Biomedical subjects

R Filip

Publications and source records attributed to R Filip.

14 recordsLinked to original sources

PubMed2006

Squeezed-state purification with linear optics and feedforward.

A scheme for optimal and deterministic linear optical purification of mixed squeezed Gaussian states is proposed and experimentally demonstrated. The scheme requires only linear optical elements and homodyne detectors, and allows the balance between purification efficacy and squeezing degradation to be controlled. One particular choice of parameters gave a tenfold reduction of the thermal noise with a corresponding squeezing degradation of only 11%. We prove optimality of the protocol, and show that it can be used to enhance the performance of quantum informational protocols such as dense coding and entanglement generation.

Journal Article↗

PubMed2006

Distillation of squeezing from non-Gaussian quantum states.

We show that single copy distillation of squeezing from continuous variable non-Gaussian states is possible using linear optics and conditional homodyne detection. A specific non-Gaussian noise source, corresponding to a random linear displacement, is investigated experimentally. Conditioning the signal on a tap measurement, we observe probabilistic recovery of squeezing.

Journal Article↗

PubMed2006

Realization of a minimal disturbance quantum measurement.

We report the first experimental realization of an "optimal" quantum device able to perform a minimal disturbance measurement on polarization encoded qubits saturating the theoretical boundary established between the classical knowledge acquired of any input state, i.e., a "classical guess," and the fidelity of the same state after disturbance due to measurement. The device has been physically realized by means of a linear optical qubit manipulation, postselection measurement, and a classical feed-forward process.

Journal Article↗

PubMed2005

Separating the classical and quantum information via quantum cloning.

An application of quantum cloning to optimally interface a quantum system with a classical observer is presented; in particular, we describe a procedure to perform a minimal disturbance measurement on a single qubit by adopting a 1-->2 cloning machine followed by a generalized measurement on a single clone and the anticlone or on the two clones. Such a scheme can be applied to enhance the transmission fidelity over a lossy quantum channel.

Journal Article↗

PubMed2005

alpha-Ketoglutarate (AKG) absorption from pig intestine and plasma pharmacokinetics.

To study the absorption, metabolism and kinetics, the AKG (in different concentrations) was administered intravenously, intra-portally, orally and directly into the ileum or duodenum of pigs, chronically fitted with portal and jugular catheters and T-shaped cannula at the duodenum and ileum. Additionally, this study was conducted to determine the influence of low pH, Fe(2+) or/and SO on AKG gut absorption and conversely FeSO(4) and FeSO(4)/AKG on Fe(2+) gut absorption. It is concluded that AKG was significantly better absorbed from the upper small intestine than from the distal sections. Furthermore, low pH, Fe(2+) and/or SO ions enhanced AKG absorption. The AKG administered to the portal vein was rapidly eliminated from the blood (half-life less than 5 min). The short lifetime for AKG is probably dependent on quick metabolism in the enteorcyetes and liver. However, the prolonged half-life can be related to its low AKG blood concentration. The Fe(2+) concentrations in blood increased after FeSO(4) and FeSO(4)/AKG duodenal infusion. The implication of above observations is important for practical application of the AKG in animal and human nutrition as well in medicine.

Administration, Oral↗

PubMed2004

Experimental purification of single qubits.

We report the experimental realization of the purification protocol for single qubits sent through a depolarizing channel. The qubits are associated with polarization states of single photons and the protocol is achieved by means of passive linear optical elements. The present approach may represent a convenient alternative to the distillation and error correction protocols of quantum information.

Journal Article↗

PubMed2004

Molecular characterization of beta-lactam resistance of Salmonella isolates from pediatric patients in Romania.

The molecular characterization of 16 clinical isolates of Salmonella enterica (14 serotype Typhimurium and 2 serotype Kingston) obtained between January and June 1999 from feces of children hospitalized in Iasi, Romania were genotypically compared by pulse field gel electrophoresis of XbaI restricted bacterial DNA. The majority of the clinical isolates (12/16) belonged to cluster A and (4/16) to unrelated strains, correlating to the OMP profile. Two major different patterns of beta-lactamases were identified: the first with pI of 5.4, 8.2 in 6/16 strains and the second with pI of 5.4 in 5/16. The blaTEM beta-lactamase was identified in 14/16 of the clinical isolates and the blaSHV-5 gene in one strain. We concluded that extended spectrum beta-lactamase (ESBL) with pIs of 8.2 was the most frequent enzyme produced by serotype Typhimurium isolates which were related.

Base Sequence↗

PubMed2003

Researching on new species of "Mate": Ilex brevicuspis: phytochemical and pharmacology study.

BACKGROUND: Ilex paraguariensis St. Hilaire (Aquifoliaceae) ("Mate" or "Yerba mate") is one of the most commercialized plants of South America which grows naturally in NE Argentina, Uruguay, SE Brazil and E Paraguay, where it is also cultivated. It is used to prepare a tea-like beverage (infusions or decoctions) appreciated for its peculiar flavor, stimulation and nutritional properties. Ilex brevicuspis Reisseck grows in the same habitat and is widely used as a substitute or adulterant of Ilex paraguariensis. In a previous work, methylxanthines (caffeine, theobromine and theophylline) were not detected in it by HPLC. AIM OF THE STUDY: This study was undertaken in order to isolate, identify and quantify the polyphenolic compounds (caffeoyl derivatives and flavonoids) and to investigate some of the pharmacological activities of I. brevicuspis, related with the traditional use of the "Mate" (choleretic, intestinal propulsion and antioxidant activities). Acute toxicity was also investigated. METHODS: Decoctions, like extracts, were prepared in order to compare the results with preparations commonly used by the local people. For the phytochemical analysis, the extracts were analyzed by HPLC with a diode array detector. Choleretic and intestinal propulsion activities were assayed in rats. Sodium dehydrocholate (DHC) was used as a choleretic reference standard. Antioxidant activity was tested in liposomes that were oxidized by the free radical generator 2,2'-azobis [amidinopropane] chloride (AAPH). RESULTS: For the first time in I. brevicuspis the following compounds were isolated and quantified: A) caffeoyl derivative compounds (chlorogenic acid; caffeic acid; 3,4-dicaffeoylquinic acid; 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid. B) flavonoids (rutin, quercetin and kaempferol). Biological activity assays demonstrated that I. brevicuspis extracts produced a significant increase of bile flow (BF) in rats in the first 30 min period and in the percentage of BF increase accumulated at 120 min. It also produced an increase in the intestinal propulsion activity. Moreover, this species showed a high antioxidant activity. The acute toxicity test showed that Ilex brevicuspis did not produce any sign of toxicity at the analyzed doses. CONCLUSIONS: An Argentinean Ilex specie ( I. brevicuspis) has choleretic, intestinal propulsion, antioxidant activities and these results may lead to the potential development of a new "Yerba Mate" and/or phytopharmaceutical products, without central nervous system (CNS) stimulant activity.

Animals↗

PubMed2001

Phenolic compounds in seven South American Ilex species.

Ilex paraguariensis (common name: 'mate' or 'yerba mate') is used for the preparation of the most popular tea-like beverage of South America. Choleretic, hypocholesteremic, antioxidant, hepatoprotective and bitter taste properties of mate are attributed to the phenolic constituents of the leaves. I. paraguariensis has seven local congeneric substitutes or adulterants: I. brevicuspis; I. theezans; I. microdonta; I. dumosa var. dumosa; I. taubertiana; I. pseudobuxus; I. integerrima; and I. argentina. An HPLC method using UV with Photodiode Array Detector was developed for the identification and quantification of caffeoyl derivatives (caffeic acid, chlorogenic acid, 3,4-dicaffeoylquinic acid, 3,5-dicaffeoylquinic acid and 4,5-dicaffeoylquinic acid) and flavonoids (quercetin, rutin and kaempferol) in these species. I. paraguariensis showed a higher content of flavonoids and caffeoyl derivatives than the other assayed species.

Caffeic Acids↗

PubMed2001

Choleretic effect and intestinal propulsion of 'mate' (Ilex paraguariensis) and its substitutes or adulterants.

'Mate' or 'Yerba mate' (Ilex paraguariensis, Aquifoliaceae) is a tonic and stimulant beverage widely used in South America. It is also traditionally used in gastrointestinal disorders as eupeptic and choleretic agent. Accordingly, the effect of decoctions of the leaves of I. paraguariensis and three of its substitutes or adulterants (Ilex brevicuspis, Ilex argentina and Ilex theezans) on bile flow (BF) and intestinal propulsion were investigated. I. paraguariensis and I. brevicuspis induced an increase in BF, while the latter also enhanced intestinal transit. In contrast, neither I. argentina nor I. theezans exerted any effect on BF or intestinal propulsion. These results suggest that the therapeutic properties of I. paraguariensis will be affected when at least an adulterant is present in the final commercial product of Yerba mate.

Animals↗

PubMedDate not supplied

Resistance mechanism for a number of non-typhoidic Salmonella strains isolated in Iaşi, Romania.

The aim of this study was to find a possible explanation for the resistance pattern of the selected strains and to evaluate the impact in case of isolating such strains. During the period February-March 1998, in the Pediatric Hospital "Sf. Maria" from Iasi, Romania, 12 non-typhoidic Salmonella strains, non-duplicates were isolated from stools of newborns and, in one case, from mother as well. Identification was done by standard methods, and sensitivity testing by disk diffusion method, against the following antimicrobials: Ampicillin (A), Amoxycilin/Clavulanic Acid (AMC), Tetracycline (T), Streptomycin (S), Cloramphenicol (C), Nalidixic Acid (NA), Ciprofloxacin (CIP), Cephalotin (KF), Cefuroxime (CXM), Ceftriaxone (CRO), Cefotaxime (CTX), Ceftazidime (CAZ), Aztreonam (AZT), Imipenem (IPM), Amikacin (AK). All strains showed resistance to: A, AMC, T, S, C, NA, CRO, CAZ, CXM, CTX, KF except one strain, CTX and CRO sensitive. The possible explanation is the production of an extended-spectrum beta-lactamase (ESbLA), detected by microbiological methods (Masuda and clover-leaf). Resistance transfer was realised by using the previously described method. In conjugation experiments we have obtained only one transconjugant, identified as E. coli, that has acquired all resistance determinants. This report highlights on the isolation of multiresistant non-typhoidic Salmonella strains in hospitalised patients without previous antibiotic treatment and possibility of detecting such strains by being aware of the correlation: resistance phenotype-resistance mechanism.

Adult↗

PubMedDate not supplied

Sensitivity of Enterobacteriaceae strains to the third generation cephalosporins.

The aim of this study was to evaluate the in vitro activity of cefotaxime, ceftriaxone, ceftazidime, ceftibuten and aztreonam against the clinical isolates of Enterobacteriaceae. MICROORGANISMS: A total of 973 enterobacteria isolated from clinical material (urine and faeces) were tested. Strains were collected during 1996-1998 period, in some centers of Eastern Romania. SENSITIVITY STUDY: MICs were performed using the agar dilution method following standardized techniques (NCCLS, 1994). Stock solutions of antibacterial agents were prepared from their respective powder forms, in concentrations ranging from 0.03 to 128 mg/ml. Our results show a good activity of the tested antimicrobials on Escherichia coli, Shigella spp and Klebsiella spp tested, and reveal a particular behaviour for Salmonella spp, characterized by a heterogenous susceptibility. In conclusion, cefotaxime, ceftriaxone, ceftazidime, ceftibuten and aztreonam were active at low concentrations against tested isolates. Against Salmonella spp, these agents were less active: percent of resistant strains by beta-lactamase production was significant.

Cephalosporins↗

PubMedDate not supplied

Study of outer membrane proteins (OMPS) and their role in co-modulation of resistance in non typhoidic Salmonella strains isolated in Iaşi.

OBJECTIVES: To characterize the OMP profile and to study the possible interference with other resistance determinants. MATERIAL AND METHODS: 16 non-typhoidic Salmonella strains, isolated in 1999 from stools of pediatric patients, were selected according to their resistance phenotype: resistance to Ampicillin (AMP), Amoxycillin/Clavulanic Acid (AMC), and third generation cephalosporins: Ceftriaxone (CRO) and Ceftazidime (CAZ). Identification and sensitivity testing were done by DADE MicroScan System. beta-Lactamases were characterized by isoelectric focusing (IEF) with preformed minigelss. OMPs were studied on membrane preparations on SDS-urea gels. RESULTS: Isoelectric points: Majority of the isolates had the association 5.4 +/- 7.6 (3/16) or 5.4 + 8.2 (6/16). The second beta-lactamase has the capacity to hydrolyse CAZ. We found three different patterns of OMPs: I: 30, 29 and 25 kDa; II: 30, 26 and 24 kDa; III: 30 and 25 kDa. We couldn't find any correlation between the OMPs profile and resistance phenotype, showing that the beta-lactamase production is the only resistant determinant. CONCLUSIONS: The study shows the high frequency of extended-spectrum beta-lactamases (ES beta LA) amongst the non-typhoidic Salmonella; association of TEM type and ES beta LA enzymes diminishes considerably the therapeutic resources: inhibitor associated combinations are non effective. In non-typhoidic Salmonella, porins seems to have no influence in co-modulation of resistance.

Anti-Bacterial Agents↗

PubMedDate not supplied

Investigations on the presence of viral and chlamydial antigens in cells exfoliated in the vagina of women with common and malignant gynecopathies.

A high proportion of parainfluenza, herpes, adenovirus and chlamydial antigens (10.7-36%) was detected by indirect immunofluorescence in cells exfoliated in the vagina of women with genital neoplasia and with uterine cervix ectopia and dysplasia. Much lower proportions of the same antigens were found in patients with common gynecopathies or recurrent genital herpes and in pregnant women. The possible relationships between chronic virus infections and genital neoplasia in women are discussed.

Antigens, Bacterial↗