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PubMedDate not supplied

Screening of protein-ligand interactions by affinity chromatography.

This paper examines affinity chromatography (AC) as an alternative tool for the determination of protein-ligand interactions for the particular case in which the ligand is the same protein. The methodology is less labor-intensive and more sample-efficient than traditional methods used to measure the second virial coefficient (B(22)), a parameter commonly used to evaluate protein-protein interactions. The chromatographic capacity factor (k') was studied for lysozyme and equine serum albumin for a wide range of experimental solution conditions such as crystallizing agent concentration, protein concentration and pH. Parallel experiments using AC to determine k' and static light scattering (SLS) to determine B(22) showed that the two parameters were highly correlated. Two different column volumes ( approximately 1 and approximately 0.1 mL) were tested and gave essentially the same values for k', showing the feasibility of miniaturization.

Chromatography, Affinity↗
PubMed2006

Mayisha II: pilot of a community-based survey of sexual attitudes and lifestyles and anonymous HIV testing within African communities in London.

The pilot aim was to assess the feasibility and acceptability of undertaking anonymous HIV testing using oral fluid samples as part of a community-based survey of sexual attitudes and lifestyles of black African communities in London. The three components of the study were administered in various venues across London: (1) a cross-sectional self-completion anonymous questionnaire survey, (2) an optional oral fluid sample for anonymous HIV testing and (3) a nested in-depth interview study in a sub-set of respondents. A total of 114 black African men and women were recruited. A large number of African countries were represented among respondents from newly-migrant and well-established communities. The response rate to the oral fluid sample was high at 82% and all samples collected were of sufficient quality to be tested for HIV. In-depth interviews with respondents revealed positive views and experiences about participating in the study whilst understanding of the questionnaire was good. We therefore conclude that anonymous HIV testing as part of a community-based survey is feasible and acceptable, whilst a set of recommendations was produced to refine the survey methodology and questionnaire. Participatory research methods are essential for achieving successful community-based surveys among black Africans in Britain.

Adult↗
PubMed2000

Reconstruction of MR images from data acquired on a general nonregular grid by pseudoinverse calculation.

A minimum-norm least-squares image-reconstruction method for the reconstruction of magnetic resonance images from non-Cartesian sampled data is proposed. The method is based on a general formalism for continuous-to-discrete mapping and pseudoinverse calculation. It does not involve any regridding or interpolation of the data and therefore the methodology differs fundamentally from existing regridding-based methods. Moreover, the method uses a continuous representation of objects in the image domain instead of a discretized representation. Simulations and experiments show the possibilities of the method in both radial and spiral imaging. Simulations revealed that minimum-norm least-squares image reconstruction can result in a drastic decrease of artifacts compared with regridding-based reconstruction. Besides, both in vivo and phantom experiments showed that minimum-norm least-squares image reconstruction leads to contrast improvement and increased signal-to-noise ratio compared with image reconstruction based on regridding. As an appendix, an analytical calculation of the raw data corresponding to the well-known Shepp and Logan software head phantom is presented.

Humans↗
PubMedDate not supplied

Talking circles: Northern Plains tribes American Indian women's views of cancer as a health issue.

OBJECTIVE: The purpose of this research was to understand the cultural meanings of cancer among American Indian women from Northern Plains tribes living in western South Dakota and their experiential view of breast and cervical cancer screening. DESIGN AND SAMPLE: Using an exploratory design, a purposive sample of 28 women, 35-75 years of age, were recruited into three Talking Circles. MEASUREMENT: Talking Circle and focus group methodology, combined with Affonso's Focus Groups Analytic Schema, were used to generate contextual data sets including thematic findings. RESULTS: Ten themes emerged indicating interrelationships between cultural traditions and health structures of care. The themes provided a unique perspective for conceptualizing women's experiences with breast and cervical cancer screening. CONCLUSIONS: Incorporating women's cultural experiences into screening services is necessary to address clinical and policy challenges for reducing breast and cervical cancer mortality among American Indian women. Findings from this research will be used to guide a future study investigating breast-screening patterns related to mammography adherence and development of interventions specific to American Indian women.

Adult↗
PubMed1994

Detection efficacy of soluble HLA-A, B antigens using 1D-IEF.

Soluble HLA class I alloantigens (sHLA class I) can be typed according to their isoelectric points (IEP) after immunoprecipitation by w6/32 monoclonal antibody (mAb) coupled to immunomagnetic beads and focusing. In order to prove the large scale efficacy of this methodology, EDTA-plasma samples from 344 probands HLA-A, B typed by serology were analysed by one-dimensional isoelectric focusing and HLA class I specific Westernblot (1D-IEF). In addition, detergent solubilized HLA class I membrane molecules from approximately one half of the probands were studied too. Soluble HLA-A24,B7,B18,B62 antigens were identified in nearly all experiments, whereas A28, B13, and B51 could be detected in about 50%. A third group of HLA antigens (A26, B8, B44) could be visualized rarely. The difficulties of detection might be due to the different affinity of mAb w6/32 to certain sHLA class I gene products or to variable amounts of sHLA class I in the plasma specimens. Some modifications of the antigen capture technique have already led to a slightly better degree of antigen recognition in 25 probands tested. Thus, HLA-A, B typing using sHLA molecules and 1D-IEF in the assay format presented does not yet seem to be a definitive alternative for HLA class I serology or biochemistry of membrane-bound HLA class I molecules but it should be a promising technique if no cells are available or donor-derived sHLA allotypes are to be monitored after HLA mismatched organ transplantation.

Antibodies, Monoclonal↗
PubMed1997

Oral heath status of 12-year-old children in Nepal in 1994.

A survey of twelve-year-old Nepalese children was undertaken in 1994 according to the WHO pathfinder methodology and examination criteria. The study sample was drawn from randomly selected schools within the capital city, and two randomly selected urban settings, together with children drawn from schools in four randomly selected villages within rural Nepal. Three hundred and sixty children were examined. Drinking water samples were obtained from all sources at each examination site and subsequently analysed for fluoride content. The overall caries experience in the country was found to be very low or low. Analysis of drinking water samples revealed that with the exception of one town in the south of the country, all sites had low fluoride levels.

Cariostatic Agents↗
PubMed1998

Trichloroethene levels in human blood and exhaled breath from controlled inhalation exposure.

The organic constituents of exhaled human breath are representative of bloodborne concentrations through gas exchange in the blood/breath interface in the lungs. The presence of specific compounds can be an indicator of recent exposure or represent a biological response of the subject. For volatile organic compounds, sampling and analysis of breath is preferred to direct measurement from blood samples because breath collection is noninvasive, potentially infectious waste is avoided, the sample supply is essentially limitless, and the measurement of gas-phase analytes is much simpler in a gas matrix rather than in a complex biological tissue such as blood. However, to assess the distribution of a contaminant in the body requires a reasonable estimate of the blood level. We have investigated the use of noninvasive breath measurements as a surrogate for blood measurements for (high) occupational levels of trichloroethene in a controlled exposure experiment. Subjects were placed in an exposure chamber for 24 hr; they were exposed to 100 parts per million by volume trichloroethene for the initial 4 hr and to purified air for the remaining 20 hr. Matched breath and blood samples were collected periodically during the experiment. We modeled the resulting concentration data with respect to their time course and assessed the blood/breath relationship during the exposure (uptake) period and during the postexposure (elimination) period. Estimates for peak blood levels, compartmental distribution, and time constants were calculated from breath data and compared to direct blood measurements to assess the validity of the breath measurement methodology. Blood/breath partition coefficients were studied during both uptake and elimination. At equilibrium conditions at the end of the exposure, we could predict actual blood levels using breath elimination curve calculations and a literature value partition coefficient with a mean ratio of calculated:measured of 0.98 and standard error (SE) = 0.12 across all subjects. blood/breath comparisons at equilibrium resulted in calculated in vivo partition coefficients with a mean of 10.8 and SE = 0.60 across all subjects and experiments and 9.69 with SE = 0.93 for elimination-only experiments. We found that about 78% of trichloroethene entering the body during inhalation exposure is metabolized, stored, or excreted through routes other than exhalation.

Administration, Inhalation↗
PubMedDate not supplied

Is it possible with an immunophenotypic study to foresee the oncologic risk of epithelial gastric dysplasia?

BACKGROUND/AIMS: Epithelial gastric dysplasia is considered the only true marker of gastric cancer. High-grade dysplasia is a surgical therapy needing lesion and low-grade dysplasia is considered a lesion with a low oncologic risk. The aim of this experience was to verify whether there are any immunohistochemical evaluations which may enable one to foresee more precisely the evolution of epithelial gastric dysplasia. METHODOLOGY: Immunophenotypic evaluation was effected in 70 cases of low-grade dysplasia (41 males, average age: 57.4) and in 50 cases of high-grade dysplasia (31 males, average age: 58). These cases were retrospectively selected and the studied samples are represented by gastric biopsies obtained in the course of endoscopy performed for dyspepsia. Epithelial gastric dysplasia diagnosis was done according to Goldstein and Lewin and the clinical subdivision was effected using the criteria of Rugge et al. Four antigens were studied using Abs against pepsinogen C, gastric foveolar M1, intestinal CAR-5 and pancreatic DU-PAN-2 Ags. RESULTS: Epithelial gastric dysplasia is characterized by a progressive reduction of gastric markers with a progressive expression of enteropancreatic antigens. Low-grade dysplasia is characterized by a frequent gastro-enteropancreatic coexpression, and high-grade dysplasia by a frequent enteropancreatic coexpression or by no markers expression. Low-grade dysplasia with greater enteropancreatic markers progresses frequently towards gastric cancer; high-grade dysplasia with enteropancreatic markers only is associated/progresses to gastric cancer, while high-grade dysplasia with gastric markers or gastric-enteropancreatic markers is included in the group with persistent or regressed cases. CONCLUSIONS: If confirmed in further studies, such results could modify the evaluation of epithelial gastric dysplasia, not only in terms of histochemical techniques, but also of immunohistochemical techniques.

Disease Progression↗
PubMed1980

Biomedical microanalysis--putting it to work now in diagnostic pathology.

Based on a review of seven years' experience with microanalysis in human pathology, the emphasis of this keynote paper is that currently available microanalytic instrumentation and methodology are of great use diagnostically. The appropriate diagnostic questions which must be posed for microanalysis center around those seeking the cause of the disease (etiologic diagnosis). The preventive and forensic aspects of etiologic diagnosis are stressed. Pathologists analyse not only tissues but also material samples. The backscattered electron (BSE) image with compositional contrast has been essential in making efficient diagnostic use of microanalysis in the scanning electron microscope (SEM). From the 454 specimens seen in the four years 1976-1979, examples are presented to illustrate several aspects of microanalysis: e.g., documentation of the identity and source of toxic dust in lungs; identification of particulate materials in liver, kidney, salivary glands, lymph nodes, etc.; problems of contamination of specimens; use of high vs low magnification analysis; relative volume of tissue sampled using thick (5 micrometer) vs thin (100nm) sections; time required for analysis; and use of fresh frozen, cryo-sectioned tissue for analysis of soluble materials. For practical diagnostic microanalysis, SEM with BSE and x-ray microanalysis of 5 micrometer thick tissue sections at present seems to be the most efficient procedure.

Electron Probe Microanalysis↗
PubMed1998

[Process and outcome quality in inpatient care: a contribution to evaluation and quality assurance in child and adolescent psychiatry].

In a prospective study individual symptoms, diagnosis, treatment and goal-attainment were assessed in the total sample of in-patients during a one year period. As a contribution to quality-assurance we investigated the conditions under which the provided treatment can be helpful for our patients. The study focused on the quality of treatment and the documentation of diagnostic and treatment services provided. The results show that methodologies used in evaluation studies have to adapt to the subjective experience of individual disorders and the therefore resulting distress children and their families suffer from. Improvements and the operationalization of outcome-quality have also to be measured by these parameters.

Child↗
PubMed2002

Research methodology for studies of prayer and distant healing.

The double-blind randomized clinical trial is the gold standard for trials of prayer and distant healing. Adequate blinding and randomization procedures should be followed and documented. The intervention must be well defined (include frequency, amount of time and training and/or experience level of healers). Subjects should have risks and benefits of study participation explained to them and sign informed consent before enrollment. Populations should be homogeneous. Consider stratification for smaller samples. Baseline information, including psychological status, beliefs about prayer and healing and other sources of prayer and healing, should be collected from subjects in clinical trials. This should be examined as part of the final data analysis for contribution to outcomes. Objectively measurable outcomes with adequate variability should be chosen. Subject study participation activities such as clinical interviews, traveling to special sites. journaling or meditation should be minimized to avoid washing out a small effect. In clinical trials subjects should be asked if they believed they were in the treatment group and this information should be entered as a co-variate for data analysis. Healers/prayers should be treated in a collegial and respectful way. Their healing efforts (time. location, method) should be documented in a log and they should be periodically contacted and encouraged by experimenters if the study' is taking place over an extended period of time. Observational and outcomes research can add an important dimension to healing research. Qualitative studies may also make an important contribution and help guide development of future controlled trials.

Attitude to Health↗
PubMed1997

Removal of catheter distortion in multiple indicator dilution studies: a deconvolution-based method and case studies on glucose blood-tissue exchange.

The study of blood-tissue exchange by the multiple indicator dilution technique often needs frequent sampling in the blood of the indicator dilution curves (IDC). Usually, this requires the use of a catheter supported by a pump. This causes a distortion in the IDC, which must be removed for proper interpretation of the data. A deconvolution-based methodology to remove IDC distortion is presented. First, the catheter impulse response is modelled by means of data obtained from a suitable experiment. Then the reconstruction of the blood IDC is tackled by a new nonparametric deconvolution algorithm, which provides (quasi) time-continuous signals and exploits statistically based criteria for the choice of the regularisation parameter. The methodology is applied to the removal of catheter distortion in studies of glucose blood-tissue exchange in the human forearm and myocardium.

Blood Glucose↗
PubMed2026

The clinical promise of mass spectrometry-based single-cell proteomics: from bedside to bench.

INTRODUCTION: Single-cell proteomics (SCP) is entering into a transformative phase, moving beyond technically demanding benchmarking studies toward robust and reproducible workflows capable of quantifying thousands of proteins per cell. These advances highlight SCP's potential to address clinically relevant questions by resolving cellular and pathological heterogeneity that remains obscured in bulk proteomics. AREAS COVERED: This review discusses current advances, challenges, and clinical applications of SCP based on literature identified through searches in major scientific databases. Many clinically relevant samples remain underexplored in SCP studies, in part because their application requires careful evaluation of pre-analytical variables that can strongly influence proteomic readouts. Current SCP methodologies vary according to sample type, experimental conditions, and available resources. Compared with single-cell RNA sequencing, SCP remains limited in cellular throughput, making it challenging to define optimal sample sizes and to reliably detect both abundant and rare cell populations. These limitations also make dataset integration difficult, as reduced cellular coverage and sampling depth increase data sparsity. Moreover, implementing quality control strategies across sequential SCP experiments is essential to ensure data robustness, comparability, and accurate biological interpretation. EXPERT OPINION: Applying SCP to clinical samples advances our understanding of biological complexity and holds potential to drive progress in translational and precision medicine.

Humans↗
PubMedDate not supplied

An improved methodology for advancing nursing research: factorial surveys.

Clinical judgments and decisions are an integral component of nurse work and nurses are increasingly being challenged to account for their judgments and decisions. Nursing research is needed to help explain judgment and decision making in nursing, but most research in this area is almost exclusively characterized by descriptive studies. This article describes the use of the factorial survey method, which combines the explanatory power of a factorial experiment with the benefits of a sample survey. This hybrid technique is an excellent method for studying judgments and decisions across settings, roles, disciplines, and countries. This article outlines the steps of the method and demonstrates its applicability with an exemplar from a study across nurses from 3 countries.

Decision Making↗
PubMed1996

Estimation of the C-cell numbers in rat thyroid glands using the optical fractionator.

We estimated the total number of calcitonin-immunoreactive C-cells in rat thyroid gland using the optical fractionator, the unbiased stereological method for estimation of numbers. It was necessary first to use a fixative composed of formalin, acetic acid, and ethanol to distinctly visualize the C-cells. The 40-microm-thick sections had to adhere to chromalum-gelatin-coated Superfrost Plus glass slides, and the immunostaining technique had to stain the C-cells evenly throughout the whole sections. Because the C-cells were irregularly distributed in the thyroid tissues, their counting required screening of about 500 fields per lobe, but the number of C-cells counted need not be high, about 90 per lobe. We estimated that rats have 185,000 +/- 42,000 C-cells (mean +/- SD; n - 7). The C-cell population did not differ significantly between the two lobes of a given rat, but it varied markedly among rats. The biological differences among the animals contributed 83% to the observed variability, whereas the methodological uncertainty contributed 17%. The serum levels of calcitonin and calcium were not closely correlated to the C-cell numbers. Our results indicate that variability in C-cell experiments can be reduced most effectively by increasing the number of animals used. However, the similar C-cell frequency found in the two thyroid lobes of each rat allows the use of one uniformly sampled lobe for quantification and the other lobe for further analysis.

Animals↗
PubMed2003

Clinically validated benchmarking of normalisation techniques for two-colour oligonucleotide spotted microarray slides.

Acquisition of microarray data is prone to systematic errors. A correction, called normalisation, must be applied to the data before further analysis is performed. With many normalisation techniques published and in use, the best way of executing this correction remains an open question. In this study, a variety of single-slide normalisation techniques, and different parameter settings for these techniques, were compared over many replicated microarray experiments. Different normalisation techniques were assessed through the distribution of the standard deviation of replicates from one biological sample across different slides. It is shown that local normalisation outperformed global normalisation, and intensity-based 'LOWESS' outperformed trimmed mean and median normalisation techniques. Overall, the top performing normalisation technique was a print-tip-based LOWESS with zero robust iterations. Lastly, we validated this evaluation methodology by examining the ability to predict oestrogen receptor-positive and -negative breast cancer samples with data that had been normalised using different techniques.

Algorithms↗