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PubMed1995

Polarized light scattering: a biophysical method for studying bacterial cells.

We outline a method which uses differentially polarized light scattering to study the properties of bacterial cell suspensions, i.e., spores of Bacillus Subtilis. The identification of bacterial cells of different strains, with and without plasmid insertion, was performed by means of differential polarization light scattering (DPLS). The samples displayed distinct angular behaviors for the S14 and S34 normalized scattering parameters of the Mueller matrix depending on the strain and on a plasmid insertion in the chromosomal unit. These experiments, performed blindly, point out the possibility of achieving real time identification of micro-organisms by DPLS spectrometry.

Bacillus subtilis↗
PubMed1997

[Transcutaneous or transconjunctival peribulbar anesthesia?].

BACKGROUND: Transconjunctival peribulbar anesthesia is reported to permit better identification of the bulbar limits because of a better view into the fornix; it is also said to be less painful compared to transcutaneous peribulbar anesthesia. The aim of our study was to compare the two injection techniques. PATIENTS AND METHODS: This study comprised 46 patients undergoing eye operations under local anesthesia. They were allocated randomly in a prospective and simple masked study. Twenty-three patients received transconjunctival injections and 23 patients transcutaneous peribulbar injections. Before injection, all patients received Oxybuprocain eyedrops for anesthesia of the conjunctiva. In all cases no separate injections for lid akinesia were performed. Before and 20 min after the injection, the following parameters were assessed: pain score (visual analog scale), frequency of conjunctival chemosis and the necessity for supplemental anesthesia. For identification of the bulbar limits we checked if it was possible to see the caudal and the cranial fornix. RESULTS: The transconjunctival injection was significantly (P = 0.05) more painful (5.6 +/- 2.4) than the transcutaneous injection (4.2 +/- 2.4). Among the patients with transconjunctival injection, in 66.6% the cranial fornix could not or was only poorly seen. CONCLUSIONS: Transconjunctival peribulbar anesthesia appears not to be more advantageous than transcutaneous peribulbar anesthesia.

Anesthesia, Local↗
PubMed1998

Investigation of spectral reproducibility in direct analysis of bacteria proteins by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.

Matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry (TOFMS) can be used for rapid detection of bacteria proteins in a crude mixture. It can potentially be used as a tool for bacterial identification based on the mass spectral patterns or the appearance of some characteristic mass peaks. However, there are many experimental parameters that can potentially have a strong effect on the observed mass spectra. The objective of this work is to address the mass spectral reproducibility issue. Several experimental parameters that may affect the MALDI spectra are systematically investigated. Results of spectral comparison from two laboratories with different operators and instrumentation are presented. It is demonstrated that minor variations in the sample/matrix preparation procedures for MALDI and in the experimental conditions used for bacterial protein extraction can result in a significant change in the observed spectra, though a number of peaks are conserved in the spectra obtained under different experimental conditions from the same bacterial sample. These conserved peaks may potentially be used as the biomarkers for bacterial identification. It is stressed that this type of investigation on spectral reproducibility should be carried out for different bacterial species in order to identify the mass spectral peaks that are consistently detected regardless of operator and nominal variations in sample preparation approach.

Bacillus thuringiensis↗
PubMed1983

Visual discrimination, categorical identification, and categorical rating in brief displays of curved lines: implications for discrete encoding processes.

Visual discrimination, categorical identification, and categorical rating measurements were made on sets of curved-line stimuli drawn from a theoretically uniform continuum with curvature parameter s. In Experiment 1, discriminability of pairs of curved lines separated by a constant distance on the s scale was measured at successive points along the scale. Curved lines were presented four at a time in a 100-msec display, which was followed by a random-dot mask. Discrimination performance was found to vary nonsmoothly with s. In Experiment 2, a categorical identification task was performed in which subjects labeled the curved-line stimuli of Experiment 1 straight, just curved, and more than just curved. From these data, a theoretical discrimination performance was computed that was closely congruent to the discrimination performance of Experiment 1. In Experiment 3, three different categorical rating scales with two, three, and four intervals were tested and each was shown to be less effective than the categorical identification scale for predicting discrimination performance. Mean ratings were, however, highly linear with s, suggesting that the curved-line continuum was psychometrically uniform. Experiment 4 provided further evidence for the uniformity of the curved-line continuum by measuring conventional acuity for curvature. Two rather than four curved lines were presented in each display; duration was increased to 2 sec; and the poststimulus mask was omitted. Acuity was found to vary linearly with s. It was concluded that under conditions in which attention is distributed over a number of elements in the field and in which viewing and effective visual processing time are restricted, performance in discriminating curved-line stimuli may be determined by relatively coarse, discrete visual processes.

Adult↗
PubMed1997

Activity profiles of carcinogenicity data: application in hazard identification and risk assessment.

Animal cancer data play a primary role in human risk assessment due to the limited epidemiological data. The current database of test results from the NCI/NTP rodent bioassays provide valuable information concerning the carcinogenic potential of hundreds of environmental agents. An approach is presented to reduce and graphically display these data as activity profiles to allow visualization and assessment of tumor response trends across multiple parameters, e.g. species, sex, target site, and route of exposure. Spreadsheet graphics are used to construct the profiles organized on the multiple parameters of carcinogenicity in a format that enables comparative analysis among chemicals. Several example applications are described to illustrate the value of activity profiles in hazard identification and risk assessment. The NCI/NTP data used in developing this concept are from the Carcinogen Potency Database (CPDB) complied by Gold et al. (Environ. Health Perspect. 103 (Suppl. 8) (1995) 3-122). Computer links to the underlying details in the CPDB are maintained such that specific histopathologies at individual tumor sites, duration of the study, dose-response data, and notes related to diet, survival, treatments, and the authors evaluation are available to aid in the assessment process. The profiles display carcinogen potency based on the tumorigenic dose rate 50 (TD50), i.e. the chronic dose rate that would induce tumors in half of the test animals at the end of their standard lifespan adjusting for spontaneous tumors. The TD50 values provide an index for establishing a relative potency ranking of the chemicals for any specific parameter, such as species or target site. An example ranking of hepatocarcinogens is presented to illustrate relative potencies for chemical analogs. The rank order indicates that the degree and type of halogenation of alkanes has a direct bearing on the carcinogenic potency of these compounds.

Administration, Oral↗
PubMed1996

N-nitroso compounds in the gastric juice of normal controls, patients with partial gastrectomies, and gastric cancer patients.

BACKGROUND: It has been suggested that the variation of biochemical and microbiological parameters in the gastric juice may play a role in the development of gastric cancer. In the present study we concurrently assessed the presence of N-Nitroso compounds (NOC) and their precursors, bacteria and carcinoembryonic antigen (CEA) in the gastric juice of normal controls, patients with gastric resection, and advanced gastric cancer. METHODS: Detailed analyses of biochemical and microbiological parameters such as pH, nitrite (NO2) concentration, N-nitroso compounds (NOC) concentration, carcino-embryonic antigen (CEA) level, total viable counts (TVC), nitrate-reductase positive bacterial counts (NRPBC), and identification of micro-organisms were carried out. RESULTS: Significantly higher mean pH values, NO2, NOC and CEA concentrations, TVC, and NRPBC were found in partial gastrectomies compared with normal controls, and all these intragastric parameters were significantly higher in patients with gastric cancer than in those with partial gastrectomies. As far as surgical methods are concerned, higher mean pH values, NO2 and NOC concentrations, TVC, NRPBC, and anaerobic bacterial counts were observed in the juice of patients with Billroth II compared with Billroth I gastrectomies. Apart from the type of surgical reconstruction, higher mean NOC levels were recorded in patients with more severe histological changes and H. pylori infection. CONCLUSIONS: All these data suggest that the presence of high levels of NOC in the gastric juice of gastroresected patients can be considered a risk factor of gastric stump cancer.

Adult↗
PubMed2004

Kinetics of intraoperative fluorescence diagnosis of parathyroid glands.

OBJECTIVE: Identification of parathyroid glands is often a challenge even for experienced surgeons. The feasibility and efficacy of fluorescence diagnosis for localization of parathyroids has already been proven in an experimental setting. In preparation for a clinical application of this technique in patients undergoing surgery for hyperparathyroidism, we evaluated the kinetics of fluorescence diagnosis. DESIGN AND METHODS: Fifty rats were randomized into eight groups with different photosensitization parameters using the photosensitizer aminolevulinic acid (ALA): a peritoneal lavage was performed with either 1.5 or 3.0% ALA solution and the induced photosensitization times varied from 0.5, 1 and 2 to 4 h. Under special fluorescence illumination, D-light, the exposed operative site with thyroid, parathyroid glands and neck muscles was examined. The identified parathyroid glands were studied according to fluorescence intensity by spectrometric measurement and compared with surrounding tissue. RESULTS: Photosensitizer accumulation in parathyroid glands, indirectly measured by spectrometry, was up to 3.2 times higher than in thyroid and 2.6 times higher than in muscle tissue (2 h photosensitization with 3.0% ALA). Using 1.5% ALA, the optimum fluorescence intensity and ratio/contrast was slightly lower (parathyroid-to-thyroid ratio x 3.0, parathyroid-to-muscle ratio x 1.9) but was reached earlier (1 h) and hence considered as the parameter of choice for a clinical application. CONCLUSIONS: In future clinical application, intraoperative fluorescence diagnosis is expected to increase the ease of identification of atypically located or supernumeric glands. In combination with preoperative diagnostics, this may result in reduced operation time and avoidance of persistent hypercalcaemia.

Aminolevulinic Acid↗
PubMedDate not supplied

Endocardial border identification in two-dimensional echocardiographic images: review of methods.

A basic goal in the analysis of echocardiographic images is to identify the locations of the endocardial borders. This is necessary in order to create three-dimensional reconstructions, and to derive precise quantitative parameters from the images. Endocardial borders can be identified manually; however, this is time-consuming, inconvenient, and liable to human subjectivity. For this reason there has been a great deal of interest in automatic border identification methods. In recent years numerous studies have been published, describing a wide variety of proposed border identification algorithms. In spite of the large number of published studies, however, the relative merits of the various methods remain unclear. In this paper the various analysis techniques are reviewed and discussed. The reasons for the lack of definitive conclusions regarding the utility of these methods are described. Finally, the basic methodological requirements necessary for empirical evaluation of border identification techniques are described.

Algorithms↗
PubMed2006

Stability of atenolol, acebutolol and propranolol in acidic environment depending on its diversified polarity.

The main objective of this research was to investigate the relationship between the polarity of atenolol, acebutolol, and propranolol described by logP and kinetic and thermodynamic parameters characterizing their degradation process in acidic solution. Hydrolysis was carried out in hydrochloric acid at molal concentrations of 0.1 mol/L, 0.5 mol/L, and 1 mol/L for 2 hr at 40 degrees C, 60 degrees C, and 90 degrees C. Chromatographic-densitometric method was used for the determination of drugs under investigation. The identification of degradation products was carried out by using 1H NMR. The degradation processes that occurred in drugs under investigation are described with kinetic parameters (k, t0.1, and t0.5) and energy of activation (Ea). It has been found that the stability of drugs increases toward lipophilic propranolol in the assumed experimental model. The rate constants k decrease, contrary to t0.1, t0.5, and Ea, which vary comparably to logP, thus increasing from the most hydrophilic atenolol, through acebutolol, of lower polarity, to the most lipophilic propranolol. This study demonstrated that the stability of chosen beta-adrenergic blocking agents increases with their lipophilicity.

Acebutolol↗
PubMed2003

Niche-specific association of Aeromonas Ribotypes from human and environmental origin.

A total of 88 Aeromonas isolates from distinct locations and sources (39 from extraintestinal infections, 31 from diarrhoeic, ten from non-diarrhoeic faeces, all human, and eight from fresh water) were subjected to phenospecies identification, serotyping, ribotyping and detection of some virulence markers. The strains belonged to four different phenospecies marked by 19 O serogroups and 38 ribotypes. No strong correlation between these parameters was found, and no group, as defined by the typing methods, could be characterized with a particular set of virulence markers. There was a clear association of ribotypes with the source of the strains. Cluster analysis allowed the identification of a complex of ribotypes belonging to distinct but related sources, including clinical and environmental isolates. These results suggest that ribotyping may be an epidemiological tool suitable for the study of Aeromonas infections.

Aeromonas↗
PubMed2005

[Classification of terpenes and terpene oxides in volatile oil of Fruit of Acanthopanax senticosus (Rupr. Et Maxim) Harms with gas chromatographic retention parameters].

Gas chromatographic (GC) retention parameters (A and B values) for 24 volatile compounds in volatile oil of Acanthopanax senticosus (Rupr. Et Maxim) Harms were obtained from the retention times under five temperature-programming conditions with self-developed GC_AB software based on Levenberg-Marquardt method. The correlation analysis between A and B parameters of terpene and its oxides was carried out. Good linear relationships between A and B parameters were built for seven monoterpenes (C10H16) , nine sesquiterpenes (C15H24), three monoterpene oxides (C10HnO) and three sesquiterpene oxides (C15HnOx) at the same carbon number, respectively. But poor A-B linearity was built for the group formed from monoterpenes and monoterpene oxides or that formed from sesquiterpenes and sesquiterpene oxides at the same carbon number. At the same time the A-B relationships for monoterpenes, sesquiterpenes and their oxides are not collinear. Therefore, this discipline is applied in the assistant identification for terpenes with different carbon numbers and in the classification between terpenes and their oxides. It shows that GC retention parameters calculated from retention times under several temperature-programming conditions are useful for the classification of monoterpenes, sesquiterpenes and their oxides in the analysis of volatile oils from traditional Chinese herbs.

Chromatography, Gas↗
PubMed1993

Measurement of beta-thromboglobulin and platelet factor 4 to follow up patients with artificial heart valves.

Efficient antithrombotic therapies are necessary for the prevention of thrombotic complications in patients with artificial heart valves. Antiplatelet drugs are commonly used since platelet activation is a feature frequently found in these pathologic conditions. The measurement of beta TG and PF4 is useful for the diagnosis of platelet activation, which may increase the thrombotic risk. Two commercially available ELISA kits for beta TG and PF4 were tested and compared with the corresponding RIA methods used previously. Coefficients of correlation were 0.976 for beta TG and 0.985 for PF4. Both methods gave identical results, although RIA was expressed in nanograms per milliliter, whereas ELISA results were in international units per milliliter by comparison with International Standards. For both parameters 1 IU/ml was found to be almost equal to 1 ng/ml. beta TG was elevated in the group of patients with heart valves (57.28 IU/ml); so was PF4 but to a lesser extent (11.28 IU/ml). The mean concentrations on a normal population were, respectively, 22.40 (+/- 5.15) IU/ml and 4.10 (+/- 2.02) IU/ml. The monitoring of patients with heart valves allowed the identification of two distinct groups: those who had persistent elevated levels of beta TG and PF4, and those whose levels of the same parameters were in the subnormal ranges. All the thrombotic complications were observed in the first group and were preceded by an elevation of platelet markers. beta TG was the most predictive and correlated closely with the evolution of the clinical state. Cerebrovascular accidents were the commonly observed complications. These patients were treated by hypocoagulant therapy and with antiplatelet drugs.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed2001

A forward model-based validation of cardiovascular system identification.

We present a theoretical evaluation of a cardiovascular system identification method that we previously developed for the analysis of beat-to-beat fluctuations in noninvasively measured heart rate, arterial blood pressure, and instantaneous lung volume. The method provides a dynamical characterization of the important autonomic and mechanical mechanisms responsible for coupling the fluctuations (inverse modeling). To carry out the evaluation, we developed a computational model of the cardiovascular system capable of generating realistic beat-to-beat variability (forward modeling). We applied the method to data generated from the forward model and compared the resulting estimated dynamics with the actual dynamics of the forward model, which were either precisely known or easily determined. We found that the estimated dynamics corresponded to the actual dynamics and that this correspondence was robust to forward model uncertainty. We also demonstrated the sensitivity of the method in detecting small changes in parameters characterizing autonomic function in the forward model. These results provide confidence in the performance of the cardiovascular system identification method when applied to experimental data.

Autonomic Nervous System↗
PubMed2000

Milk identification of different species: 13C-NMR spectroscopy of triacylglycerols from cows and buffaloes' milks.

Triacylglycerols from cows and buffaloes' milk fat were investigated by 13C nuclear magnetic resonance (NMR) spectroscopy. By the addition of pure triacylglycerols standards, we identified the resonances of both milk fats, and the peaks were used for qualitative and quantitative analysis of acyl groups. Multivariate analysis treatment of triacylglycerols distribution and composition parameters enabled us to identify milk. This study shows that NMR can safely be used to quantitate milk fatty acid content, providing unique information for milk identification of different animal species.

Animals↗
PubMed2006

[Estimation of smell sense rehabilitation in patients after total laryngectomy].

The loss of sense of smell significantly decreases a quality of life after total laryngectomy. That is why this problem should be considered within a complex rehabilitation of laryngectomized patients. The smell exercises ought to start parallely to the speech rehabilitation. The aim of our study was to estimate the efficacy of smell rehabilitation after total laryngectomy. 59 persons after total laryngectomy attending the fourteen days long rehabilitation camp were examined. All the patients had the examination of three smells identification (lemon, mint and anise) made before the beginning of exercises. All the persons had also the efficacy of air aspiration through the nose measured. The control examination of those parameters was conducted after fourteen days of exercises of making the negative pressure in the throat and nasopharynx directing the air flow into the olfactory area of the nose. We confirmed a statistically significant differences between the smell identification and the force of aspiration before and after rehabilitation. We confirmed that patient's age and the time from laryngectomy have the influence into the efficacy of smell rehabilitation.

Adult↗
PubMed1990

Identification and characterization of a high-affinity glutamate-controlled TCP binding site in rat brain postsynaptic densities.

The kinetic and equilibrium binding parameters of the phencyclidine receptor ligand [3H]N-[1-(2-thienyl)cyclohexyl]piperidine (TCP) to a postsynaptic density (PSD) subcellular fraction from rat brain were investigated. A single site was found, which was identified as the high-affinity TCP binding site by competition with dibenzocycloalkenimine (MK-801). In contrast, [3H]TCP binds to two sites on the plasma membrane fraction used as a precursor for PSD; on both fractions, [3H]TCP binding responds to glutamate by an increase of the association rate, the dissociation constant and the number of sites being unchanged. In the PSD fraction [3H]3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid (CPP), an antagonist specific for the N-methyl-D-aspartate (NMDA) site, bound to high- and low-affinity sites. These results ascertain the presence and identity of synaptic NMDA-gated ion channels, which are assumed in the current hypothesis about excitotoxicity, long-term potentiation and learning.

Animals↗
PubMed1978

Identification of the transferrin receptor of the rabbit reticulocyte.

Reticulocytes were separated on the basis of density by isopycnic centrifugation in dextran gradients. This parameter was shown to correlate with the degree of maturity of the cells. Lactoperoxidase iodination of cells of different densities followed by sodium dodecyl sulfate (NaDodSO4) electrophoresis revealed a 190 000 molecular weight protein which was well labeled in early reticulocyte membranes. Efficiency of labeling decreased as the cells increased in density, and high specific activity iodination of mature erythrocytes did not result in the labeling of any species near this molecular weight. Inclusion of rabbit transferrin prior to the iodination procedure resulted in a specific loss of labeling of this 190 000 molecular weight species. When steps were taken to clear endogenous transferrin from the membranes, the labeling of this species was enhanced. These observations are consistent with the concept that transferrin can block the lactoperoxidase catalyzed iodination of this membrane protein by specifically associating with it. Coomassie blue and periodic acid-Schiff staining of NaDodSO4 gels of these membranes revealed that a glycoprotein present at this molecular weight is lost during the course of reticulocyte maturation. It is concluded from these studies that a glycoprotein of molecular weight 190 000 constitutes the transferrin receptor in the reticulocyte membrane.

Animals↗
PubMed2001

Identification of factors predictive of lower extremity vein graft thrombosis.

OBJECTIVE: The objective of this study was to assess the prognostic value of hemodynamic parameters measured with duplex ultrasound scan, together with other important graft and patient characteristics, in predicting lower extremity vein graft thrombosis. METHODS: A total of 165 lower extremity vein grafts were entered prospectively into a postoperative duplex ultrasound scan surveillance program with examinations performed at 1, 2, 3, 4, 6, 9, 12, 18, and 24 months, and annually thereafter. Duplex scan-derived blood flow velocity measurements were recorded at 1562 patient visits over 7 years. Graft patency was determined after each visit, and an analysis of factors predictive of vein graft thrombosis was performed with Poisson regression. RESULTS: Thirty-two episodes of first-time graft thrombosis occurred, 23 of which were permanent. One-, 3-, and 5-year secondary graft patency rates were 90%, 86%, and 79%, respectively. In multivariate analyses, duplex scan velocity measurements predictive of lower extremity graft thrombosis included the maximum velocity ratio (Vr) in association with a graft stenosis and the mean graft peak systolic velocity (MGV) within nonstenotic portions of the body of the graft. The incidence of graft thrombosis among grafts without inflow/outflow stenoses, with Vr less than 3.5, and with MGV 50 cm/s or more, was 2.9% per year. Incidence rates were considerably higher among grafts with a of Vr of 3.5 or more (incidence rate ratio = 7.0; 95% CI, 3.4-14.6) or an MGV less than 50 cm/s (incidence rate ratio = 6.5; 95% CI, 3.3-13.1). In grafts without identifiable inflow, outflow, or graft stenoses, there was no association between MGV and the risk of graft thrombosis. CONCLUSION: Duplex scan velocity measurements are valid predictors of impending graft thrombosis. A Vr of 3.5 or more and an MGV less than 50 cm/s are the best predictive measures. Repair of correctable graft lesions with a Vr of 3.5 or more, or inflow, outflow, or graft lesions associated with an MGV less than 50 cm/s are recommended. Grafts without detectable inflow, outflow, or graft stenoses, regardless of MGV, may be safely followed.

Adolescent↗