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Biomedical subjects

F Villani

Publications and source records attributed to F Villani.

At least 37 records · Page 2Linked to original sources
PubMed2001

Differential viable count of mixed starter cultures of lactic acid bacteria in doughs by using modified Chalmers medium.

The modified Chalmers medium appeared as quite suitable for counting a mixed population consisting of different species of lactic acid bacteria used as starter in breadmaking. Selected strains of Lactobacillus plantarum, Leuconostoc mesenteroides subsp. mesenteroides, Lactobacillus sanfranciscensis, Enterococcus faecalis together with Saccharomyces cerevisiae could be easily differentiated and counted with an acceptable recovery in comparison with reference media.

Agar↗
PubMed2001

Detection and characterization of a bacteriocin, garviecin L1-5, produced by Lactococcus garvieae isolated from raw cow's milk.

AIMS: The identification of a bacteriocin-producing lactococcal strain isolated from raw cow's milk is reported, along with production conditions, physical and chemical properties, and mode of action of the bacteriocin. METHODS AND RESULTS: On the basis of resistance to clindamycin, species-specific PCR and amplification of the 16S-23S rDNA spacer region, the strain was identified as Lactococcus garvieae. Its bacteriocin, designated garviecin L1-5, was bactericidal against closely related species and strains of species from different genera, including Listeria monocytogenes and Clostridium spp. Garviecin L1-5 was shown to be proteinaceous by protease inactivation and was unaffected by heat treatments, also at low pH values. When amplifying known lactococcal bacteriocin genes using DNA from strain L1-5 as template, no amplification products were observed on the agarose gel. The molecular weight of garviecin L1-5 was about 2.5 kDa. As far as is known, no bacteriocins have been detected from Lactococcus garvieae. CONCLUSION: The general properties of garviecin L1-5 are characteristic of the low-molecular-weight bactericidal peptide group. SIGNIFICANCE AND IMPACT OF THE STUDY: The survey of micro-organisms for novel antimicrobial substances provided valuable information on their physiology, ecology and practical application.

Animals↗
PubMed2001

Comparison of statistical methods for identification of Streptococcus thermophilus, Enterococcus faecalis, and Enterococcus faecium from randomly amplified polymorphic DNA patterns.

Thermophilic streptococci play an important role in the manufacture of many European cheeses, and a rapid and reliable method for their identification is needed. Randomly amplified polymorphic DNA (RAPD) PCR (RAPD-PCR) with two different primers coupled to hierarchical cluster analysis has proven to be a powerful tool for the classification and typing of Streptococcus thermophilus, Enterococcus faecium, and Enterococcus faecalis (G. Moschetti, G. Blaiotta, M. Aponte, P. Catzeddu, F. Villani, P. Deiana, and S. Coppola, J. Appl. Microbiol. 85:25-36, 1998). In order to develop a fast and inexpensive method for the identification of thermophilic streptococci, RAPD-PCR patterns were generated with a single primer (XD9), and the results were analyzed using artificial neural networks (Multilayer Perceptron, Radial Basis Function network, and Bayesian network) and multivariate statistical techniques (cluster analysis, linear discriminant analysis, and classification trees). Cluster analysis allowed the identification of S. thermophilus but not of enterococci. A Bayesian network proved to be more effective than a Multilayer Perceptron or a Radial Basis Function network for the identification of S. thermophilus, E. faecium, and E. faecalis using simplified RAPD-PCR patterns (obtained by summing the bands in selected areas of the patterns). The Bayesian network also significantly outperformed two multivariate statistical techniques (linear discriminant analysis and classification trees) and proved to be less sensitive to the size of the training set and more robust in the response to patterns belonging to unknown species.

Bayes Theorem↗
PubMed2000

MS-2 fibrosarcoma characterization by laser induced autofluorescence.

BACKGROUND AND OBJECTIVE: MS-2 fibrosarcoma implanted in BALB-CDF1 mice was investigated by frequency and time domain measurements of the autofluorescence (AF) radiation emitted upon excitation by a N(2) laser beam (337.1 nm). STUDY DESIGN/MATERIALS AND METHODS: AF spectra were obtained by using a spectrograph, a multichannel plate and an optical multichannel analyzer for the steady state detection. Time-resolved spectra were performed by means of a monochromator, a photomultiplier, and a digital signal analyzer. RESULTS: Spectral measurements show that the autofluorescence intensity of pathologic tissue is lower than that of healthy one in the 400- to 500- spectral region. In the same spectral range, we found the fluorescence decay to be the sum of a fast and a slow component. The lifetime of the fast component of tumoral tissue is significantly lower than that of healthy samples. CONCLUSION: Frequency and time domain measurements used in combination show that MS2-fibrosarcoma is characterized by the probable presence of the free form of NADH.

Animals↗
PubMed2000

Hypericin photosensitization of tumor and metastatic cell lines of human prostate.

We have investigated the photoactivating effect of hypericin on two cancer cell lines: PC-3, a prostatic adenocarcinoma non-responsive to androgen therapy and LNCaP, a lymphonodal metastasis of prostate carcinoma responsive to androgen therapy. The two cell lines are incubated for 24 h with hypericin at concentrations ranging from 0.001 to 0.3 microg/ml in cell culture medium. The cells are irradiated at 599 nm (fluence = 11 J/cm2) using a dye laser pumped by an argon laser. Hypericin exerts phototoxic effects on both cell lines, while it does not produce toxic effects in the absence of irradiation. These results suggest that photodynamic therapy (PDT) with hypericin could be an alternative approach to the treatment of prostatic tumors, and could be beneficial in tumors that are non-responsive to androgen therapy.

Adenocarcinoma↗
PubMed2000

Chloroplast DNA polymorphism reveals little geographical structure in Castanea sativa Mill. (Fagaceae) throughout southern European countries.

The distribution of haplotypic diversity of 38 European chestnut (Castanea sativa Mill.) populations was investigated by PCR/RFLP analysis of regions of the chloroplast and mitochondrial genomes in order to shed light on the history of this heavily managed species. The rapid expansion of chestnut starting from 3000 years ago is strongly related to human activities such as agricultural practice. This demonstrates the importance of human impact, which lasted some thousands of years, on the present-day distribution of the species. No polymorphism was detected for the single mitochondrial analysed region, while a total of 11 different chloroplast (cp) haplotypes were scored. The distribution of the cpDNA haplotypes revealed low geographical structure of the genetic diversity. The value of population subdivision, as measured by GSTc, is strikingly lower than in the other species of the family Fagaceae investigated. The actual distribution of haplotypic diversity may be explained by the strong human impact on this species, particularly during the Roman civilization of the continent, and to the long period of cultivation experienced during the last thousand years.

Agriculture↗
PubMed2000

Conditions for conjugative transposon transfer in Lactococcus lactis.

Three different techniques for bacterial mating were applied to wild type and culture collection strains of Lactococcus lactis harbouring transposons: direct plate conjugation, filter mating and mating on milk agar. Efficiencies and frequencies of transfer were compared. Transconjugants were characterized by marker properties and molecular assays. Transposon-coded Suc+ Nis+ phenotype as well as Suc+ Bac+ Nis- phenotype were transferred with frequencies ranging between 10-9 and 10-6. Milk agar plate mating was the best technique for obtaining gene transfer events involving wild type lactococci.

Conjugation, Genetic↗
PubMed2000

Antibiotic resistance of coagulase-negative staphylococci isolated from artisanal Naples-type salami.

In the present paper 42 isolates from Italian salami were specified as Staphylococcus xylosus (30), Staph. capitis (1), Staph. saprophyticus (1), Staph. hominis (1), Staph. simulans (1), Staph. cohnii (1) and as Staph. spp. (7). These strains were coagulase-negative and were examined for resistance/sensitivity against 25 antibiotics including beta-lactams (7), macrolides (3), amynoglicosides (5), glycopeptides, lincosamides (4) and novobiocin, fusidic acid, chloramphenicol, rifampicin, tetracycline, minocycline. More than 64% of the strains were resistant to lincomycin, penicillin G, amoxicillin, fusidic acid and novobiocin. All the strains were multiresistant and displayed at least three resistances. Over 75% had a multiple antibiotic resistance (MAR) index between 0.2 and 0.5.

Animals↗
PubMed2000

Late pulmonary effects in favorable stage I and IIA Hodgkin's disease treated with radiotherapy alone.

Radiotherapy (RT) in patients with favorable-stage Hodgkin's disease can induce clinical and subclinical evidence of pulmonary damage lasting over the years. In this study, we monitored 36 patients with stage IA-IIA Hodgkin's disease treated with subtotal nodal RT. The planned dose of RT was 40 Gy to 44 Gy to the involved areas and 36 Gy to the adjacent uninvolved areas. Pulmonary function was evaluated by chest radiograph, spirometric parameters, arterial blood gas analysis, and single-breath CO transfer factor (DLCO). The tests were performed before and at the end of irradiation, and during the follow-up 1 and 3 to 5 years after the treatment. At the end of RT, we found a significant decrease of total lung capacity, vital capacity, forced expiratory volume in 1 second, residual volume, and DLCO. Spirometric parameters improved during the follow-up period, whereas the decline of DLCO (-6.4%) was persistent. No correlation was found between mantle RT dose and DLCO changes. Four patients showed a decline of DLCO of >20% from pretreatment values but only one was symptomatic. Our study confirms that RT induces a pulmonary-restrictive disease at a subclinical level that seems to be reversible in the majority of patients.

Adolescent↗
PubMed2000

Specific detection of Leuconostoc mesenteroides subsp. mesenteroides with DNA primers identified by randomly amplified polymorphic DNA analysis.

Randomly amplified polymorphic DNA analysis using primer 239 (5' CTGAAGCGGA 3') was performed to characterize Leuconostoc sp. strains. All the strains of Leuconostoc mesenteroides subsp. mesenteroides (with the exception of two strains), two strains formerly identified as L. gelidum, and one strain of Leuconostoc showed a common band at about 1.1 kb. This DNA fragment was cloned and sequenced in order to verify its suitability for identifying L. mesenteroides subsp. mesenteroides strains.

DNA Primers↗
PubMed1999

Spray-drying of bacteriocin-producing lactic acid bacteria.

Cell survival, cellular damage, and antagonistic activity were investigated after spray-drying of four bacteriocin-producing strains of lactic acid bacteria: Lactococcus lactis subsp. lactis 140, isolated from natural whey culture and producing a narrow-inhibitory spectrum bacteriocin); L. lactis subsp. lactis G35, isolated from pizza dough and producing nisin; Lactobacillus curvatus 32Y and Lactobacillus sp. 8Z, isolated from dry sausages. Trials were performed with bacteria suspended in skimmed milk or directly grown in whey. Three air temperatures at the inlet of the drier (160, 180, and 200 degrees C) and three flow rates (10, 13, and 17 ml/min) were assayed. Cell viability and bacteriocin activity of the dried materials were determined immediately after the process and after 5, 15, 30, and 60 days of storage at 4 degrees C. There was no significant difference between the two feeding suspensions in cell survival, always decreasing with the increase of inlet-air temperature. No loss of bacteriocin activity was detected in reconstituted powders, nor was any loss of ability to produce bacteriocin found after drying. Investigations of sensitivity to NaCl revealed only temporary damage to dried bacteria. During storage for 2 months at 4 degrees C, all samples, but mainly the lactococcal strains, displayed a gradual decrease in cell survival. Bacteriocin activity remained at the same level, allowing powders to be considered as effective biopreservatives.

Aerosols↗
PubMed1998

Utility of multimodal evoked potential study and electroencephalography in mitochondrial encephalomyopathy.

We performed electroencephalography (EEG) and multimodal evoked potential (EP) studies in 16 patients with various forms of mitochondrial encephalomyopathy (ME). The electrophysiological investigations revealed signs of involvement of the peripheral and central nervous system (CNS) in 14 patients, with a high incidence of visual-EP (VEP) alterations, indicative of visual pathway vulnerability in mitochondrial diseases. No specific pattern of abnormalities emerged and, in particular, clinical and laboratory findings did not correlate with each other. EP (particularly VEP and electroretinogram) investigations should be part of the diagnostic work-up of patients with mitochondrial disorders in order to better characterize the clinical picture, disclose involvement of specific sensory systems of the CNS, and assess patients with atypical clinical presentations.

Adult↗
PubMed1998

Random amplified polymorphic DNA and amplified ribosomal DNA spacer polymorphism: powerful methods to differentiate Streptococcus thermophilus strains.

Streptococci from different collections and dairy materials were characterized by conventional and molecular methods. After amplification of the 16S-23S rDNA spacer region, all the strains referable to the genus Streptococcus exhibited a single polymerase chain reaction (PCR) product, allowing their differentiation from enterococci. Cleaving this PCR product with Hae III, two different restriction patterns could be observed, allowing Streptococcus salivarius DSM 20560T, Strep. thermophilus NCDO 822 and two strains of Streptococcus spp. to be gathered in one group and all the other strains in another. In order to achieve strain typing, all the cultures were investigated by random amplified polymorphic DNA (RAPD)-PCR analysis employing two selected primers. The results were treated by cluster analysis, appearing significantly consistent with both the taxonomic position and the origin of the strains. Pulsed-field gel electrophoresis (PFGE) of Sma I digests of the genomic DNA from 11 representative strains with decreasing levels of RAPD similarity allowed their diversity to be confirmed, even though RAPD-PCR proved to be less discriminating than PFGE analysis. The results are discussed with reference to the capability of the analytical procedures used to aid both identification and strain typing of streptococci, as well as the taxonomic structure of the species Strep. thermophilus.

Bacterial Typing Techniques↗
PubMed1998

Clinical and molecular findings in the first identified Italian family with dentatorubral-pallidoluysian atrophy.

OBJECTIVES: Dentatorubral-pallidoluysian atrophy (DRPLA) is a rare autosomal dominant neurodegenerative disorder mostly observed in Japan, rarely reported in American and North European populations. The aim of this study is to characterize the clinical and molecular features of the first identified Italian DRPLA family. PATIENTS AND METHODS: We describe a 33-year-old female presenting with ataxia, intellectual decline, epilepsy, and choreoathetosis with an adult age onset. Genomic DNA was isolated from peripheral blood lymphocytes of the patient and of her healthy family members following standard procedures. Molecular tests were performed including genetic analysis for SCA1, 2, and 3 (spinocerebellar ataxias), Huntington's disease (HD) and DRPLA, due to a possible overlapping in clinical presentation. RESULTS: Molecular analysis revealed in our patient the presence of a pathological CAG expansion within the DRPLA gene. We have also documented the presence of a smaller CAG expansion in her apparently healthy brother, excluding the possibility of a de novo mutation. CONCLUSION: We conclude that both siblings may have inherited the molecular lesion from their deceased father, the mother being normal at molecular evaluation. Our kindred and a previously reported family from the island of Malta suggest that hereditary DRPLA may also be present in the Mediterranean area.

Adult↗
PubMed1998

Effect of dietary supplementation with polyunsaturated fatty acids on bronchial hyperreactivity in subjects with seasonal asthma.

Dietary supplementation with omega-3 essential fatty acids results in the production of uniqe 5-lipoxygenase and cyclooxygenase products which are biologically less active and may inhibit the production, or actions, of the eicosanoids produced when arachidonic acid is the substrate for 5-lipoxygenase and cyclooxygenase, rather than omega-3 essential fatty acids. Since airway inflammation may play a central role in the pathophysiology of asthma, we studied the effect of omega-3 essential fatty acids on bronchial responsiveness in 7 atopic patients suffering from seasonal asthma due to airborne allergens, and positive to intracutaneous skin reaction to two or more allergens. Bronchial responsiveness to ultrasonically nebulized distilled water (UNDW) was determined 30 days from the initial ingestion of 3 g/day of omega-3 essential fatty acids and 30 days after stopping dietary supplementation. Flow volume curves and Raw were recorded before the provocation test, at the end of inhalation, and at 10-, 20-, 30- and 60-min intervals. The maximum fall in forced expiratory volume in 1 s (FEV1) and the maximum increase in airway resistance (Raw) were chosen as the main outcome parameters. After 30 days of dietary supplementation, bronchial responsiveness to UNDW was significantly improved (in fact maximum fall in FEV1 was -11% vs. -28% before treatment, and maximum increase in Raw was +37% vs. +265% before treatment). The challenge test repeated 30 days after stopping dietary supplementation was the same as that recorded before treatment. The present data strongly suggest the hypothesis that dietary supplementation with omega-3 essential fatty acids could decrease bronchial hyperreactivity in atopic patients.

Adult↗
PubMed1997

In vitro photo-activation of newly synthesized chlorin derivatives with red-light-emitting diodes.

We investigated the in vitro photo-activation properties of two chlorin derivatives, i.e. 8-cis-heptylchlorin dicarboxylic acid and 3-trans-heptylchlorin bisamidoglucose derivative, which exhibit lipophilic properties similar to those of the active fractions of Photofrin II, on a normal epithelial cell line (FRTL-5). We used as an irradiation source an array of diodes emitting red light (lambda = 675 nm), which produced a fluence of 7mW cm-2 on the cells. We found that photo-activation with chlorin derivatives in the concentration range 1-100 ng ml-1 greatly enhanced the mortality of the irradiated cells (energy density, 0.25 J cm-2) with respect to the control cells kept in the dark. This response is immediate and appears to be an "all or none' effect. Taking into account that compounds exhibit a strong absorbance peak in the long wavelength region of visible light where tissues are relatively transparent, our results suggest that chlorins can be considered to be good candidates for application in photodynamic therapy.

Animals↗