Showing papers by "University of Siena published in 1999"

Interim Report and Recommendations of the World Health Organization Task-Force for Osteoporosis

Abstract: Harry K. Genant (Chairman) , Cyrus Cooper (Rapporteur) , Gyula Poor (Rapporteur) , Ian Reid (Rapporteur) , George Ehrlich (Editor), J. Kanis (Editor), B. E. Christopher Nordin (Editor), Elizabet h Barrett-Connor , Dennis Black, J.-P. Bonjour, Bess Dawson-Hughes , Pierre D. Delmas, J. Dequeker , Sergio Ragi Eis, Carlo Gennari , Olaf Johnell , C. Conrad Johnston, Jr, Edith M. C. Lau, Uri A. Liberman, Robert Lindsay, Thomas John Martin, Basel Masri, Carlos A. Mautalen, Pierre J. Meunier, Paul D. Miller , Ambrish Mithal, Hirotoshi Morii , Socrates Papapoul os, Anthony Woolf, Wei Yu and Nikolai Khaltaev (WHO Secretariat) 30

Cloning and Characterization of blaVIM, a New Integron-Borne Metallo-β-Lactamase Gene from a Pseudomonas aeruginosa Clinical Isolate

Abstract: Production of a metallo-β-lactamase activity was detected in a carbapenem-resistant Pseudomonas aeruginosa clinical isolate (isolate VR-143/97) from an Italian inpatient at the Verona University Hospital (northern Italy). The metallo-β-lactamase determinant was isolated from a genomic library of VR-143/97, constructed in an Escherichia coli plasmid vector, by screening for clones with reduced susceptibility to imipenem. Sequencing of the cloned gene revealed that it encoded a new class B β-lactamase that was named VIM-1. At the sequence level VIM-1 was rather divergent from the other class B enzymes (16.4 to 38.7% identity), overall being more similar to members of subclass B1 including the β-lactamase II of Bacillus cereus (Bc-II), the Bacteroides fragilis CcrA, the Chryseobacterium meningosepticum BlaB, and the cassette-encoded IMP-1 enzymes. Among these, VIM-1 showed the highest degree of similarity to Bc-II. Similarly to blaIMP, blaVIM was also found to be carried on a gene cassette inserted into a class 1 integron. The blaVIM-containing integron was located on the chromosome of P. aeruginosa VR-143/97, and the metallo-β-lactamase-encoding determinant was not transferable to E. coli by conjugation. Expression of the integron-borne blaVIM gene in E. coli resulted in a significant decrease in susceptibility to a broad array of β-lactams (ampicillin, carbenicillin, piperacillin, mezlocillin, cefotaxime, cefoxitin, ceftazidime, cefoperazone, cefepime, and carbapenems), revealing a very broad substrate specificity of the VIM-1 enzyme.

Risk Factors for Hip Fracture in Men from Southern Europe: The MEDOS Study

Abstract: The aims of this study were to identify risk factors for hip fracture in men aged 50 years or more. We identified 730 men with hip fracture from 14 centers from Portugal, Spain, France, Italy, Greece and Turkey during the course of a prospective study of hip fracture incidence and 1132 age-stratified controls selected from the neighborhood or population registers. The questionnaire examined aspects of work, physical activity past and present, diseases and drugs, height, weight, indices of co-morbidity and consumption of tobacco, alcohol, calcium, coffee and tea. Significant risk factors identified by univariate analysis included low body mass index (BMI), low sunlight exposure, a low degree of recreational physical activity, low consumption of milk and cheese, and a poor mental score. Co-morbidity including sleep disturbances, loss of weight, impaired mental status and poor appetite were also significant risk factors. Previous stroke with hemiplegia, prior fragility fractures, senile dementia, alcoholism and gastrectomy were associated with significant risk, whereas osteoarthrosis, nephrolithiasis and myocardial infarction were associated with lower risks. Taking medications was not associated with a difference in risk apart from a protective effect with the use of analgesics independent of co-existing osteoarthrosis and an increased risk with the use of anti-epileptic agents. Of the potentially ‘reversible’ risk factors, BMI, leisure exercise, exposure to sunlight and consumption of tea and alcohol and tobacco remained independent risk factors after multivariate analysis, accounting for 54% of hip fractures. Excluding BMI, 46% of fractures could be explained on the basis of the risk factors sought. Of the remaining factors low exposure to sunlight and decreased physical activity accounted for the highest attributable risks (14% and 9% respectively). The use of risk factors to predict hip fractures had relatively low sensitivity and specificity (59.6% and 61.0% respectively). We conclude that lifestyle factors are associated with significant differences in the risk of hip fracture. Potentially remediable factors including a low degree of physical exercise and a low BMI account for a large component of the total risk.

Coronally Advanced Flap Procedure for Root Coverage. Is Flap Thickness a Relevant Predictor to Achieve Root Coverage? A 19-Case Series

Abstract: This clinical study was designed to determine whether the thickness of the flap can influence root coverage when gingival recessions associated with traumatic toothbrushing are treated using a coronally advanced flap (CAF). Nineteen patients, aged from 25 to 57 years, with high levels of oral hygiene (full-mouth plaque scores or =2 mm were treated. After local anesthesia and before flap elevation, the exposed root surface was planed with a sharp curet. A trapezoidal full- and partial-thickness flap was then elevated, displaced coronally, and sutured to cover the treated root surface. Before suturing, flap thickness was measured in the alveolar mucosa with a gauge. After surgery, all patients were recalled for control and professional prophylaxis once a week during the first month and monthly up to the third month. The mean initial recession depth was 3.0+/-0.9 mm. Mean flap thickness (FT) was 0.7+/-0.2 mm. Three months later, mean recession depth was 0.6+/-0.6 (P 0.8 mm was associated with 100% of root coverage. The results of this study indicate that there is a direct relation between flap thickness and recession reduction (P <0.0001).

c-fos-induced growth factor/vascular endothelial growth factor D induces angiogenesis in vivo and in vitro

Abstract: c-fos-induced growth factor/vascular endothelial growth factor D (Figf/Vegf-D) is a secreted factor of the VEGF family that binds to the vessel and lymphatic receptors VEGFR-2 and VEGFR-3. Here we report that Figf/Vegf-D is a potent angiogenic factor in rabbit cornea in vivo in a dose-dependent manner. In vitro Figf/Vegf-D induces tyrosine phosphorylation of VEGFR-2 and VEGFR-3 in primary human umbilical cord vein endothelial cells (HUVECs) and in an immortal cell line derived from Kaposi’s sarcoma lesion (KS-IMM). The treatment of HUVECs with Figf/Vegf-D induces dose-dependent cell growth. Figf/VEGF-D also induces HUVEC elongation and branching to form an extensive network of capillary-like cords in three-dimensional matrix. In KS-IMM cells Figf/Vegf-D treatment results in dose-dependent mitogenic and motogenic activities. Taken together with the previous observations that Figf/Vegf-D expression is under the control of the nuclear oncogene c-fos, our data uncover a link between a nuclear oncogene and angiogenesis, suggesting that Figf/Vegf-D may play a critical role in tumor cell growth and invasion.

Testing the Robustness of the Likelihood-Ratio Test in a Variance-Component Quantitative-Trait Loci–Mapping Procedure

Abstract: Detection of linkage to genes for quantitative traits remains a challenging task. Recently, variance components (VC) techniques have emerged as among the more powerful of available methods. As often implemented, such techniques require assumptions about the phenotypic distribution. Usually, multivariate normality is assumed. However, several factors may lead to markedly nonnormal phenotypic data, including (a) the presence of a major gene (not necessarily linked to the markers under study), (b) some types of gene x environment interaction, (c) use of a dichotomous phenotype (i.e., affected vs. unaffected), (d) nonnormality of the population within-genotype (residual) distribution, and (e) selective (extreme) sampling. Using simulation, we have investigated, for sib-pair studies, the robustness of the likelihood-ratio test for a VC quantitative-trait locus-detection procedure to violations of normality that are due to these factors. Results showed (a) that some types of nonnormality, such as leptokurtosis, produced type I error rates in excess of the nominal, or alpha, levels whereas others did not; and (b) that the degree of type I error-rate inflation appears to be directly related to the residual sibling correlation. Potential solutions to this problem are discussed. Investigators contemplating use of this VC procedure are encouraged to provide evidence that their trait data are normally distributed, to employ a procedure that allows for nonnormal data, or to consider implementation of permutation tests.

Biochemical characterization of the Pseudomonas aeruginosa 101/1477 metallo-beta-lactamase IMP-1 produced by Escherichia coli.

Abstract: The blaIMP gene coding for the IMP-1 metallo-beta-lactamase produced by a Pseudomonas aeruginosa clinical isolate (isolate 101/1477) was overexpressed via a T7 expression system in Escherichia coli BL21 (DE3), and its product was purified to homogeneity with a final yield of 35 mg/liter of culture. The structural and functional properties of the enzyme purified from E. coli were identical to those of the enzyme produced by P. aeruginosa. The IMP-1 metallo-beta-lactamase exhibits a broad-spectrum activity profile that includes activity against penicillins, cephalosporins, cephamycins, oxacephamycins, and carbapenems. Only monobactams escape its action. The enzyme activity was inhibited by metal chelators, of which 1,10-o-phenanthroline and dipicolinic acid were the most efficient. Two zinc-binding sites were found. The zinc content of the P. aeruginosa 101/1477 metallo-beta-lactamase was not pH dependent.

Corticospinal Excitability Modulation to Hand Muscles During Movement Imagery

Abstract: Motor evoked potentials (MEPs) to magnetic transcranial stimulation (TCS) were recorded from right abductor digiti minimi (ADM) and first dorsal interosseous (FDI) muscles, sharing the same peripheral innervation but engaged in two different motor demands. In seven healthy and trained subjects, the latencies, amplitudes and variability of MEPs were investigated under the following, randomly intermingled, conditions: full muscular and mental relaxation; mental simulation of selective index finger or little finger abduction; mental non-motor activity (arithmetical calculation); and real motor task (little and index finger abduction). The whole procedure was performed by continuous audiovisual monitoring of electromyographic 'silence' in the tested muscles. The maximal facilitatory effects (= latency shortening and amplitude increase) on MEPs were induced by the real motor task. An amplitude potentiation of MEPs in both tested muscles was present during non-motor mental activity, in comparison to basal values. A further amplitude potentiation, without latency shifts, was confined to the muscle acting as 'prime mover' for the mentally simulated movement, according to the motor program dispatched but not executed by the subject. Similar results were also found in the F-wave, showing that mental simulation affects spinal motoneuronal excitability as well, although -- due to the lack of MEP and F-wave latency shift -- the main effect takes place at cortical level. The study shows that movement imagery can focus specific facilitation on the prime-mover muscle for the mentally simulated movement. This is mainly evident on FDI muscle, which controls fingers (i.e. the index) with highly corticalized motor representation.

Intermittent loading of teeth restored using quartz fiber, carbon-quartz fiber, and zirconium dioxide ceramic root canal posts.

Abstract: Purpose The purpose of the investigation was to compare the performances of teeth restored with quartz fiber, carbon-quartz fiber, and zirconium-dioxide posts covered with all-ceramic crowns when subjected to a cyclic loading test performed in a wet environment. Materials and methods Forty single-rooted human lower premolars having similar dimensions were endodontically treated and mounted in acrylic resin blocks with a simulated periodontal ligament. The teeth were divided into three experimental groups and one control group. Post holes 8 mm long were prepared in the roots of the experimental groups in which quartz fiber, carbon-quartz fiber, and zirconium dioxide posts were cemented. In the control group, no posts were used. The crown buildup was made with composite resin. The teeth were covered with all-ceramic crowns and intermittently loaded at an angle of 45 degrees to the long axis of the tooth at a frequency of two loads per second. Results Only one failure (root fracture + post fracture) was observed in each of the fiber post groups, while in the zirconium dioxide post group, six failures were observed (one crown fracture and 5 root fractures + post fractures). The Kaplan-Meier analysis of the three experimental groups showed that the survival rate of zirconium dioxide posts was significantly lower than that of both types of fiber post. All the experimental groups showed a survival rate higher than that of the control group. Conclusion Fiber posts reduced to a minimum the risk of root fractures of teeth restored with composite cores and Empress crowns under the present experimental conditions (intermittent loading in a wet environment).

A new CACNA1A gene mutation in acetazolamide-responsive familial hemiplegic migraine and ataxia

Abstract: Objective: To search for mutations in the calcium channel gene CACNA1A and to study the genotype–phenotype correlation in a family with a severe familial hemiplegic migraine (FHM) phenotype and a slowly progressive cerebellar ataxia. Background: CACNA1A gene mutations on chromosome 19 are involved in approximately 50% of FHM families. The association of FHM and cerebellar ataxia has been reported in a small number of FHM families, all linked to chromosome 19. Methods: The proband, in addition to typical hemiplegic migraine attacks, experienced severe episodes during which hemiplegia was associated with acutely altered consciousness and fever lasting several days. She, as well as her affected sister, developed a permanent, late-onset cerebellar ataxia and cerebellar atrophy evident on MRI. Linkage analysis was performed and the whole CACNA1A gene, 47 exon–intron boundaries, was analyzed by double gradient–denaturing gradient gel electrophoresis (DG-DGGE). Results: Genetic studies suggested linkage to chromosome 19p13, and DG-DGGE analysis detected a heteroduplex fragment in exon 13 of the CACNA1A gene. By direct sequencing, a G-to-A substitution resulting in an arginine to glutamine change at codon 583 in the second putative voltage sensor domain of the channel α 1A -subunit, was identified, possibly representing the disease-causing mutation. The proband and her affected sister were treated with acetazolamide, reporting freedom from new FHM attacks but no benefit in the progression of ataxia. Conclusions: The combination of episodic dysfunction and permanent deficit could depend on the variety of functions of calcium channels and their distribution in the nervous system.

Biological and clinical effects of ozone. Has ozone therapy a future in medicine

Abstract: Although ozone therapy has been used as an alternative medical approach for four decades, it has encountered scepticism, if not outright objection, by orthodox medicine. This prejudice is not unjustified because ozone therapy often has been used without rational basis or appropriate controls. With the advent of precise medical ozone generators, it is now possible to evaluate some mechanisms of action and possible toxicity. In contrast with the respiratory tract, human blood exposed to appropriate ozone concentrations is able to tame its strong oxidant properties and neither acute nor chronic side effects have ensued in millions of patients treated with ozonated autohaemotherapy. This paper summarises studies aimed at clarifying biological effects, defining any possible damage, the therapeutic window, and suitable doses able to express therapeutic activity. Although an unfashionable and unpopular approach, it is hoped that orthodox medicine will help to critically assess the validity of ozone therapy.

Treatment of hypertrophy of the inferior turbinate: long-term results in 382 patients randomly assigned to therapy.

Abstract: A number of surgical techniques are commonly performed to control the symptoms of inferior turbinate hypertrophy unresponsive to medical treatment. We report long-term results in 382 patients randomly assigned to receive electrocautery (62), cryotherapy (58), laser cautery (54), submucosal resection without lateral displacement (69), submucosal resection with lateral displacement (94), and turbinectomy (45). Outcomes of objective test results from rhinomanometry, acoustic rhinometry, mucociliary transport time, and secretory immunoglobulin A levels were compared to the symptom scores before and yearly after surgical treatment. These data indicate that submucosal resection with lateral displacement of the inferior turbinate results in the greatest increases in airflow and nasal respiratory function with the lowest risk of long-term complications.

Perinatal exposure to the estrogenic pollutant bisphenol A affects behavior in male and female rats.

Abstract: Bisphenol A (BPA) is an environmental estrogen with potentially aversive effects on public health. In rats, we studied the effects of perinatal exposure to BPA on nonsocial behaviors partly influenced by gonadal hormones. BPA was administered orally to one group of mother rats at a concentration within the range of human exposure from 10 days before mating until the weaning of the pups. In a second group, BPA was given at a higher dosage during a critical period for brain organization, i.e., from day 14 of gestation until day 6 after birth. The offspring of the treated mothers were tested in the holeboard and the elevated plus-maze at 85 days of age. Various aspects of nonsocial behavior were affected by BPA, differently in males and females, confirming that exposure to a weak environmental estrogen in the period of sexual differentiation of the brain can influence adult behavior. However, contrary to our expectation, a clear masculinization of females was not observed. In general, the factor analysis indicated that in treated males both the motivation to explore and anxiety are reduced, while in females, motor activity and motivation to explore are depressed. Because there were no substantial differences between the two modalities of BPA administration, we suggest that the prolonged treatment with the low dosage compensates for the higher dosage given during a shorter steroid-sensitive period. This may be a cause of concern for public health, given the greater incidence of prolonged exposure of humans to low concentrations released into the environment.

Deletion of the ryanodine receptor type 3 (RyR3) impairs forms of synaptic plasticity and spatial learning

Abstract: Deletion of the ryanodine receptor type 3 (RyR3) results in specific changes in hippocampal synaptic plasticity, without affecting hippocampal morphology, basal synaptic transmission or presynaptic function. Robust long-term potentiation (LTP) induced by repeated, strong tetanization in the CA1 region and in the dentate gyrus was unaltered in hippocampal slices in vitro, whereas weak forms of plasticity generated by either a single weak tetanization or depotentiation of a robust LTP were impaired. These distinct physiological deficits were paralleled by a reduced flexibility in re- learning a new target in the water-maze. In contrast, learning performance in the acquisition phase and during probe trial did not differ between the mutants and their wild-type littermates. In the open-field, RyR3 -/- mice displayed a normal exploration and habituation, but had an increased speed of locomotion and a mild tendency to circular running. The observed physiological and behavioral effects implicate RyR3- mediated Ca 21 release in the intracellular processes underlying spatial learning and hippocampal synaptic plasticity.

Hydrogen peroxide produced during γ-glutamyl transpeptidase activity is involved in prevention of apoptosis and maintainance of proliferation in U937 cells

Abstract: It has been reported in several cell lines that exposure to low levels of reactive oxygen species can exert a stimulatory effect on their proliferation. We have previously shown that mild oxidative conditions can also counteract apoptotic stimuli. A constitutive cellular production of low levels of superoxide and hydrogen peroxide originates from various sources; among these, γ-glutamyl transpeptidase (GGT), the plasma membrane-bound activity in charge of metabolizing extracellular reduced glutathione, has recently been included. Since the inhibition of GGT is a sufficient stimulus for the induction of apoptosis in selected cell lines, we investigated whether this effect might result from the suppression of the mentioned GGT-dependent prooxidant reactions, on the theory that the latter may represent a basal antiapoptotic and proliferative signal for the cell. Experiments showed that: 1) GGT activity in U937 monoblastoid cells is associated with the production of low levels of hydrogen peroxide, and two in...

High rate of mosaicism in tuberous sclerosis complex.

Abstract: Six families with mosaicism are identified in a series of 62 unrelated families with a mutation in one of the two tuberous sclerosis complex (TSC) genes, TSC1 or TSC2. In five families, somatic mosaicism was present in a mildly affected parent of an index patient. In one family with clinically unaffected parents, gonadal mosaicism was detected after TSC was found in three children. The detection of mosaicism has consequences for genetic counseling of the families involved, as changed risks apply to individuals with mosaicism, both siblings and parents. Clinical investigation of parents of patients with seemingly sporadic mutations is essential to determine their residual chance of gonadal and/or somatic mosaicism, unless a mosaic pattern is detected in the index patient, proving a de novo event. In our data set, the exclusion of signs of TSC in the parents of a patient with TSC reduced the chance of one of the parents to be a (mosaic) mutation carrier from 10% to 2%. In the five families with somatic mosaicism, the parent was given the diagnosis after the diagnosis was made in the child.

Structure of In31, a blaIMP-containing Pseudomonas aeruginosa integron phyletically related to In5, which carries an unusual array of gene cassettes

Abstract: The location and environment of the acquired blaIMP gene, which encodes the IMP-1 metallo-β-lactamase, were investigated in a Japanese Pseudomonas aeruginosa clinical isolate (isolate 101/1477) that produced the enzyme. In this isolate, blaIMP was carried on a 36-kb plasmid, and similar to the identical alleles found in Serratia marcescens and Klebsiella pneumoniae clinical isolates, it was located on a mobile gene cassette inserted into an integron. The entire structure of this integron, named In31, was determined. In31 is a class 1 element belonging to the same group of defective transposon derivatives that originated from Tn402-like ancestors such as In0, In2, and In5. The general structure of In31 appeared to be most closely related to that of In5 from pSCH884, suggesting a recent common phylogeny for these two elements. In In31, the blaIMP cassette is the first of an array of five gene cassettes that also includes an aacA4 cassette and three original cassettes that have never been described in other integrons. The novel cassettes carry, respectively, (i) a new chloramphenicol acetyltransferase-encoding allele of the catB family, (ii) a qac allele encoding a new member of the small multidrug resistance family of proteins, and (iii) an open reading frame encoding a protein of unknown function. All the resistance genes carried on cassettes inserted in In31 were found to be functional in decreasing the in vitro susceptibilities of host strains to the corresponding antimicrobial agents.

A comparative analysis of left and right dislocation in Romance

Abstract: L'A. examine les decalages existant dans les contructions avec dislocation des clitiques a gauche et a droite dans les langues romanes. Apres avoir souligne l'inadequation de l'hypothese du miroir pour expliquer ces decalages, il montre que l'analyse alternative de Kayne est mieux adaptee, mais qu'elle ne permet de rendre compte que d'un sous-ensemble de decalages et qu'elle souffre d'un defaut fondamental, celui de violer la condition du liage propre, en vigueur dans les constructions romanes. Il propose alors sa propre analyse qui se base sur le fait que le XP deplace vers la droite occupe une position hierarchiquement basse dans la representation arborescente de la phrase, et montre que le XP deplace vers la droite occupe une position de specificateur pour la gauche et qu'il n'est absolument pas adjoint a droite du SV, comme certains ont pu le pretendre

Origin of microsatellite instability in gastric cancer.

Abstract: Microsatellite instability (MSI) is observed in 13-44% of gastric carcinoma. The etiology of MSI in gastric carcinoma has not been clearly defined. To assess the role of mismatch repair in the development of MSI in gastric cancer, expression of hMSH2 and hMLH1 was explored. We examined 117 gastric carcinomas for MSI and observed instability at one or more loci in 19 (16%) of these tumors. Of the 19 tumors with MSI, nine exhibited low-rate MSI (MSI-L) with instability at 33% of loci examined. Immunohistochemical staining for hMLH1 and hMSH2 was performed on eight of the tumors with MSI-H, five with MSI-L, and 15 tumors without MSI. All eight tumors with MSI-H showed loss of staining for either hMLH1 (n = 5) or hMSH2 (n = 3). In contrast, tumors with MSI-L or without MSI all showed normal hMSH2 and hMLH1 protein expression patterns. Moreover, all eight of the tumors with MSI-H also showed instability at BAT-26, whereas none of the MSI-L tumors or tumors without instability showed instability at BAT-26. These findings suggest that the majority of high-level MSI in gastric cancer is associated with defects of the mismatch repair pathway. Although larger studies are needed, BAT-26 appears to be a sensitive and specific marker for the MSI-H phenotype in gastric carcinoma.

Prognostic significance of CEA, CA 19-9 and CA 72-4 preoperative serum levels in gastric carcinoma.

Abstract: The prognostic value of preoperative serum levels of CEA, CA 19-9 and CA 72-4 tumor markers was investigated in 153 patients resected for gastric cancer. The positivity rates for CEA, CA 19-9 and CA 7