Biomedical subjects

G Fadda

Publications and source records attributed to G Fadda.

At least 37 records · Page 2Linked to original sources

PubMed2003

Coexistence of a parathyroid adenoma and parathyroid cyst causing primary hyperparathyroidism.

The association of a functional parathyroid cyst with a parathyroid adenoma is an uncommon finding. In this report we describe the clinical history of a 60-yr-old man, presenting with the following findings: hypercalcemia (18.9 mg/dl), elevated serum parathormone levels (1320 pg/dl), hypercalciuria (228 mg/dl), and hyperphosphaturia (155 mg/dl). Neck ultrasound, magnetic resonance imaging (MRI) and 99Tc Sestamibi scintigraphy led to the identification of a left parathyroid adenoma, located at the lower pole of the left thyroid gland lobe, associated with a parathyroid cyst, located at the upper extremity of the same thyroid lobe. Parathyroidectomy was performed and the histological examination confirmed the diagnosis of a parathyroid adenoma with aspects of cystic degeneration and an upper parathyroid cyst. Analysis of the crystal clear intracystic fluid showed elevated parathyroid hormone (PTH) levels (137.000 pg/ml). The patient is normocalcemic at 2 yr after surgery without signs of recurrent parathyroid enlargements. Aetiology, diagnosis and management of parathyroid cyst will be discussed.

Adenoma↗

PubMed2003

Age-specific seroprevalence of Human Herpesvirus 8 in Mediterranean regions.

OBJECTIVE: Human herpesvirus 8 (HHV8) is believed to be transmitted mainly by sexual contact; epidemiological data from Africa show, however, that non-sexual transmission routes may also play an important role. To evaluate better the distribution of HHV8 infection in the Mediterranean area, we performed an age-specific seroprevalence study. METHODS: Sera were collected from subjects from different geographical areas. The sera were analyzed by immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA). A total of 1083 patients were studied, 667 patients from various regions of Italy and 416 from Albania. The patients were stratified into six age groups. Multivariate logistic regression was used to evaluate associations between HHV8 and demographic data. RESULTS: An overall seropositivity rate of 17.6% was observed. The highest rate was observed in Sardinia (25.0%) and the lowest was found in Albania (13.9%). The prevalence rate increased linearly with age, from 9.7% in patients belonging to the 0-14 years age group to 26.3% for patients more than 59 years old. Seropositivity for HHV8 was significantly associated with membership of the 59 years-plus age group. Rates of seropositivity were significantly higher in patients from central southern Italy (OR = 1.7) and Sardinia (OR = 1.8) than in patients from Albania. CONCLUSIONS: The data suggest that HHV8 is widespread in the Mediterranean area, including regions like Albania that have not been previously investigated. The statistically significant association between HHV8 seropositivitity and increasing age suggests that non-sexual transmission routes may be involved in the spread of the virus.

Adolescent↗

PubMed2003

Incidence of virulence determinants in clinical Enterococcus faecium and Enterococcus faecalis isolates collected in Sardinia (Italy).

Enterococci are widely distributed in the environment; within the human body, they are normal commensals of the oral cavity, gastrointestinal tract and vagina. In recent years, enterococci have become one of the most frequent causes of acquired nosocomial infections worldwide. The molecular mechanism of virulence of these bacteria is still not completely understood. The aims of this work were to characterize phenotypically 47 isolates of Enterococcus faecalis and Enterococcus faecium collected in Sardinia (Italy) by their abilities to adhere to different epithelial cell lines (Vero and Caco-2 cells) and to associate their phenotypes with the presence of known virulence genes detected within their genomes by PCR. The following genes were amplified: AS (aggregation substance), esp (surface protein gene), ace (accessory colonization factor), efaA (E. faecalis endocarditis antigen) and gelE (gelatinase). The virulence genes were detected in E. faecalis isolates only, with the exception of esp, which was found in both species. The phenotypic and genotypic results were also compared with the susceptibility of isolates to various antibiotics.

Antigens, Bacterial↗

PubMed2003

Impact of highly active antiretroviral therapy (HAART) on the incidence of bacterial infections in HIV-infected subjects.

The aim of this study was to evaluate the effect of highly active antiretroviral therapy (HAART) on the incidence of bacterial infections in HIV-infected patients. Two time periods were compared: (A) January 1992-December 1995 (before HAART) and (B) January 1997-December 2000 (after HAART). During the study periods, we observed 931 patients with bacterial infections, i.e. 322 with bacteremia, 369 with bacterial pneumonia and 240 with urinary tract infections, out of 4,242 HIV-infected subjects admitted to the Department of Infectious Diseases of a large university hospital. By comparing the overall incidence of bacterial infections during periods A and B, a statistically significant difference, from 32% to 18% (p<0.01), was observed. Analysis of risk factors of community- and hospital-acquired bacterial infections did not significantly differ in the two study periods. This study establishes that a significant reduction in bacterial infection incidence occurred in HIV-infected subjects when HAART became the standard therapy for HIV infection.

Adult↗

PubMed2003

HHV 8 seroprevalence and transmission within Albanian family groups.

The recently discovered Human Herpesvirus 8 (HHV 8) is associated with all clinical forms of Kaposi's sarcoma. While early research suggested that the virus was transmitted sexually and that it was present only in KS patients, more recent studies seem to show that infection with the virus is more common than once thought, presenting differing distribution patterns in different geographical areas. In this study we analyze seroprevalence and transmission of HHV 8 in a sample of 86 family groups from Albania. Participants were selected among families requesting routine pre-expatriation medical examinations at the Poliambulatorio Padre "L. Monti" in Tirana. Specimens were collected from 180 healthy individuals and tested for the presence of a specific antibody. Antibody anti-HHV-8 detection was performed by immunofluorescence assay (IFA) and enzyme-linked immunosorbent assay (ELISA). The study found an overall rate of HHV 8 seroprevalence of 20.0%. In 4.5% of couples the male and female were both positive, in 30.2% at least one partner was positive; (in 17.4% only the male was positive; in 12.8% only the female). These results support the hypothesis that HHV 8 spreads via multiple transmission routes.

Adolescent↗

PubMed2003

A molecular method for the recovery and identification of enteric virus in shellfish.

In this paper we report the results of an investigation into the presence of enteric viruses in shellfish from the waters around Sardinia. Twenty two samples of shellfish were examined using a rapid and sensitive technique to concentrate and detect viral RNA in shellfish tissues. After recovery of viral particles, RNA was extracted, transcribed into cDNA and amplified using "nested PCR". Testing with enterovirus-specific RT-PCR produced positive results in over 13% of specimens. The virus detection procedure appears to be effective. In some circumstances it could be a better test of water quality than conventional monitoring techniques.

Bacteria↗

PubMed2003

Correlation between fine needle aspiration biopsy and histologic findings in parotid masses. Personal experience.

Pre-operative fine-needle aspiration biopsy findings have been compared with those of post-operative histopathology in 146 patients with parotid masses. Post-operative histology showed 124 benign and 22 malignant lesions: pre-operative fine-needle aspiration biopsy correctly identified 118/124 (95.1%) benign masses with an accurate classification of the tumour in 111/118 cases (94%). Fine-needle aspiration biopsy identified malignancy in 12/22 cases (>50%). In the remaining 7 cases (six benign lesions and one malignant), cytology was not diagnostic. There were no false positive cases. In the present study, the accuracy, sensitivity and specificity of cytologic findings were, respectively, 94%, 57.2% and 100%. The accuracy of fine-needle aspiration biopsy was seen to be higher in benign than in malignant lesions. Fine-needle aspiration biopsy represents a first choice diagnostic tool for the study of palpable head and neck masses excluding abscesses and vascular neoplasms. However, for a correct diagnosis, great skill is required and cytology does not always reach the sensitivity and specificity of post-operative histology. Therefore, in the presence of a palpable head and neck mass, resistant to medical treatment, surgery is still strongly indicated and cytology is very useful in planning the surgical approach.

Adolescent↗

PubMed2002

Distribution of virulence genes in Aeromonas spp. isolated from Sardinian waters and from patients with diarrhoea.

AIMS: To characterize 46 isolates of different Aeromonas spp. strains (26 Aeromonas hydrophila, 13 Aeromonas sobria and 7 Aeromonas salmonicida) isolated from coastal water and clinical sources in Sardinia, Italy. METHODS AND RESULTS: The isolates were analysed for the production of the following virulence properties: slime, haemolysin, gelatinase and protease production, and adhesion to eucaryotic epithelial cells. The presence of known virulence genes: A. hydrophila cytolytic enterotoxin gene AHCYTOEN; type IV pilus gene Tap; Bundle forming pilus genes BfpA and BfpG were investigated using polymerase chain reaction (PCR). In addition the enterobacterial repetitive intergenic consensus sequences (ERIC)-PCR fingerprinting was used to further differentiate the strains. CONCLUSIONS: This study confirms the presence of virulent Aeromonas strains in the Mediterranean sea. The study also found a greater prevalence of haemolysin, protease and gelatinase production, as well as a higher adhesion capacity, among strains isolated from patients with diarrhoea. SIGNIFICANCE AND IMPACT OF THE STUDY: This is the first time that Aeromonads have been isolated and characterized from Sardinian waters and from patients with diarrhoea in Sardinia. This study adds to our knowledge of the ecology of this micro-organism and may in the future help prevent infections both in fish and in humans.

Aeromonas↗

PubMed2002

Diffuse hyperplastic oncocytosis of the parotid gland.

Oncocytic tumours rarely affect the major salivary glands, accounting for less than 1% of all salivary-gland tumours. The World Health Organisation classification groups these tumours into three principal types: diffuse oncocytosis, focal adenomatous oncocytic hyperplasia and oncocytoma. Diffuse hyperplastic oncocytosis is the rarest lesion: only six cases have been previously reported in the literature. This condition of putative hyperplastic pathogenesis follows a benign course, whereas oncocytomas may recur after excision. No metastatic dissemination or recurrence of diffuse hyperplastic oncocytosis has been reported. We present and discuss a new case of diffuse hyperplastic oncocytosis of the parotid gland.

Biopsy, Needle↗

PubMed2002

Occurrence of extended-spectrum beta-lactamases in members of the family Enterobacteriaceae in Italy: implications for resistance to beta-lactams and other antimicrobial drugs.

An Italian nationwide survey was carried out to assess the prevalences and the antimicrobial susceptibilities of members of the family Enterobacteriaceae producing extended-spectrum beta-lactamases (ESBLs). Over a 6-month period, 8,015 isolates were obtained from hospitalized patients and screened for resistance to extended-spectrum cephalosporins and monobactams. On the basis of a synergistic effect between clavulanate and selected beta-lactams (ceftazidime, aztreonam, cefotaxime, cefepime, and ceftriaxone), 509 isolates were found to be ESBL positive (6.3%). Colony blot hybridization with bla(TEM) and bla(SHV) DNA probes allowed one to distinguish four different genotypes: TEM-positive, SHV-positive, TEM- and SHV-positive, and non-TEM, non-SHV ESBL types. MICs for each isolate (E-test) were obtained for widely used beta-lactams, combinations of beta-lactams with beta-lactamase inhibitors, aminoglycosides, and fluoroquinolones. Among ESBL-positive strains, Klebsiella pneumoniae, Proteus mirabilis, and Escherichia coli accounted for 73.6% of isolates. Overall, TEM-type ESBLs were more prevalent than SHV-type enzymes (234 versus 173), whereas the prevalence of strains producing both TEM- and SHV-type ESBLs was similar to that of isolates producing non-TEM, non-SHV enzymes (55 and 38, respectively). In vitro, all but one of the ESBL-producing isolates remained susceptible to imipenem. Susceptibility to other drugs varied: piperacillin-tazobactam, 91%; amoxicillin-clavulanic acid, 85%; cefoxitin, 78%; amikacin, 76%; ampicillin-sulbactam, 61%; ciprofloxacin, 58%; and gentamicin, 56%. Associated resistance to aminoglycosides and ciprofloxacin was observed most frequently among TEM-positive strains. Since therapeutic options for multiresistant Enterobacteriaceae are limited, combinations of beta-lactams and beta-lactamase inhibitors appear to represent an important alternative for treating infections caused by ESBL-producing ENTEROBACTERIACEAE:

Aminoglycosides↗

PubMed2002

Multicenter comparative evaluation of six commercial systems and the national committee for clinical laboratory standards m27-a broth microdilution method for fluconazole susceptibility testing of Candida species.

Fluconazole susceptibility among 800 clinical Candida isolates (60% C. albicans) and two control strains (C. krusei ATCC 6258 and C. parapsilosis ATCC 22019) was tested with the NCCLS M27-A method (gold standard) and six commercial products (Candifast, disk, Etest, Fungitest, Integral System Yeasts, and Sensititre YeastOne). Results were classified as susceptible, susceptible-dose dependent, or resistant using M27-A breakpoints or, for Fungitest, Integral System Yeasts, and Candifast, as susceptible, intermediate, or resistant, according to the manufacturers' instructions. Concordance with NCCLS M27-A results was analyzed with the chi(2) test. Intra- and interlaboratory reproducibility was also evaluated. NCCLS M27-A (90.1%), Etest (93.1%), Sensititre YeastOne (93.1%), disk (96.7%), Fungitest (92.6%), Integral System Yeasts (40.6%), and Candifast (6.0%) classified the indicated percentages of C. albicans isolates as susceptible. Among non-C. albicans strains, the percentages of susceptible isolates were as follows: NCCLS M27-A, 74.0%; Etest, 83.8%; Sensititre YeastOne, 64.1%; disk, 60.6%; Fungitest, 76.6%; Integral System Yeasts, 28.3%; and Candifast, 27.4%. All methods except Candifast and Integral System Yeasts showed good agreement with NCCLS M27-A results for both C albicans and non-C. albicans isolates. Intralaboratory reproducibility was excellent for NCCLS M27-A, Etest, Sensititre YeastOne, disk, and Fungitest (88 to 91%). Similar results emerged from the interlaboratory reproducibility evaluation. Our findings indicate that some commercial methods can be useful for fluconazole susceptibility testing of clinical Candida isolates. Those characterized by a lack of medium standardization and/or objective interpretative criteria should be avoided. Particular caution is necessary when testing is being done for clinical and epidemiological purposes.

Antifungal Agents↗

PubMed2002

Strain variation in Mediterranean and Red Sea Mycobacterium marinum isolates.

Four different PCR fingerprinting techniques were tested to distinguish possible strain variations in fourteen Mycobacterium marinum isolates, thirteen from Mediterranean and Red Sea fishes and one from a patient in Sardinia, Italy. PCR ribotyping and ERIC (enterobacterial repetitive consensus sequences)-PCR were found to be non-discriminative, whereas IS (insertion sequences)-PCR and GTG (GTG sequences repeats)-PCR could distinguish the clinical isolate from the piscine isolates, two Italian piscine isolates from all other isolates, but not the Greek isolates from the Israeli isolates. Our results indicate that GTG-PCR and IS-PCR have superior discriminative properties and are thus useful molecular tools for epidemiological studies of M. marinum.

Animals↗

PubMed2001

Glycopeptide resistance among coagulase-negative staphylococci that cause bacteremia: epidemiological and clinical findings from a case-control study.

A 1-year prospective case-control study (ratio of control patients to case patients, 3:1) was performed to assess the incidence, risk factors, and genotypic patterns of bacteremia caused by glycopeptide-resistant coagulase-negative staphylococci (CoNS) and their correlation with hospital glycopeptide use. Among 535 subjects with CoNS bacteremia, 20 subjects had a glycopeptide-resistant strain (19 strains were resistant to teicoplanin and 1 was resistant to both teicoplanin and vancomycin). The percentage of resistant isolates recovered in 1 year was 8% in intensive care units and 3% and 2% in medical and surgical wards, respectively. Genotypic analysis of resistant strains showed different patterns with a high degree of polymorphism. Use of glycopeptides in individual wards was not statistically associated with the percentage of resistance. Previous exposure to beta-lactams and glycopeptides, multiple hospitalization in the previous year, and concomitant pneumonia were significantly associated with the onset of glycopeptide-resistant CoNS bacteremia. Mortality rates were 25% among case patients and 18% among control patients, and they were significantly higher among patients who presented with concomitant pneumonia and a high Acute Physiology and Chronic Health Evaluation III score.

Aged↗

PubMed2001

Nonneutralizing human antibody fragments against hepatitis C virus E2 glycoprotein modulate neutralization of binding activity of human recombinant Fabs.

Evidence from clinical and experimental studies indicates that hepatitis C virus E2 (HCV/E2) glycoprotein is the major target of a putatively protective immune response. However, even in the presence of a vigorous production of anti-HCV/E2 antibodies, reinfection can occur. Dissection of the human immune response against HCV/E2 indicated that blocking of binding of HCV/E2 to target cells [neutralization of binding (NOB) activity] varies widely among antibody clones. Moreover, in vivo, simultaneous binding of antibodies to distinct epitopes can induce conformational changes and synergies that may be relevant to understanding the anti-HCV immune response. In this study, human recombinant Fabs were generated by affinity-selecting a phage display repertoire library with antibody-coated HCV/E2. These Fabs, which share the same complementarity-determining region DNA sequences, had higher affinity than other anti-HCV/E2 Fabs but showed no NOB activity even at the highest concentrations. Binding of Fabs to HCV/E2 caused conformational changes modifying Fab-binding patterns and reducing, with a negative synergistic effect, Fab-mediated NOB activity. These data suggest that some antibody clones have the potential to modify HCV/E2 conformation and that, in this state, binding of this glycoprotein to its cellular target is less prone to inhibition by some antibody clones. This can explain why high anti-HCV/E2 antibody titers do not directly correlate with protection from infection. Information on the interactions among different antibody clones can contribute to understanding virus-host interplay and developing more effective vaccines.

Amino Acid Sequence↗

PubMed2001

On the arithmetic classification of crystal structures.

An arithmetic criterion for the classification of crystal structures with $n$ points in their unit cell ('n-lattices') was described by Pitteri & Zanzotto [Acta Cryst. (1998), A54 359-373]. In this paper, a systematic analysis of monoatomic 2-lattices is given, showing that there exist 29 distinct arithmetic types of these structures, some of which share the same space groups. As all monoatomic 2-lattices are constituted by a single crystallographic orbit, these structures are also classified by the established criterion of Fischer & Koch [Koch & Fischer (1975). Acta Cryst. A31, 88-95; Fischer & Koch (1996). International Tables for Crystallography, Vol. A. Dordrecht: Kluwer] involving the lattice complexes. The two classifications are found to coincide in this simplest case. By examination of some examples taken from the allotropes of the elements, it is also shown how the arithmetic criterion can be used to classify more complex crystals, such as monoatomic 4-lattices. This gives a group-theoretical framework for distinguishing structures when the space-group classification fails to do so, and Fischer & Koch's criterion, as presented in the literature, may not be immediately applied.

Journal Article↗

PubMed2001

An original technique for bladder autoaugmentation with protective abdominal rectus muscle flaps: an experimental study in rats.

BACKGROUND: Bladder autoaugmentation uses partial detrusorectomy to create a diverticular bulge in the bladder mucosa. This technique has eliminated certain serious complications of cystoplasty with gastrointestinal tissues (e.g., fluid/electrolyte/acid-base imbalances, mucous hypersecretion), but the exposed mucosa is subject to fibrosis and, sometimes, to perforation, which can annul the benefits of surgery. METHODS: We have developed an original technique based on traditional autoaugmentation with protection of the herniated mucosa by split-thickness pedunculated rectus abdominis muscle flaps that are sutured to the incised margins of the detrusor. Preliminary testing was done on 30 adult Wistar rats. A control group of 15 rats underwent laparotomy alone. Bladder capacity was measured via suprapubic cystography before and after (4 weeks, 8 weeks, 1 year) surgery, just before sacrifice. Sections of the reconstructed bladder were examined histologically. RESULTS: Twenty-three bladder-augmented rats and 13 controls survived. In the experimental group, bladder capacity increased by 38% (mean). None of the rats experienced urinary retention, although one developed bladder stones. Histology revealed no pathologic changes (other than chronic inflammatory infiltrates at suture sites) in the mucosa, detrusor, or muscle flaps, which were all viable and well integrated by the fourth postoperative week. There were no signs of mucosal or muscle fibrosis. CONCLUSIONS: Preliminary results in a rat model suggest that this new technique can produce an enlarged bladder that is fully functional and less vulnerable to fibrotic retraction and rupture. Residual contractility in the muscle flaps might theoretically be exploited to facilitate paraphysiologic micturition.

Abdominal Muscles↗

PubMed2001

Changes in incidence and risk factors of Mycobacterium avium complex infections in patients with AIDS in the era of new antiretroviral therapies.

The aim of the study presented here was to determine the incidence, risk factors and prognostic indicators of Mycobacterium avium complex (MAC) infection in HIV-infected subjects prior to and after the introduction of highly active antiretroviral therapy (HAART). In the HAART era, the incidence of MAC infection decreased significantly from 3.7 to 0.9 per 100 person-years. Using logistic regression analysis, a high acute physiology and chronic health evaluation (APACHE) III score, a low number of CD4+ cells/ mm3 and a high level of HIV viremia were found to be independent predictors of the risk to develop MAC disease; however, a high APACHE III score was the only prognostic indicator associated with an unfavourable outcome of a disseminated MAC infection. These results indicate that MAC infections, although considerably less frequent in the HAART era, are still responsible for cases of severe disease.

AIDS-Related Opportunistic Infections↗

PubMed2001

In vitro susceptibility of Vibrio spp. isolated from the environment.

Bacteria of the genus Vibrio include harmless aquatic strains as well as strains capable of causing epidemics of cholera and human intestinal diseases. Some of these species may show resistance to different antibiotics including cefotaxime, tetracycline and chloramphenicol. The susceptibility to different antibiotics was tested using 40 Vibrio alginolyticus, eight V. parahaemolyticus and six V. vulnificus strains isolated in the coastal waters of Northern Sardinia (Italy). The frequency of resistance to beta-lactams was unexpectedly high. More than 80% of Vibrio isolates were resistant to ampicillin and 2.5% of V. alginolyticus were resistant to ceftazidime and cefotetan. Forty percent of V. alginolyticus and three V. vulnificus isolates gave a positive nitrocefin test. PCR was also performed using selected primers chosen for having common sequences of bla(TEM) and bla(SHV) genes.

Anti-Bacterial Agents↗