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Biomedical subjects

A Paris

Publications and source records attributed to A Paris.

At least 19 recordsLinked to original sources
PubMed2002

A high statistics measurement of the Lambda(+)(c) lifetime.

A high statistics measurement of the Lambda(+)(c) lifetime from the Fermilab fixed-target FOCUS photoproduction experiment is presented. We describe the analysis technique with particular attention to the determination of the systematic uncertainty. The measured value of 204.6 +/- 3.4 (stat) +/- 2.5 (syst) fs from 8034 +/- 122 Lambda(+)(c)-->pK(-)pi(+) decays represents a significant improvement over the present world average.

Journal Article↗
PubMed2002

Search for CP violation in the decays D+--> K(S)pi+ and D+-->K(S)K+.

A high-statistics sample of photoproduced charm from the FOCUS experiment has been used to search for direct CP violation in the decay rates for D+-->K(S)pi+ and D+-->K(S)K+. We have measured the following asymmetry parameters relative to D+-->K-pi+pi+: A(CP)(K(S)pi+) = (-1.6+/-1.5+/-0.9)%, A(CP)(K(S)K+) = (+6.9+/-6.0+/-1.5)%, and A(CP)(K(S)K+) = (+7.1+/-6.1+/-1.2)% relative to D+-->K(S)pi+. We have also measured the relative branching ratios and found Gamma(D+-->K(0)pi+)/Gamma(D+-->K-pi+pi+) = (30.60+/-0.46+/-0.32)%, Gamma(D+-->K(0)K+)/Gamma(D+-->K-pi+pi+) = (6.04+/-0.35+/-0.30)%, and Gamma(D+-->K(0)K+)/Gamma(D+-->K(0)pi+) = (19.96+/-1.19+/-0.96)%.

Journal Article↗
PubMed2002

[Inflammatory reaction and infection in severe burns].

Major burn injury is a lesion where the inflammatory reaction is exported to the whole body. After a short time of hemodynamic changes, this inflammation is kept by necrotic tissues, persistence of an opened wound, and by the pulmonary and gut reactions. When infection starts, it becomes difficult to distinguish its symptoms among the inflammatory signals. The main point of the care of burn patient consists in trying to control this reaction and the immuno-depression it leads to: early excision and grafts, early enteral nutrition, perfect nursing care. There is no specific medical treatment of this state. The antibiotic use must be well weighed up. Infection is often the trigger of the multiple organ dysfunction which is the way the burn patient dies but is not mandatory.

Burns↗
PubMed2001

Measurement of the branching ratios of D(+) and D(+)(s) hadronic decays to four-body final states containing a K(S).

We have studied hadronic four-body decays of D(+) and D(+)(s) mesons with a K(S) in the final state using data recorded during the 1996-1997 fixed-target run of the Fermilab high energy photoproduction experiment FOCUS. We report a new branching ratio measurement of gamma(D(+)-->K(S)K-pi(+)pi(+))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0768+/-0.0041+/-0.0032. We make the first observation of three new decay modes with branching ratios gamma(D(+)-->K(S)K+pi(+)pi(-))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0562+/-0.0039+/-0.0040, gamma(D(+)-->K(S)K+K-pi(+))/gamma(D(+)-->K(S)pi(+)pi(+)pi(-)) = 0.0077+/-0.0015+/-0.0009, and gamma(D(+)(s)-->K(S)K+pi(+)pi(-))/gamma(D(+)(s)-->K(S)K-pi(+)pi(+)) = 0.586+/-0.052+/-0.043, where in each case the first error is statistical and the second error is systematic.

Journal Article↗
PubMed2001

Study of the decay D0 --> K+pi-.

Using a large sample of photoproduced charm mesons from the FOCUS experiment at Fermilab (FNAL-E831), we observe the decay D0-->K+pi- with a signal yield of 149+/-31 events compared to a similarly cut sample consisting of 36 760+/-195 D0-->K-pi+ events. We use the observed ratio of D0-->K+pi- to D0-->K-pi+ (0.404+/-0.085+/-0.025)% to obtain a relationship between the D0 mixing and doubly Cabibbo suppressed decay parameters.

Journal Article↗
PubMed2001

A high affinity acceptor for phospholipase A2 with neurotoxic activity is a calmodulin.

One of the high affinity binding proteins for ammodytoxin C, a snake venom presynaptically neurotoxic phospholipase A(2), has been purified from porcine cerebral cortex and characterized. After extraction from the membranes, the toxin-binding protein was isolated in a homogenous form using wheat germ lectin-Sepharose, Q-Sepharose, and ammodytoxin-CH-Sepharose chromatography. The specific binding of (125)I-ammodytoxin C to the isolated acceptor was inhibited to different extents by some neurotoxic phospholipases A(2), ammodytoxins, bee venom phospholipase A(2), agkistrodotoxin, and crotoxin; but not by nontoxic phospholipases A(2), ammodytin I(2), porcine pancreatic phospholipase A(2), and human type IIA phospholipase A(2); suggesting the significance of the acceptor in the mechanism of phospholipase A(2) neurotoxicity. The isolated acceptor was identified as calmodulin by tandem mass spectrometry. Since calmodulin is generally considered as an intracellular protein, the identity of this acceptor supports the view that secretory phospholipase A(2) neurotoxins have to be internalized to exert their toxic effect. Moreover, since ammodytoxin is known to block synaptic transmission, its interaction with calmodulin as an acceptor may constitute a valuable probe for further investigation of the role of the latter in this Ca(2+)-regulated process.

Amino Acid Sequence↗
PubMed2001

[Difficult reintubation during a Fantoni's tracheostomy resolved using a laryngeal mask].

We report the failure of a reintubation under direct laryngoscopy, during a percutaneous tracheostomy by Fantoni method. After the accidental per-procedural extubation and in front of an unpredicted difficult conventional endotracheal intubation, a laryngeal mask was used as an airway intubator conduit for the blind passage of the set's ventilation tube. This ventilation tube is a 40 cm long, 4 mm internal diameter special catheter with low pressure cuff, included into the TLT kit. The end of the procedure was uneventful.

Coronary Artery Bypass↗
PubMed2001

Uterotrophic effect of a saturated fatty acid 17-ester of estradiol-17beta administered orally to juvenile rats.

In comparison to estradiol-17beta, the naturally synthesized estradiol-17beta-17-fatty acid esters are potent estrogens when administered subcutaneously. A lipophilic character of estradiol-17-esters could partially protect them from metabolic inactivation. In order to compare their relative estrogenic potency when administered orally, the uterotrophic response to different dosages (0, 2.5, 25, 250 and 2500 nmol/kg BW/day) of estradiol-17beta and estradiol-17beta-17-stearate was assessed in juvenile Sprague-Dawley female rats. Estrogens were administered by oral gavage once a day for 6 days. On the 7th day uterus and vagina were dissected, weighed, and examined microscopically. At 2.5 and 25 nmol/kg BW/day, no difference was detected in the uterus weight compared to control animals which received the vehicle alone (corn oil). At 250 nmol/kg BW/day, the uterotrophic response was maximal in estradiol-17beta-17-stearate-treated animals (x2.40-2.70), whereas it was moderate in estradiol-17beta-treated rats (x1.86) at the same dosage. This differential weight gain effect of estradiol-17beta-17-stearate was correlated with typical microscopic changes in uterus and vagina. The results are in favour of a stronger estrogenic effect of orally given lipoidal estrogens compared to estradiol-17beta. This could be explained by a slower but sustained absorption of estradiol-17beta released from estradiol-17beta-17-stearate by esterases and/or by a facilitated transfer of esters in the lymphatic circulation.

Administration, Oral↗
PubMed2001

Genotypic and phenotypic heterogeneity of Streptococcus thermophilus strains isolated from dairy products.

AIMS: Forty strains of Streptococcus thermophilus isolated from dairy products were identified and typed by a polyphasic approach which included phenotypic and genotypic criteria. METHODS AND RESULTS: Strains were identified by sugar fermentation pattern and species-specific PCR. Phenotypic diversity was evaluated by a chemometric model taking into account some biochemical characteristics (e.g. acidifying and peptidase activities) of technological interest. Genotypic diversity was evidenced by PCR fingerprinting. The overall phenotypic and genotypic information was elaborated on a multivariate statistical basis by principal components analysis and cluster analysis, respectively. When acidifying and peptidase activities were considered, PCA indicated that most of the strains isolated from Pecorino Toscano cheese were separable from the others. Similarly, most of the starter culture strains tended to separate from the cheese isolates. CONCLUSIONS: A wide strain heterogeneity among Strep. thermophilus strains isolated from dairy products was observed. SIGNIFICANCE AND IMPACT OF THE STUDY: A computerized analysis of genotypic and phenotypic information could be applied successfully to differentiate and characterize reliably and rapidly isolates occurring in different dairy products and to comprehend the technological role of specific Strep. thermophilus strains in dairy technology.

Animals↗
PubMed2001

Assessment of estradiol and its metabolites in meat.

Most studies related to research on steroids in main edible tissues (muscle, liver or kidney) have focused on measurement of parent or major metabolite residues. In order to evaluate the estradiol content in bovine edible tissues, a multi-step extraction procedure was developed in conjunction with parallel metabolism studies of [14C]-17beta-estradiol in cattle (1-2). Various classes of free estradiol and conjugates were separated: estradiol -17beta and -17alpha, estradiol-17-fatty acid esters, estradiol 17-glycoside, estradiol 3-glucuronide, estradiol-17-glycoside and 3- glucuronide (diconjugates) were separated. No sulphates conjugated forms have been found at the detection level of the method. The quantification was realized by calibration with deuterated 17beta -estradiol -d3 standard and was validated at the ng x kg(-1) (ppt) level. Muscle, liver, kidney and fat samples from control or Revalor S single (licensed implantation) or multi-implanted steers have been assayed. The results show a wide variation between animals, but both the highest value and the mean of total estradiol content in each group proportionally increase from untreated to multi-implanted animals. In accordance with international rules, a calculation of the daily food supply of estradiol by such edible tissues in comparison with the acceptable daily intake was performed.

Adipose Tissue↗
PubMed2001

[Heart rate variability in anesthesia].

Measurement of heart rate variability (HRV) in the perioperative period is not yet part of routine monitoring. Because of a lack of standardization, comparison of results of different investigations is difficult. Caution is needed in interpreting data of HRV measurements because of the complexity of autonomic control of the cardiovascular system. Moreover, confounding effects of multiple factors influencing HRV in the perioperative setting make interpretation of data difficult and limit this methodology, for example, as a depth-of-anaesthesia monitor. HRV reflects the response of the heart to a variety of influences. None of the parameters obtained, however, elucidates directly the mechanism or site of action of an anaesthetic drug. Knowledge of the pathophysiology underlying HRV is critical in order to understand the state of the autonomic nervous system and its relevance for patient management. Nevertheless, previous studies show that HRV can provide information about sympathetic and parasympathetic influences affecting the cardiovascular system in the perioperative period. Thus, HRV seems to be a useful tool for preoperative cardiovascular risk stratification. Of major concern in this context is the quality of the recording of the electrocardiogram when assessing HRV. Because of the ongoing progress in monitoring with regard to acquisition and computer-based analysis of HRV data, it seems at least possible to measure HRV routinely in the perioperative setting. However, the need for standardization requires large prospective and standardized trials. Depending on the results, the clinical relevance of HRV as a relatively simple and non-invasive perioperative monitoring has to be re-evaluated.

Anesthesia, General↗
PubMed2001

[Popliteal (Baker's) cyst in a patient with tubercular arthritis. Report of a case and review of the literature].

The Baker's cyst is a distension of the bursa subtendinea and is caused by noninfectious knee effusion secondary to arthrosis, meniscal tears, trauma, rheumatoid arthritis, gout, or any other form of sinovitis, like rheumatoid arthritis. An infected popliteal cyst is much less common; tuberculous arthritis is exceptional, in fact only four cases are described in literature. Herein we describe an additional tbc case of a 51 years old men, who has been initially treated with cytostatic and corticosteroid agents, for a suspected rheumatoid arthritis. The review of the literature suggests the importance of a correct approach to the diagnosis, based on the analysis and culture of the synovial fluid, because delays latency of effective antibiotic therapy can result in permanent joint damage that invalidate the patients.

Humans↗
PubMed2000

The genome sequence of the plant pathogen Xylella fastidiosa. The Xylella fastidiosa Consortium of the Organization for Nucleotide Sequencing and Analysis.

Xylella fastidiosa is a fastidious, xylem-limited bacterium that causes a range of economically important plant diseases. Here we report the complete genome sequence of X. fastidiosa clone 9a5c, which causes citrus variegated chlorosis--a serious disease of orange trees. The genome comprises a 52.7% GC-rich 2,679,305-base-pair (bp) circular chromosome and two plasmids of 51,158 bp and 1,285 bp. We can assign putative functions to 47% of the 2,904 predicted coding regions. Efficient metabolic functions are predicted, with sugars as the principal energy and carbon source, supporting existence in the nutrient-poor xylem sap. The mechanisms associated with pathogenicity and virulence involve toxins, antibiotics and ion sequestration systems, as well as bacterium-bacterium and bacterium-host interactions mediated by a range of proteins. Orthologues of some of these proteins have only been identified in animal and human pathogens; their presence in X. fastidiosa indicates that the molecular basis for bacterial pathogenicity is both conserved and independent of host. At least 83 genes are bacteriophage-derived and include virulence-associated genes from other bacteria, providing direct evidence of phage-mediated horizontal gene transfer.

Bacterial Adhesion↗
PubMed1999

[Interactions of intravenous anesthetics with cerebral alpha-2-adrenoceptors].

OBJECTIVE: Up to date the exact mechanisms of action of anaesthetics on structures of the central nervous system have not been elucidated. Agents acting on central alpha 2-adrenoceptors have been demonstrated to possess potent sedative properties. Beside the classical agonists, general anaesthetics that are currently in clinical use e.g. etomidate have also been shown to act on alpha 2-adrenoceptors. Thus, the aim of this study was to study the effect of the intravenous anaesthetic agents propofol and ketamine on the binding of the specific alpha 2-adrenoceptor agonist paraiodoclonidine at cerebral alpha 2 adrenoceptors. METHODS: After approval of the local animal care committee brain tissue of six Wistar rats was removed and frozen at -80 degrees C. The tissue was sectioned in 15-20 microns thick slices. After washing in TRIS-buffer (pH = 7.5) the slices were incubated with 2.5 nM 125I-paraiodoclonidine (PIC) for determination of specific binding. Unspecific binding was determined in presence of 200 microM unlabeled clonidine. Displacement experiments were performed in presence of propofol (11-530 microM) and ketamine (52-1100 microM) and evaluated autoradiographically. Average exposure time was three days. All films were then analysed by densitometry. Statistical significance calculated by Student's t-test was assumed at a level of p < 0.05. RESULTS: Only at the highest concentration of propofol and ketamine an effect on PIC binding was noticeable. Neither propofol nor ketamine was able to displace PIC completely from cerebral alpha 2-adrenoceptors. CONCLUSION: In contrast to other anaesthetics such as etomidate which was demonstrated to displace PIC completely from alpha 2-adrenoceptors, propofol and ketamine exerted only minor effects on the binding of PIC even at concentrations that exceeded clinical concentrations. These data suggest that an additional site of action of these anaesthetics at cerebral alpha 2-adrenoceptors beside the known actions on GABA receptors or NMDA receptors is unlikely.

Adrenergic alpha-Agonists↗
PubMed1999

Aromatase activity of human granulosa cells in vitro: effects of gonadotrophins and follicular fluid.

The aim of this study was to assess whether human dominant follicular fluid has the ability to modulate aromatase activity and/or granulosa cell proliferation. Dominant follicular fluid was obtained by laparoscopy before the luteinizing hormone surge in naturally cycling women while granulosa cells used in the tests were obtained from in-vitro fertilization patients. Aromatase was measured by the tritiated water release assay, following a 48 h incubation with follicular fluid and serum, and expressed for 5x10(4) granulosa cells. The effects of a range of follicular fluid or serum concentrations (2.5, 5, 10 and 20%) were compared. A decrease in aromatase activity was observed when high follicular fluid concentrations (20%) (P < 0.01) were added. Low concentrations (2.5%) of follicular fluid significantly increased cell proliferation (P < 0.01) as compared to basal values (0%). No further stimulation was however observed when concentrations increased up to 20%. Further characterization of these compounds is required to understand how they may modulate maturation of the dominant follicle.

Aromatase↗