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PubMed2006

Analysis of lecithin-cholesterol mixtures using Raman spectroscopy.

FT-Raman spectroscopy has been used to investigate interactions between lecithin and cholesterol. Raman spectra of lecithin show multiple peaks which can be classified into three regions: hydrophobic chain, interfacial, and headgroup regions. Binary lipid mixtures (1:1, w/w, lecithin:cholesterol) were prepared by physical mixing, granulation, coprecipitation, hydration and heating (65 degrees C), and heating (120 degrees C). Regardless of the preparation method, no changes in the spectra were observed in the hydrophobic region. A shift in the wavenumber of the choline methyl asymmetric stretching mode was observed when the samples were prepared by coprecipitation, hydration and heating (65 degrees C), and heating (120 degrees C). This may indicate a modification of phospholipids in the headgroup region in these samples. The difference in degrees of frequency shift (physical mixing approximately granulation<coprecipitation approximately hydration and heating (65 degrees C)<heating (120 degrees C)) suggests that different levels of hydrogen bonding may have occurred in mixtures prepared with these methods. Multivariate analysis utilizing partial least squares regression based on selected wavenumber ranges was applied for the quantitative analysis of the amount of lecithin in lipid mixtures. Calibration models from physical mixing and heating (120 degrees C) exhibited lower R2 and root mean square error of cross validation (RMSECV) values compared to the other models suggesting lower sample homogeneity for these preparation methods. Low values of the mean absolute residues and mean Mahalanobis distances imply that the calibration model generated from physical mixing samples may be appropriate for quantitative analysis of lecithin in lipid mixtures prepared by any of the other techniques.

Chemistry, Pharmaceutical↗

PubMed1988

Prior antimicrobial therapy and resistance of Enterobacter Citrobacter and Serratia to third generation cephalosporins.

During a 6-month period all inpatients from whom Enterobacter, Citrobacter or Serratia. had been isolated were reviewed and information on selected variables recorded. Two groups, one including 19 patients with organisms resistant to third generation cephalosporins and the other 111 patients with susceptible organisms were compared. In the initial analysis, the mean number of antimicrobials received in the prior 2 months was the variable most strongly associated with isolation of resistant organisms (2.6 +/- 1.5 vs 1.5 +/- 1.6; P = 0.002). When patients who had received no antimicrobials were omitted from the analysis, the mean number of antimicrobials was similar (2.6 +/- 1.5 vs 2.3 +/- 1.5; P = 0.19). Comparisons of antimicrobials received in the prior 2 months showed only cefoxitin (9/70 vs 7/19; P = 0.016) and cefotaxime (4/70 vs 5/19; P = 0.008) to be associated with isolation of resistant organisms. These data suggest that, at our institution, antimicrobial therapy with an extended spectrum cephalosporin is an important risk factor for subsequent acquisition of an organism resistant to third generation cephalosporins.

Cephalosporins↗

PubMed2001

[DNA chip data mining].

DNA chip data routinely contain gene expression levels of thousands of genes and the analysis should be supported by various computational tools. To be brief, the analysis procedure consists of four steps including image scanning, image processing, mathematical interpretation and biological interpretation. In image processing step, we should detect the spots and measure the signals of the spots and the background. In mathematical interpretation step, first of all we should massage the measured signals to make them appropriate for further mathematical analysis. The massaged data could be analyzed by various computational methods especially when the data were generated for multiple samples comparisons. The clustering techniques including hierarchical clustering, k-means clustering, SOTA, SOM are the most popular methods in this step. Various other multivariate statistics and related machine learning techniques are being introduced and applied to DNA chip data analysis recently. And finally the most important step we should tackle is the biological interpretation task. Although the depth of the domain knowledge about the biological situation under which the data were generated is the most important factor to elucidate the biological context, it could be supported by various bioinformatics tools including MEDLINE abstract processing by NLP techniques or genetic network models constructed by Boolean networks algorithms.

Algorithms↗

PubMed2005

A targeted mass spectrometric analysis of phosphatidylinositol phosphate species.

The development of a new mass spectrometric lipid profiling methodology permits the identification of cellular phosphatidylinositol monophosphate/phosphatidylinositol bisphosphate/phosphatidylinositol trisphosphate (PIP/PIP2/PIP3) species that includes the fatty acyl composition. Using electrospray ionization mass spectrometry, we were able to resolve and identify 28 PIP and PIP2 compounds as well as 8 PIP3 compounds from RAW 264.7 or primary murine macrophage cell extracts. Analysis of PIP profiles after agonist stimulation of cells revealed the generation of differential PIP3 species and permitted us to propose a novel means for regulation and specificity in signaling through PIP3. This is the first reported identification of intact, cellular PIP3 by mass spectral analysis. The ability to analyze the fatty acyl chain composition of signaling lipids initiates new venues for investigation of the processes by which specific polyphosphoinositide species mediate.

Animals↗

PubMed1999

Tc-99m DTPA renal scintigraphy using deconvolution analysis with six functional images of the mean time to evaluate acute pyelonephritis.

In 38 children with proved P-fimbriated Escherichia coli acute pyelonephritis, Tc-99m DTPA dynamic renal scintigraphy in the zoom mode using deconvolution analysis was performed, and the results were compared with those of Tc-99m DMSA scans. From the dynamic study, six functional images of the mean time were generated. Each functional image was analyzed separately to search for focal areas of increased mean time within the kidney contour, especially over the kidney parenchyma. Time-activity curves from these areas were generated and analyzed. Tc-99m DMSA scintigraphy showed generalized or focal decreased uptake in 32 (41.8%) kidneys, and deconvolution analysis of Tc-99m DTPA scintigraphy revealed pathologic renographic curves in 58 (77.6%) kidneys. Prolonged whole-kidney and normal renal parenchymal transit times (dilatation without obstruction) were found in 38 (50%) kidneys, whereas prolonged whole-kidney and renal parenchymal transit times (dilatation with obstruction) were observed in 20 (27.6%) kidneys. Separate analysis of each of the six functional images of the mean time showed focal areas of increased mean time in the kidney parenchyma of 11 kidneys. In five cases, time-activity curves from these areas showed a sharp increase of activity on the descending part of the curve, which might reflect the return of urine from the collecting system into kidney cortex (i.e., intrarenal reflux). These results showed that in a urinary tract with acute pyelonephritis, urodynamic changes may lead to obstructive nephropathy and intrarenal reflux. Tc-99m DTPA renal scintigraphy in the zoom mode using deconvolution analysis with six functional images of the mean time has proved to be a valuable method to evaluate acute pyelonephritis, thus allowing dynamic and morphologic analysis of the urinary tract at the same time.

Child↗

PubMed2003

Self-referred whole-body CT imaging: current implications for health care consumers.

PURPOSE: To conduct an empirical analysis of self-referred whole-body computed tomography (CT) and develop a profile of the geographic and demographic distribution of centers, types of services and modalities, costs, and procedures for reporting results. MATERIALS AND METHODS: An analysis was conducted of Web sites for imaging centers accepting self-referred patients identified by two widely used Internet search engines with large indexes. These Web sites were analyzed for geographic location, type of screening center, services, costs, and procedures for managing imaging results. Demographic data were extrapolated for analysis on the basis of center location. Descriptive statistics, such as frequencies, means, SDs, ranges, and CIs, were generated to describe the characteristics of the samples. Data were compared with national norms by using a distribution-free method for calculating a 95% CI (P <.05) for the median. RESULTS: Eighty-eight centers identified with the search methods were widely distributed across the United States, with a concentration on both coasts. Demographic analysis further situated them in areas of the country characterized by a population that consisted largely of European Americans (P <.05) and individuals of higher education (P <.05) and socioeconomic status (P <.05). Forty-seven centers offered whole-body screening; heart and lung examinations were most frequently offered. Procedures for reporting results were highly variable. CONCLUSION: The geographic distribution of the centers suggests target populations of educated health-conscious consumers who can assume high out-of-pocket costs. Guidelines developed from within the profession and further research are needed to ensure that benefits of these services outweigh risks to individuals and the health care system.

Humans↗

PubMed1976

Is there evidence for subclasses of chronic lymphocytic leukemia? A study using numerical classification techniques.

Various clinical and biological parameters were analysed among 95 chronic lymphocytic leukemia patients by two numerical classification techniques in an attempt to identify natural subdivisions in the disease. For each patient, a profile made up of 47 dichotomous variables was constructed and the distance between profiles computed with equal weight for each variable. No specific cluster of patients was identified by these techniques. However limited availability of data for some laboratory tests, particularly concerning the immune system, meant that these results had to be excluded from analysis. The profiles of patients who died from leukemia during a mean follow up period of 4 years apparently do not generate a distinct group from the other profiles in spite of some clustering.

Factor Analysis, Statistical↗

PubMed2001

What is chronic fatigue syndrome? Heterogeneity within an international multicentre study.

OBJECTIVE: We sought to compare the characteristics of patients presenting with chronic fatigue (CF) and related syndromes in eight international centres and to subclassify these subjects based on symptom profiles. The validity of the subclasses was then tested against clinical data. METHOD: Subjects with a clinical diagnosis of CF completed a 119-item self-report questionnaire to provide clinical symptom data and other information such as illness course and functional impairment. Subclasses were generated using a principal components-like analysis followed by latent profile analysis (LPA). RESULTS: 744 subjects returned complete data sets (mean age 40.8 years, mean length of illness 7.9 years, female to male ratio 3:1). Overall, the subjects had a high rate of reporting typical CF symptoms (fatigue, neuropsychological dysfunction, sleep disturbance). Using LPA, two subclasses were generated. Class one (68% sample) was characterized by: younger age, lower female to male ratio; shorter episode duration; less premorbid, current and familial psychiatric morbidity; and, less functional disability. Class two subjects (32%) had features more consistent with a somatoform illness. There was substantial variation in subclass prevalences between the study centres (Class two range 6-48%). CONCLUSIONS: Criteria-based approaches to the diagnosis of CF and related syndromes do not select a homogeneous patient group. While substratification of patients is essential for further aetiological and treatment research, the basis for allocating such subcategories remains controversial.

Adult↗

PubMed1976

Genetic analysis of the centromeric heterochromatin of chromosome 2 of Drosophila melanogaster: deficiency mapping of EMS-induced lethal complementation groups.

Until recently, little was known of the genetic constitution of the heterochromatic segments of the major autosomes of Drosophila melanogaster. Our previous report described the genetic dissection of the proximal, heterochromatic region of chromosome 2 of Drosophila melanogaster by means of a series of overlapping deficiencies generated by the detachment of compound second autosomes (HILLIKER and HOLM 1975). Analysis of these deficiencies by inter se complementation, pseudo-dominance tests with proximal mutations and allelism tests with known deficiencies provided evidence for the existence of at least two loci between the centromere and the light locus in 2L and one locus in 2R between the rolled locus and the centromere. These data in conjunction with cytological observations demonstrated that light and rolled and three loci lying between them are located within the proximal heterochromatin of the second chromosome. The present report describes the further analysis of this region through the induction with ethyl methanesulphonate (EMS) of recessive lethals allelic to the 2L and 2R proximal deficiencies associated with the detachment products. Analysis of the 118 EMS-induced recessive lethals and visible mutations recovered provided evidence for seven loci in the 2L heterochromatin and six loci in the 2R heterochromatin, with multiple alleles being obtained for most sites. Of these loci, one in 2L and two in 2R fall near the heterochromatic-euchromatic junctions of 2L and 2R respectively. None of the 113 EMS lethals behaved as a deficiency, implying that the heterochromatic loci uncovered in this study represent nonrepetitive cistrons. Thus functional genetic loci are found in heterochromatin, albeit at a very low density relative to euchromatin.

Alleles↗

PubMed1996

Themes relating to sexuality that emerged from a discourse analysis of the Nursing Times during 1980-1990.

The intention of this study was to develop insight into how the concept of human sexuality has been addressed within a popular nursing medium, namely the publication Nursing Times, during the decade 1980-1990. The study begins by clarifying discourse analysis and its role in the social construction of language. Exploration of the use of metaphors within nursing text is made to highlight the ability to convey multiple meaning and ideology within nursing practice. The 86 text papers generated during this decade were subjected to a process of qualitative data analysis entitled 'Framework'. The emerging themes from this process were used to inform a discussion of the ideological and practice relationships that exist between nursing and human sexuality.

Cultural Characteristics↗

PubMed2003

The measurement of adenosine and estrogen receptor expression in rat brains following ovariectomy using quantitative PCR analysis.

In our laboratory we have developed a quantitative-polymerase chain reaction (Q-PCR) strategy to examine the differential expression of adenosine receptor (ADOR), A(1), A(2A), A(2B) and A(3), and estrogen receptors (ER) alpha and beta. Brain and uterine mRNA were first used to optimise specific amplification conditions prior to SYBR Green I real time analysis of receptor subtype expression. SYBR Green I provided a convenient and sensitive means of examining specific PCR amplification product in real time, and allowed the generation of standard curves from which relative receptor abundance could be determined. Real time Q-PCR analysis was then performed, to examine changes in receptor expression levels in brains of adult female Wistar rats 3-month post ovariectomy. Comparison with sham-operated age-matched control rats demonstrated both comparative and absolute-copy number changes in receptor levels. Evaluation of both analytical methods investigated 18S rRNA as an internal reference for comparative gene expression analysis in the brain. The results of this study revealed preferential repression of ADORA(2A) (>4-fold down) and consistent (>2-fold) down-regulation of ADORA(1), ADORA(3), and ER-beta, following ovariectomy. No change was found in ADORA(2B) or ER-alpha. Analysis of absolute copy number in this study revealed a correlation between receptor expression in response to ovariectomy, and relative receptor subtype abundance in the brain.

Animals↗

PubMed2005

Automated quantitative analysis of E-cadherin expression in lymph node metastases is predictive of survival in invasive ductal breast cancer.

PURPOSE: The tumor suppressor adhesion molecule E-cadherin is believed to have an anti-invasive role in breast cancer. Lymph node involvement is the best prognostic marker known, yet there is variability in outcome among node-positive patients. We investigated the relationship between E-cadherin expression in primary invasive ductal tumors and corresponding nodal metastases, and determined the prognostic value of E-cadherin expression in node-positive breast cancer. EXPERIMENTAL DESIGN: Membrane E-cadherin expression was studied by immunohistochemical staining of tissue microarrays with fluorescent-labeled antibodies. An objective method of automated quantitative analysis (AQUA) was used. AQUA uses cytokeratin to define pixels as breast cancer (tumor mask) within the array spot, and measures E-cadherin expression using a Cy5-conjugated antibody within the mask. RESULTS: We employed a tissue microarray containing 207 primary and matched nodal metastases suitable for AQUA analysis. There was no significant difference in mean staining intensity between the primary and nodal specimens (P = 0.8). A scattergram was generated which identified a subset of patients (25%) with high E-cadherin expression in nodal metastases, and this top quartile had improved survival (P = 0.028). On univariate analysis, increased E-cadherin expression in nodal metastases was strongly associated with improved survival (P = 0.007), whereas expression in primary tumors was not (P = 0.13). On multivariate analysis, nodal E-cadherin expression retained its independent association with survival, as did tumor size and HER2/neu status. CONCLUSIONS: Strong E-cadherin expression in lymph node metastases was highly predictive of improved survival. This suggests that expression of adhesion molecules at metastatic sites portends less aggressive tumor behavior.

Breast Neoplasms↗

PubMed2003

The distribution of active force generators controls mitotic spindle position.

During unequal cell divisions a mitotic spindle is eccentrically positioned before cell cleavage. To determine the basis of the net force imbalance that causes spindle displacement in one-cell Caenorhabditis elegans embryos, we fragmented centrosomes with an ultraviolet laser. Analysis of the mean and variance of fragment speeds suggests that the force imbalance is due to a larger number of force generators pulling on astral microtubules of the posterior aster relative to the anterior aster. Moreover, activation of heterotrimeric guanine nucleotide- binding protein (Gprotein) alpha subunits is required to generate these astral forces.

Anaphase↗

PubMed2004

Three-dimensional assessment of morphologic changes of the maxilla: a comparison of 2 kinds of palatal expanders.

Previous studies of the morphologic changes of the maxilla after palatal expansion have used 2-dimensional methodologies. In the present study, we used a 3-dimensional surface laser scanning technique and computerized cast analysis, in addition to analysis of anteroposterior cephalograms, to assess the morphologic changes of the palate by 2 kinds of expanders: tissue borne (Haas; n = 9) and tooth borne (Hyrax; n = 10). Cast analysis demonstrated that, although all patients started treatment with similar malocclusion, treatment outcomes were different depending on the appliance used. Both appliances generated maxillary expansion (ie, improved mean surface area, mean intermolar linear distance, and mean perimeter) (P <.05). However, the appliances performed differently to achieve the final expansion. Haas appliances demonstrated a greater orthopedic movement (ie, improvement of the mean interpalatal distance) (P <.05), and Hyrax appliances demonstrated dentoalveolar expansion by increasing the mean palatal angulation of the alveolus (P <.05). Anteroposterior cephalometric analysis showed that both appliances increased mean maxillary width and mean intermolar distance significantly (P <.05). On the other hand, differences in nasal cavity width and upper incisal apex distance were not statistically significant (P >.05). This new 3-dimensional methodology proved useful for comparing treatment outcomes by evaluating the morphologic changes induced by palatal expansion and generated a better visualization of these outcomes.

Adolescent↗

PubMed1977

A difference in the composition of bronchial mucus between smokers and non-smokers.

The ratio of the amount of sulphated to sialic acid mucin (Su/Si) in the mucous glands of the human tracheobronchial tree has been investigated in seven smokers and seven non-smokers. The two mucins were studied in histological sections stained by the high iron diamine/Alcian blue pH 2-5 sequence and assessed by a point-counting method. Su/Si was greater in the smokers than in the non-smokers, who were almost completely distinguished by this ratio. A decrease in the ratio with each generation of branching from the trachea down the inferior lingular bronchial segmental pathway was seen in both the smoking and non-smoking groups. Analysis of the logarithm of Su/Si showed the smoking group means to be 2-3 times that of the non-smokers at each generation, and over both groups the average decrease down successive generations was given by a factor of 0-9.

Aged↗

PubMed2001

Tissue segmentation-assisted analysis of fMRI for human motor response: an approach combining artificial neural network and fuzzy C means.

The authors have developed an automated algorithm for segmentation of magnetic resonance images (MRI) of the human brain. They investigated the quantitative analysis of tissue-specific human motor response through an approach combining gradient echo functional MRI and automated segmentation analysis. Fifteen healthy volunteers, placed in a 1.5 T clinical MR imager, performed a self-paced finger opposition throughout the activation periods. T1-weighted images (WI), T2WI, and proton density WI were acquired for segmentation analysis. Single-slice axial T2* fast low-angle shot (FLASH) images were obtained during the functional study. Pixelwise cross-correlation analysis was performed to obtain an activation map. A cascaded algorithm, combining Kohonen feature maps and fuzzy C means, was applied for segmentation. After processing, masks for gray matter, white matter, small vessels, and large vessels were generated. Tissue-specific analysis showed a signal change rate of 4.53% in gray matter, 2.98% in white matter, 5.79% in small vessels, and 7.24% in large vessels. Different temporal patterns as well as different levels of activation were identified in the functional response from various types of tissue. High correlation exists between cortical gray matter and subcortical white matter (r = 0.957), while the vessel behaves somewhat different temporally. The cortical gray matter fits best to the assumed input function (r = 0.957) followed by subcortical white matter (r = 0.829) and vessels (r = 0.726). The automated algorithm of tissue-specific analysis thus can assist functional MRI studies with different modalities of response in different brain regions.

Adult↗

PubMed1993

Flow quantitation by radio frequency analysis of contrast echocardiography.

Contrast echocardiography has the potential for measuring cardiac output and regional blood flow. However, accurate quantitation is limited both by the use of non-standard contrast agents and by the electronic signal distortion inherent to the echocardiographic instruments. Thus, the aim of this study is to quantify flow by combining a stable contrast agent and a modified echo equipment, able to sample the radio frequency (RF) signal from a region of interest (ROI) in the echo image. The contrast agent SHU-454 (0.8 ml) was bolus injected into an in vitro calf vein, at 23 flow rates (ranging from 376 to 3620 ml/min) but constant volume and pressure. The ROI was placed in the centre of the vein, the RF signal was processed in real time and transferred to a personal computer to generate time-intensity curves. In the absence of recirculation, contrast washout slope and mean transit time (MTT) of curves (1.11-8.52 seconds) yielded excellent correlations with flow: r = 0.93 and 0.95, respectively. To compare the accuracy of RF analysis with that of conventional image processing as to flow quantitation, conventional images were collected in the same flow model by two different scanners: a) the mechanical sector scanner used for RF analysis, and b) a conventional electronic sector scanner. These images were digitized off-line, mean videodensity inside an identical ROI was measured and time-intensity curves were built. MTT by RF was shorter than by videodensitometric analysis of the images generated by the same scanner (p < 0.001). In contrast, MTT by RF was longer than by the conventional scanner (p < 0.001). Significant differences in MTT were also found with changes in the gain setting controls of the conventional scanner. To study the stability of the contrast effect, 6 contrast injections (20 ml) were performed at a constant flow rate during recirculation: the spontaneous decay in RF signal intensity (t1/2 = 64 +/- 8 seconds) was too long to affect MTT significantly. In conclusion, the combination of a stable contrast agent and a modified echocardiographic instrument provides accurate quantitation of flow in an in vitro model; RF analysis is more accurate than conventional processing as to flow quantitation by contrast echocardiography.

Animals↗

PubMed2001

Influence of the unpacked section on the chromatographic performance of duplex strong anion-exchange columns in capillary electrochromatography.

This work describes initial investigations of strong anion-exchange (SAX) packing materials for capillary electrochromatography (CEC). The use of SAX phases in CEC is theoretically appealing for the analysis of negatively charged species. The reversed direction of the electroosmotic flow (EOF) generated by SAX phases (in comparison to reversed phases and strong cation-exchange phases) means that negative species can migrate with the EOF, not against it, hence the analysis times, of such species should be decreased and efficiencies improved. Duplex CEC columns (the standard for instruments using UV detection) consist of a packed and an unpacked section. Using common reversed-phase packing materials the direction of the EOF in both sections is co-linear, however when normal fused-silica capillaries are packed with SAX material the direction of the EOF in the two sections oppose one another. It has been shown, using conventional duplex CEC columns and fully packed CEC-MS columns that the opposing direction of EOF causes a massive degradation in column performance. Consequentially, it is demonstrated that if the EOF in the open section of the duplex SAX column can be controlled via pH or capillary derivatisation then good, reproducible CEC can be performed on anionic species using SAX packed CEC columns.

Anion Exchange Resins↗