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Biomedical subjects

F Paul

Publications and source records attributed to F Paul.

At least 19 recordsLinked to original sources
PubMed2006

[Relapsing reversible posterior leukoencephalopathy after chemotherapy with cisplatin and 5-fluorouracil].

We report a 37-year-old patient with gastric cancer who suffered two distinct episodes of generalized tonic-clonic seizures during ongoing chemotherapy with cisplatin and 5-fluorouracil. Cranial MRI revealed reversible posterior leukoencephalopathy (RPL) that remitted completely without any specific therapy after discontinuation of the chemotherapeutic drugs. Interestingly, RPL occurred repeatedly in our patient following the single chemotherapy cycles, which has not been described so far. This syndrome is clinically relevant for differential diagnosis of bilateral ischemia of the posterior cerebral arteries. An overview of the literature and necessary diagnostic procedures is given.

Adult↗
PubMed2005

Prebiotic effects of oligosaccharides on selected vaginal lactobacilli and pathogenic microorganisms.

The purpose of this study was to select endogenous human vaginal lactobacilli strains on the basis of the main probiotic properties observed in the vaginal environment in order to use them for the evaluation of the potential prebiotic properties of oligosaccharides. From vaginal samples of 50 women with a normal flora, 17 lactobacilli strains were first isolated because of their high level of hydrogen peroxide production. Then six strains were selected mainly for their ability (i) to adhere to vaginal cells, (ii) to produce compounds in sufficient amount, such as lactic acid, having an inhibitory action on pathogens, and less importantly, (iii) to demonstrate arginine deiminase activity. These six strains were found to belong to three distinct species: Lactobacillus crispatus, L. jensenii and L. vaginalis. One strain of each species was chosen as a potential vaginal probiotic strain with regard to our criteria. These three strains were then used to evaluate the prebiotic properties of different oligosaccharide series: two fructooligosaccharide series (FOS Actilight and FOS Raftilose) and two glucooligosaccharide series varying by their osidic linkages (alpha-1,6/alpha-1,4 GOS and alpha-1,2/alpha-1,6/alpha-1,4 GOS). The test was based on the ability of the oligosaccharides to promote the growth of the three beneficial strains selected but not of pathogenic microorganisms often encountered in urogenital infections such as Candida albicans, Escherichia coli and Gardnerella vaginalis. Oligosaccharide hydrolysis was followed by HPLC analysis. This revealed that two oligosaccharide series (FOS Actilight DP3 and all alpha-1,6/alpha-1,4 GOS DP > or = 4) were used only by the lactobacilli strains, the pathogenic microorganisms being unable to metabolise them. The selected lactobacilli and oligosaccharides are good candidates for incorporation in a formula to prevent vaginal infections.

Journal Article↗
PubMed2002

Real-time monitoring of stain formation and removal on calcium hydroxyapatite surfaces using quartz crystal sensor technology.

Stain formation, stain inhibition and stain removal may be monitored in real-time using a novel method employing a quartz crystal resonance sensor (QCR), based upon quartz crystal microbalance (QCM) technologies. Crystalline hydroxyapatite (HA) surfaces were prepared on phosphate-terminated, polymer-modified gold surfaces of quartz crystal transducers. The resulting sensors were placed in a specially constructed flow cell, and the interaction of adsorbates from the tea stain solution monitored as a function of time. The ability of sodium tripolyphosphate (STP) to remove extrinsic stain and also to inhibit its formation was examined. The adsorption of material from the staining solution passed over the sensor was clearly observable, and once bound, the crystal based real-time data suggest that tea adsorbates were not removed in the absence of an active under conditions of continuous flow. STP was shown to rapidly remove existing stain, and exhibited a clear inhibitory action on stain formation irrespective of whether the HA had been previously exposed to tea chromogens. The continuous data generated by the QCR technique were in good agreement with the results obtained using a discontinuous spectrophotometric method. The presently described quartz crystal model for extrinsic dental stain should provide a valuable tool to aid understanding of the interactions of staining agents with a crystalline HA surface as a model tooth surface, and to evaluate the efficacy and mode of action of STP and putative stain removal agents.

Coloring Agents↗
PubMed2001

A quartz crystal resonant sensor (QCRS) study of HSA--drug interactions.

Human serum albumin (HSA) was immobilised on the gold surface of a quartz crystal resonance sensor (QCRS) and exposed to warfarin and diazepam. Distinct decreases in frequency of differing magnitudes were observed upon exposure of the protein to each of the compounds suggesting strongly that a ligand interaction was occurring. Moreover, as sequential exposure in any order was observed to yield distinct repeatable frequency decreases for the ligands indicated, screening for site specific binding may be possible. Identically immobilised bovine serum albumin (BSA) gave no response to either compound.

Animals↗
PubMed2001

A rapid, non-destructive method for the determination of Staphylococcus epidermidis adhesion to surfaces using quartz crystal resonant sensor technology.

AIMS: To investigate the use of quartz crystal resonant sensor (QCRS) technology to determine the adhesion of Staphylococcus epidermidis to fibronectin-coated surfaces. METHODS AND RESULTS: QCRS sensors (14 MHz) with 4 mm gold electrodes were coated with fibronectin and exposed for 15 min to suspensions of Staph. epidermidis ranging in concentration from 1 x 10(2) to 1 x 10(6) cfu ml(-1). Changes in resonant frequency were recorded and showed a linear relationship with the logarithm of cell concentration over the range tested. CONCLUSIONS: QCRS technology was shown to be a rapid, sensitive and non-destructive method for measuring the adhesion of bacteria to surfaces. SIGNIFICANCE AND IMPACT OF THE STUDY: This report demonstrates that QCRS technology has the potential to be used for a range of applications requiring measurement of bacteria on surfaces. In particular, it may be used for the real-time monitoring of bacterial biofilm formation.

Bacterial Adhesion↗
PubMed2001

Patient information: involving the user group.

A review within an acute hospital trust identified problems with in-house information, including a lack of patient involvement, poor quality print and over-use of technical language. A project was set up to improve the quality of the trust's information leaflets.

Educational Status↗
PubMed1999

Application of the quartz crystal microbalance to the monitoring of Staphylococcus epidermidis antigen-antibody agglutination.

The change in solution properties due to the agglutination of an antigen with its specific antibody has previously been used as a marker of infection. This method has been modified to allow the binding activity between species to be followed using the frequency response of a quartz crystal microbalance (QCM). The Bayston agglutination plate assay for Staphylococcus epidermidis has been modified to allow the electrode of a QCM to act as a direct sensor for the change in solution properties as agglutination occurs. Antibody and antigen were introduced to the crystal surface and the agglutination process was followed as a change in crystal resonant frequency. Serum, known to be infected with the organism, gave a titre of 3.9x10(-2)% v/v (-118 Hz, +/-12 SD, N = 9) matching that given by triplicate plate assay. Uninfected serum gave no frequency changes at this concentration, yielding a titre of 2.5x10(-2)% v/v again matching the plate titre (N = 3). Infected serum gave responses 40 times faster then those of the uninfected serum. The piezoelectric quartz crystal method gave a positive or negative diagnosis in <15 min compared with the 24 h required for the plate assay.

Agglutination Tests↗
PubMed1999

The tissue distribution of the human beta3-adrenoceptor studied using a monoclonal antibody: direct evidence of the beta3-adrenoceptor in human adipose tissue, atrium and skeletal muscle.

OBJECTIVE: To develop a monoclonal antibody that recognises an epitope of the native beta3-adrenoceptor expressed on the extracellular surface of human cells and tissues. DESIGN: A high affinity monoclonal antibody, Mab72c, was raised against the human beta3-adrenoceptor expressed on a transfected mammalian cell line. RESULTS: In CHO (Chinese hamster ovary) cells transfected with beta3-adrenoceptor cDNA, antibody labelling was found to be proportional to receptor density measured by the binding of the radiolabelled beta-adrenoceptor antagonist, [125I]-iodocyanopindolol. The use of Mab 72c has demonstrated the expression of the beta3-adrenoceptor in a variety of human tissues, including gall bladder, prostate and colon, where a mRNA signal had been detected previously. This study also provides the first direct demonstration of the expression of beta3-adrenoceptors in human skeletal muscle, atrium and adipose tissue. CONCLUSION: The development of this antibody represents an important addition to the armentarium of reagents that are available to study the localisation of beta3-adrenoceptors in human tissues.

Adipose Tissue↗
PubMed1998

Dissolution of gallbladder stones with methyl tert-butyl ether and stone recurrence: a European survey.

Since there are now several ways to treat symptomatic gallstone disease, one is able to select treatment on the basis of the patient's comfort, the practicability, effectiveness, and side effects of the technique, and the relative costs. In order to assess the present status of contact dissolution with methyl tert-butyl ether with regard to these aspects, the present enquiry reports the data of 21 European hospitals. Eight hundred three patients were selected for contact litholysis of cholesterol gallbladder stones using methyl tert-butyl ether. Percutaneous transhepatic puncture of the gallbladder was performed under x-ray or ultrasound guidance. Dissolution rate, side effects, and treatment times of 268 patients from one single center were compared to those of 535 patients from the other 20 centers. Two hundred sixty-four patients were followed for five years to assess stone recurrence. Physicians were asked how they assessed the expenditure of the method, the discomfort to the patients, and the staffing situation. Patients were asked to indicate their acceptance on an analog scale. Puncture was successful in 761 (94.8%) patients. Prophylactic administration of antibiotics was not necessary. Stones were dissolved in 724 (95.1%) patients. In 315 (43.5%) sludge remained in the gallbladder. The most severe complication was bile leakage, which led 12 (1.6%) patients to have elective cholecystectomy. Toxic injuries due to the ether were not reported. Method-related lethality amounted to 0%, 30-day-lethality to 0.4%. Stone recurrence rate was about 40% in solitary stones and about 70% in multiple stones over five years. Patients with multiple stones developed recurrent stones almost twice as often as those with solitary stones. The probability of stone recurrence in patients with sludge in the gallbladder after catheter removal was not statistically significantly different from those without sludge. Seventy to 90% of the centers found the puncture to be simple and not distressing for patients and the relation between expenditure and therapeutic success to be acceptable. The acceptance of contact litholysis by the patients was excellent. Contact litholysis when applied by an experienced team provides real advantages in the treatment of gallstone disease. The method is technically simple, well accepted by the patients, and can be easily applied in community hospitals. Contact litholysis may be of particular value in patients who are not suitable for anesthesia or surgery.

Adolescent↗
PubMed1997

A clinical, epidemiological and laboratory study on avoiding the risk of transmitting viral hepatitis during vaccinations with the Dermojet protected by an anticontaminant disposable device.

Jet injectors may transmit blood-borne infections, such as hepatitis B virus (HBV) and human immunodeficiency virus (HIV). To evaluate the safety of an anticontaminant disposable device which protects the jet injector apparatus, 22,714 healthy subjects were intradermally inoculated (38,162 inoculations) with a variety of vaccines. All the subjects were systematically followed-up clinically and epidemiologically for 6-18 months after inoculation; blood samples from 1619 subjects, before and 60-75 days after inoculation, were examined by enzyme-linked immunosorbent assay (ELISA) for HBV, hepatitis C virus (HCV) and HIV. Before vaccination 212 (13.09%) subjects were positive: 204 positive for HBV markers and eight for the HCV marker. None of the subjects were positive for the anti-HIV marker. During the clinico-epidemiological surveillance and the laboratory investigations mentioned above no clinical viral hepatitis B or C case and no seroconversion to positivity for HBV or HCV markers among the susceptible persons in the group were reported. Considering that in similar situations there is a theoretical risk of transmission as high as 1 per 388 to 1 per 3367 injections and that in our case 38,162 inoculations were performed in 22,714 subjects with the same Dermojet protected by the same type of anticontaminant disposable device, no contamination risk being reported, the conclusion can be reached that jet injectors can be safely used in the medical practice if they are protected by the sterile anticontaminant disposable device.

Adolescent↗
PubMed1995

Discrimination of apoptotic thymocytes by forward light scatter.

The discrimination of apoptotic and normal rat thymocytes by forward-angle light scatter in the UV depended on the angle over which the scattered light was collected. To achieve good separation, the light needed to be collected over a narrow angle. It was also observed that apoptotic thymocytes gave less forward light scatter than normal cells, whereas, under identical conditions, apoptotic cells from a murine cell line gave more light scatter than their normal counterparts. We suggest that the forward light scatter of apoptotic cells is affected by several factors, including changes in cell size and in the internal structure of the cell.

Animals↗
PubMed1995

A nondegradative route for the removal of endotoxin from exopolysaccharides.

The potentiality of the Triton X-114 phase separation technique for the removal of lipopolysaccharide (LPS, endotoxin) from Klebsiella sp. I-714 exopolysaccharide (EPS) has been investigated. Classical purification and chemical detoxification methods were evaluated for their effectiveness in removing residual LPS, while preserving structural and functional integrity of EPS. Ultracentrifugation, Detoxi-Gel, and ion-exchange chromatography did not remove endotoxin, except gel filtration chromatography performed at 60 degrees C in sodium deoxycholate buffer. In this case, the bioactivity of the purified EPS fraction was significantly lowered, as was seen after alkaline hydrolysis treatment. Moreover, the acetic acid detoxification procedure hydrolyzed EPS. As an alternative, phase partitioning of EPS in Triton X-114 at low temperature provided a fast, mild, and efficient method for the removal of LPS as shown by a 100-fold reduction in Limulus amebocyte lysate (LAL) activity and only a 2-fold reduction in bioactivity. Gel filtration chromatography performed at 4 degrees C with Triton X-114 buffer and phase partitioning with the more hydrophilic Triton X-100 nonionic detergent at 75 degrees C led to a similar decrease in LAL activity. This novel application of Triton X-114 partitioning is a nondegradative alternative to the chemical detoxification of gram-negative bacterial EPS for vaccine production. Purification of endotoxin-contaminated polysaccharides prior to screening for biological activity should also benefit from this technique. The extraction scheme using Triton X-114 can be easily used in large-scale purification processes.

Cell Extracts↗
PubMed1995

Determination of the surface tension of block copolymer micelles by phagocytosis.

PURPOSE: This work was carried out to determine the surface tension of block copolymer micelles of 14C labelled ABA poly (oxyethylene-bi-isoprene-b-oxyethylene) which have a long circulating half life in animals. METHODS: The method used was that of phagocytosis. The percentage of micelles phagocytosed by human mononuclear cells was determined in solutions of different surface tension. RESULTS: The values obtained were 72 mN/m which may be predicted for a particle with a long circulating half life in animals. The method also gave an estimate of the surface tension for the mononuclear cells. CONCLUSIONS: This technique has the advantage of determining the surface tension of highly hydrated small particles including stable micelles in an environment similar to that in which they normally exist.

Humans↗