article↗
PubMed2001

32-year old patient presenting with autoimmune polyglandular syndrome.

A 32-year-old student reported fatigue and malaise since two months in the absence of specific symptoms. Clinical examination and extensive laboratory testing revealed no abnormalities at his first presentation. Some weeks thereafter, on re-admission, hyperpigmentation suggestive of Addison's disease was observed and pathognomonic autoantibodies directed against the thyroid gland and the adrenal cortex were detected. Further evaluation led to the diagnosis autoimmune polyglandular deficiency syndrome, also named "Schmidt syndrome", comprising adrenocortical insufficiency (Addison's disease) and lymphocytic thyroiditis (Hashimoto thyroiditis). The diagnosis of polyglandular insufficiency is often delayed due to non-specific symptoms at early disease stages and progression may be rapid, culminating in Addisonian crisis under physical stress or infection, requiring immediate high-dose hormone replacement therapy. Hence, careful re-examination is mandatory to ensure adequate treatment before life-threatening complications occur. Nowadays this type of disease is classified as autoimmune polyglandular syndrome type II (APS type II) with an increased risk of developing insulin-dependent diabetes mellitus (IDDM), vitiligo, alopecia, pernicious anaemia, coeliac disease, myasthenia gravis and primary hypogonadism. The cause of the disease remains obscure but in addition to an autosomal dominant trait with variable penetrance some hints at viral infection triggering the disease process exist.

Adult↗
PubMed2001

A multistep process for the dispersal of a Y chromosomal lineage in the Mediterranean area.

In this work we focus on a microsatellite-defined Y-chromosomal lineage (network 1.2) identified by us and reported in previous studies, whose geographic distribution and antiquity appear to be compatible with the Neolithic spread of farmers. Here, we set network 1.2 in the Y-chromosomal phylogenetic tree, date it with respect to other lineages associated with the same movements by other authors, examine its diversity by means of tri- and tetranucleotide loci and discuss the implications in reconstructing the spread of this group of chromosomes in the Mediterranean area. Our results define a tripartite phylogeny within HG 9 (Rosser et al. 2000), with the deepest branching defined by alleles T (Haplogroup Eu10) or G (Haplogroup Eu9) at M172 (Semino et al. 2000), and a subsequent branching within Eu9 defined by network 1.2. Population distributions of HG 9 and network 1.2 show that their occurrence in the surveyed area is not due to the spread of people from a single parental population but, rather, to a process punctuated by at least two phases. Our data identify the wide area of the Balkans, Aegean and Anatolia as the possible homeland harbouring the largest variation within network 1.2. The use of recently proposed tests based on the stepwise mutation model suggests that its spread was associated to a population expansion, with a high rate of male gene flow in the Turkish-Greek area.

Alleles↗
PubMed2001

A pediatric emergency department follow-up system: completing the cycle of care.

BACKGROUND: Prior to 1993, the follow-up program for our pediatric emergency department (ED) was the responsibility of the rotating senior pediatric resident. There were inherent problems with this system, as a consequence of inconsistent personnel. The residents' revolving schedules and the fact that they were accountable to other clinical areas decreased their availability for follow-up. Also, it was difficult for the clerical staff to identify the person responsible for answering parent calls. The medical director of the ED made the decision to turn the core responsibility for the follow-up program to the nurse practitioners in addition to their direct care provider role. The nurse practitioner group is a consistent member of the treatment team who has the critical thinking skills necessary to handle the majority of issues that require follow-up. The emergency attending physicians are available for consultation whenever questions arise. OBJECTIVE: Review of current follow-up program of a pediatric ED and its impact on patient care, patient/parent satisfaction, and communication with community providers and specialists. METHOD: A retrospective review of the evolution of the multi-faceted follow-up of patients from an urban pediatric ED. RESULTS: Antidotal evidence suggests that a comprehensive follow-up program increases patient satisfaction, improves communication between the ED, primary care providers, and specialists. It also decreases the workload of the attending emergency physicians, allowing them more time to focus on acute issues. In addition, the follow-up program for ED patients can decrease the medical /legal risks associated with reporting of delayed laboratory results. CONCLUSION: The next step in further reviewing this program is the development of a satisfaction questionnaire for patient/ families and community providers to quantify their level of satisfaction with the program. A retrospective chart review of the patients who received a follow-up phone call after discharge, and the return visit rate would be another avenue to pursue to validate our antidotal information.

Child↗
PubMed2000

The reliability and variability of SN and PFH reference planes in cephalometric diagnosis and therapeutic planning of dentomaxillofacial malformations.

Various interpretations of clinical and cephalometric data lead to different diagnostic and surgical planning in the study of dentoskeletal malformations. Many authors have identified this discrepancy as an incorrect positioning between the skeletal structures and the Frankfurt plane (PFH)--a plane that is used routinely for the sagittal measurement of the upper and lower jaw. The aim of this study was to establish a control method to verify the correct positioning of the sella-nasion point plane (SN) and the PFH. To find a reference plane, the authors concentrated their attention on measuring the intersecting angles between these two planes and the vertical posterior maxillary (PM) plane. Fifty patients (33 women and 17 men), all of whom were aesthetically and structurally harmonious class I dentoskeletal types, were analyzed using this method. Student's t-test, the Kolmogorov-Smirnov test, and Fisher's F-test were used for statistical analysis. The results were compared with those proposed by the University of Michigan. To achieve a correct diagnosis and to obtain good functional and cosmetic results in the treatment of these kinds of malformations, it is necessary to make use of the PM vertical plane during cephalometric analysis.

Adolescent↗
PubMed2000

[Treatment of mandibular condylar hyperplasia in developmental age. Clinical case].

A case of hyperplasia of the mandibular condyle in a growing-up subject, observed at the Department of Maxillo-Facial Surgery of the University of Rome "La Sapienza", is described. Hyperplasia of the mandibular condyle is a facial asymmetry due to the unilateral overdevelopment of the mandibular bone. In this study the authors underline how bone scintigraphy, 3D tomography and electrognatographic analysis, associated with standard radiography and cephalometry, are important methods of diagnosis in order to make an early diagnosis of hyperplasia of the mandibular condyle and differential diagnosis with other pathologies. In particular, bone scintigraphy is a useful screening procedure to detect if the pathology is in an active phase or not. The 3D tomography is used in pre-surgery to evaluate precisely morphological and structural alterations of the craniofacial bones on a tridimentional base. Finally, the electrognatographic test records the mandibular activity both in physiological and pathological conditions. All these instrumental techniques allow to make a diagnosis and lead to a possible therapeutical approach.

Adolescent↗
PubMed1999

Domain interactions affecting human DNA topoisomerase I catalysis and camptothecin sensitivity.

DNA topoisomerase I (Top1p) relaxes supercoiled DNA by the formation of a covalent intermediate in which the active site tyrosine is transiently bound to the severed DNA strand. The antineoplastic agent camptothecin (Cpt) specifically targets Top1p and several mutations have been isolated that render the enzyme Cpt resistant. The mutated residues, although located in different regions of the enzyme, may constitute part of the Cpt binding site. To begin identifying the structural features of DNA Top1p important for Cpt-induced cytotoxicity, we developed a novel yeast genetic screen to isolate catalytically active, yet Cpt-resistant enzymes from a pool of human top1 mutants. Among the mutations isolated were substitutions of Ser or Val for Gly363, which like the Gly363 to Cys mutation previously reported by us, suppressed the Cpt sensitivity of Top1p. In contrast, each amino-acid substitution differed in its ability to suppress the lethal phenotype and catalytic activity of a human top1 mutant top1T718A that resembles Cpt by stabilizing the covalent intermediate. Biochemical analyses and molecular modeling support a model where interactions between two conserved domains, a central "lip" region containing residue Gly363 and the residues around the active site tyrosine (Tyr723), directly affect the formation of the Cpt-binding site and enzyme catalysis.

Alanine↗
PubMed1997

Study of yeast DNA topoisomerase II and its truncation derivatives by transmission electron microscopy.

The 1429-amino acid residue long yeast DNA topoisomerase II and three of its deletion derivatives, a C-terminal truncation containing residues 1-1202, a 92-kDa fragment spanning residues 410-1202, and an A'-fragment spanning residues 660-1202, were examined by transmission electron microscopy. Analysis of rotary-shadowed images of these molecules shows that the full-length enzyme assumes a tripartite structure, in which a large globular core comprising the carboxyl parts of the dimeric enzyme is connected to a pair of smaller spherical masses comprising the ATPase domains of the enzyme. The linkers bridging the large globular structure and each of the smaller spheres are not visible in most of the images but appear to be sufficiently stiff to keep the relative positions of the connected parts. The angle extended by the pair of spherical masses is variable and falls in a range of 50-100 degrees for the majority of the images. On binding of a nonhydrolyzable ATP analog to the enzyme, this angle is significantly reduced as the two spherical masses swing into contact. These observations, together with results from previous biochemical and x-ray crystallographic studies of the enzyme, provide a sketch of the molecular architecture and conformational states of a catalytically active type II DNA topoisomerase.

DNA Topoisomerases, Type II↗
PubMed1997

[Proposed medical record to be used in rape cases. New diagnostic and medicolegal aspects].

The latest report of 1996 on human development in the UN development programme (UNDP) states that 130,000 women are raped every year in the industrialized countries. Illegal "violation" is defined as the sexual penetration of any orifice of the body without the victim's consent. The doctor's contribution is essential in order to ascertain this offence. It can be divided into two stages: precise and complete (... missing? ...) information regarding the sexual aggression which might have taken the form of rape. Management of a rape case represents an extremely complex undertaking for the doctor since it involves medical and legal aspects and requires a number of interventions that lead to a rational evaluation and appropriate treatment. In this context, the doctor's role is not only to protect the psychophysical integrity of the victim, but also to contribute, following an early diagnosis of sexual aggression, to the identification of the particulars of an offence which still risks remaining unpunished, owing to the difficulty of diagnosis and in spite of the recent enactment of Law no. 66 on 15 February 1996. The medical record proposed by the authors consists of a descriptive anamnestic part and a graphic part, thus making the evaluation of the victim more rapid and precise. The proposed medical record is subdivided into anamnesis, objective examination, psychological examination, laboratory tests, any consultancy requested and therapy.

Female↗