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Sample preparation and mass-spectrometric characterization of crystal-derived protein samples.

Mass spectrometry is often used to ascertain the accurate mass of purified protein samples prior to crystallization screening. However, in many cases data regarding the form of the protein crystallizing can also be useful, as this may differ from the original sample. Development of a simple method for the preparation and mass spectrometry of crystal-derived protein samples is described. The method is exemplified by the determination of the phosphorylation state of protein in a crystal derived from a mixture of phosphorylated and unphosphorylated protein.

Chromatography, High Pressure Liquid↗

Views of female breast cancer patients who donated biologic samples regarding storage and use of samples for genetic research.

Although social and ethical issues related to the storage and use of biologic specimens for genetic research have been discussed extensively in the medical literature, few empiric data exist describing patients' views. This qualitative study explored the views of 26 female breast cancer patients who had consented to donate blood or tissue samples for breast cancer research. Participants generally did not expect personal benefits from research and had few unprompted concerns. Few participants had concerns about use of samples for studies not planned at the time of consent. Some participants did express concerns about insurance or employment discrimination, while others believed that current privacy protections might actually slow breast cancer research. Participants were generally more interested in receiving individual genetic test results from research studies than aggregate results. Most participants did not want individual results of uncertain clinical significance, although others believed that they should be able to receive such information. These data examined the range of participants' views regarding the storage and use of biologic samples. Further research with different and diverse patient populations is critical to establishing an appropriate balance between protecting the rights of human subjects in genetic research and allowing research to progress.

Breast Neoplasms↗

Fetoscopy guided by real-time ultrasound for pure fetal blood samples, fetal skin samples, and examination of the fetus in utero.

Techniques for sampling pure fetal blood, fetal skin and for fetal examination by fetoscopy are described in detail after experience gained in 151 diagnostic fetoscopies on 145 patients. Of particular importance were a real-time scanner and a particle size analyser. The region of insertion of the umbilical cord into the placenta was the optimum site for obtaining pure fetal blood, and this was achieved in 136 out of 143 patients (95 per cent) sampled at 18 to 23 weeks gestation. This made maternal blood transfusion before prenatal diagnosis of haemoglobinopathies unnecessary. An anterior placenta rarely prevented successful fetoscopy, and often made fetal blood sampling easier. Four fetal losses (3.7 per cent) were judged to be due to fetoscopy.

Blood Specimen Collection↗

New technique for quantitative bacteriological sampling of wounds by velvet pads: clinical sampling trial.

A new surface sampling method, the velvet pad rinse technique, was compared with the velvet pad imprint method, in a randomized bacteriological sampling trial, using surgical wounds to evaluate quantitative results. The efficiency of bacterial recovery was increased 20-fold by the new technique, and the improvement was ascribed in particular to the introduction of a procedure of rinsing the velvet pad after sampling.

Bacteria↗

Influence of volume of sample processed on detection of Chlamydia trachomatis in urogenital samples by PCR.

In the present study, it was demonstrated that the sensitivity of the PCR for the detection of Chlamydia trachomatis is influenced by the volume of the clinical sample which is processed in the PCR. An adequate sensitivity for PCR was established by processing at least 4%, i.e., 80 microliters, of the clinical sample volume per PCR. By using this preparation procedure, 1,110 clinical samples were evaluated by PCR and by cell culture, and results were compared. After discordant analysis, cell culture resulted in a sensitivity of 79.1% and PCR resulted in a sensitivity of 92.7%. Furthermore, it was shown that treatment with antibiotics immediately resulted in negative cell culture results but that PCR could give positive results up to 2 weeks posttreatment.

Cervix Uteri↗

The Florence city sample: dietary and life-style habits of a representative sample of adult residents. a comparison with the EPIC-Florence volunteers.

A representative sample of the general population residing in the city of Florence was invited to participate in the local section of the EPIC study with two major aims: i) to carry out a population-based survey on dietary and life-style habits in this urban area of Tuscany, Central Italy; ii) to compare these results with a large series of EPIC volunteers residing in the same municipality in order to evaluate the differences between the two groups. A random sample of 500 residents (250 women) aged 40-64 years, was invited to participate in the study; 362/500 (72.4%) accepted and followed the EPIC protocol. The distribution of selected individual characteristics (including measured weight and height) showed a high prevalence of being overweight in men (52.2%) and obesity in both sexes (17.4% in men and 12.5% in women). A dietary pattern characterized by a high consumption of red meat, processed meats, olive oil and wine emerged in both sexes; the consumption of vegetables and fresh fruit was approximately 200 and 300 g/day, respectively. The estimated mean intakes of macronutrients reflected this pattern, with a high mean intake of total fat and protein. The mean contribution to total caloric intake provided by fat was 30.9% and 33.6% in these randomly sampled men and women, respectively. The results were compared with those of 9,123 Florence residents aged 40-64 years and enrolled as EPIC volunteers. Current smokers and less educated subjects were less represented among male volunteers, who, in general, showed a healthier dietary pattern (more fresh fruit and less spirits). Female volunteers were taller and heavier and consumed more fresh fruit but also more beef and less carbohydrates. Other statistically significant differences emerged, but the absolute values of these differences were usually modest and the two groups appeared remarkably similar. Overall, our results suggest that the large EPIC-Florence cohort was not strictly selected and showed a total caloric intake and a range of dietary variability similar to that of the general population of the same area.

Adult↗

The factor analytic structure of the Roberts Apperception Test for Children: a comparison of the standardization sample with a sample of chronically ill children.

A confirmatory principal component factor analysis of the Roberts Apperception Test for Children was conducted using the standardization sample and a sample of chronically ill children. An interpretation of three- and four-factor solutions identified the three-factor solution as superior to the four-factor solution as measured by chi-square goodness of fit and coefficients of convergence. A cluster analysis using Ward's minimum variance method was calculated to determine the typical profiles that best describe the chronically ill sample. Results of this analysis reveal two distinct profiles that differ primarily on the level of adaptive psychological functioning.

Adaptation, Psychological↗

Cerebrospinal fluid sampling from guineapigs: sample volume--related changes in protein concentration in control animals and animals in the relapsing phase of chronic relapsing experimental allergic encephalomyelitis.

Cerebrospinal fluid (CSF) was removed from guineapigs by puncture of the cisterna magna and the total sample volume of 200-360 microl divided into 40 microl aliquots. After determination of albumin and IgG in these CSF aliquots it was found that successive samples gave different results. In general, up to 100 microl CSF could be removed before the protein concentration began to increase. In animals with chronic relapsing experimental allergic encephalomyelitis (CR-EAE) the rise in albumin concentration was accompanied by a corresponding fall in the number of white cells in later samples.

Albumins↗

Blood sampled in rats from right ventricle may not always be truly representative of a mixed venous sample.

Blood samples from the right ventricle (RV) in rats are usually assumed to be representative of mixed venous blood. However, results presented here suggest that this assumption may not be true in all experimental circumstances. Nineteen male Wistar rats were anaesthetized with urethane and mechanically ventilated. The six gases used in the multiple inert gas elimination technique (MIGET) were administered continuously and samples of mixed expired air and blood from the left carotid artery and RV were simultaneously withdrawn. While inert gas concentrations in arterial blood and mixed expired air were almost homogeneous, those obtained from RV blood showed a high variability, specially evident for the less soluble gases in blood. As inert gases are cleared in the lungs according to their solubility in blood and they are only replaced through the lower systemic circulation, higher or lower concentrations found in RV samples than those expected suggests a preferential collection of blood from the lower or upper systemic circulation, respectively.

Animals↗

Determining sample differences in a sample series of complex liquid chromatography-diode array detector data using chemometrics.

In analytical laboratories, one often has to deal with sample series that have minor differences between them. For example, different batches of the same material may cause manufacturing problems, and quality control is an important issue. Another example is decomposition studies, where changes may or may not occur in a sample. To extract the differences between such highly related samples from LC-DAD (liquid chromatography-diode array detector) data is a time-consuming and subjective task. This paper describes an algorithm that efficiently extracts such differences.

Journal Article↗

The importance of the cell sample in cervical cytology: a controlled trial of a new sampling device.

The provision of a truly-representative cellular sample is the major prerequisite for reliable cervical cytology. We performed a trial with a cervical-sampling implement of innovative design, the Cervex Sampler. By means of the parameters of patient and doctor acceptability, the quality of the smear, the presence of endocervical cells, and the rate of squamous-cell atypia, the Cervex Sampler was compared with a modified Ayre spatula. One hundred samplers were distributed to each of 10 doctors. The parameters were assessed before, during and after the trial period. The consensus was that the Cervex Sampler was easier to use and did not cause patients any problems. Assessment of the smears that were made with the Cervex Sampler showed a significant improvement in the quantity and evenness of the distribution of the cellular sample. During the trial, statistically-significant increases occurred in the percentage of smears that contained endocervical cells (P = 0.0001) and atypical squamous cells (P = 0.028). At the end of the trial, when the doctors again used the modified Ayre spatula, these rates reverted to the same levels as before.

Equipment Design↗

[A personal sampling and an area sampling--exposure concentration and environmental concentration].

Two methods for the evaluation of air contaminant in a work environment are personal sampling to measure the exposure concentration for the evaluation of the exposure level to workers and area sampling that measures the environmental concentration for the evaluation of the clean level in the work environment. The aim of these samplings is different but they are used to measure the concentration in the same work environment. It is important to understand the difference between the exposure concentration and the environmental one in the same work environment. In this report, the relationship between the exposure concentration and the environmental one is investigated by using previous reported data. The difference between the exposure concentration and the environmental one is very large for all data, but the exposure concentrations agree well with the environmental ones when the both concentrations were measured by the same apparatus in some work environments.

Air Pollutants, Occupational↗

[Detection of Chlamydia trachomatis infection among young people. The effect of home-sampling and mailing the samples].

Genital Chlamydia trachomatis infection is common and treatable, but often asymptomatic. New diagnostic strategies targeting healthy individuals are therefore needed. The 17 high schools in Aarhus County, Denmark, comprising 8909 students, were cluster-randomized into an intervention group which was offered examination by mailing a urine sample (males and females) and a vaginal flush sample (females) directly to the laboratory, and a control group who were offered examination by a physician. Ninety-three percent (867/928) of the sexually experienced female responders underwent examination in the intervention group, compared with 8% (63/833) in the control group (p < 0.001). The corresponding figures for males were 97%, (430/442) and 2% (4/246), respectively (p < 0.001). Also statistically significantly more infected females and males were found in the intervention group (43 females and 11 males in the intervention group vs. five females and one male in the control group). Home sampling improves the diagnosis of C trachomatis infection among apparently healthy young individuals.

Adolescent↗

Cryo-techniques applied to stratum corneum with description of a new sample holder for cryo-scanning electron microscopy of freeze-fractured samples.

Stratum corneum structure greatly differs from that of the living epidermis and specific sample cryo-preparation techniques have to be used. Practical aspects of these cryo-techniques applied to stratum corneum are discussed. Emphasis is placed on scanning electron microscopy of cryo-fixed samples. A new sample holder designed for cryo-scanning electron microscopy of freeze-fractured stratum corneum is described.

Cryoelectron Microscopy↗

An automated sequential sampling system for particulate acid aerosols: description, characterization, and field sampling results.

An automated sequential sampling system for the measurement of particulate acid aerosols was developed in order to allow the routine collection of daily samples with only once-per-week site visits. The system's design, operation, and associated quality assurance (QA), quality control (QC), and data validation procedures are described. Results from a multi-year field application of this system in the Buffalo, Albany, and New York City metropolitan areas are reported, as well as from external audits and interlab analytical intercomparisons. It is found that the system successfully collected 94% of all possible samples in these three cities between May 1988 and December 1989. Weekly QA field blanks and positive control filters indicate that these data were collected with negligible acid contamination or neutralization. Peak aerosol acidity levels at these sites were found to be highest during the summer months, with peak 24-hr average levels in the 300-400 nmol/m3 range. It is concluded that this system represents a more convenient means of collecting extended daily records of valid particulate acid aerosol concentrations than has been possible in the past.

Acids↗

Effect of sample aging on patient samples kept at ambient temperature before analysis with the Abbott Cell-Dyn 4000 hematology analyzer.

The effect of sample aging was studied on 80 blood samples collected from in-house patients within 2 hours before aspiration into the Cell-Dyn 4000 hematology analyzer. The first aspiration defined the zero-time value, and the samples were stored at ambient room temperature (23 degrees C) and reanalyzed at 12, 24, 48, 72, and 145 hours. Statistical analyses were made against the matched zero-time result for each patient. We report that the total white blood cell count is reliable for up to 24 hours, and that the 5-part differential count is reliable for up to 12 hours, being limited by the fragile eosinophils. This report shows that within 24 hours the neutrophil count, combined with the white cell count, is a more robust indicator of deviation of the main leukocyte subpopulation than the 5-part differential count. The platelet count was reliable for up to 12 hours. The erythrocyte mean cell volume (MCV) increased continuously during the observation period. In contrast, mean cell hemoglobin (MCH) showed a very small decrease after 72 hours. It is therefore proposed that MCH, and not MCV, should be used for diagnosis of the type of anemia.

Blood Cell Count↗

Performance of proficiency survey samples in two immunoradiometric assays of human growth hormone and comparison with patients' samples.

The immunoradiometric assay (IRMA) used in our laboratory for the measurement of growth hormone (hGH; somatotropin) performed badly in the national proficiency survey program, the U.K. External Quality Assessment Scheme (EQAS). We compared our assay with another IRMA, which gave similar results for patients' samples and performed adequately in EQAS. The samples from EQAS are collected from patients with polycythemia and fall into two categories: those containing endogenous hGH and those supplemented with pituitary-derived hGH. Analysis of the two groups separately showed that the differences between the two IRMAS were in the measurement of the endogenous hormone. The reason for this appears to be a matrix effect related to the fact that the EQAS serum samples are collected from polycythemic patients.

Growth Hormone↗

[Comparison of single plasma sample methods and prediction of dual plasma sample method in measurement of 99mTc-Diethylene Triamine Pentaacetic Acid plasma clearance].

OBJECTIVE: To find an applicable condition of the single-plasma-sample method (SPSM) to measure the glomerular filtration(GFR) with (99m)Tcj Diethylene Triamine Pentaacetic Acid ((99m)Tc-DTPA), and predict the value of (99m)Tc-DTPA plasma clearance by dual plasma sample method (DPSM ) from that by SPSM. METHODS: Three hundred and thirty five patients with chronic kidney disease (CKD) were selected (192 males and 143 females). The average age was 51.91+/-14.76 years. The GFR was determined simultaneously by 2 methods: (1) SPSM (sGFR); (2) DPSM (tGFR), using DPSM as reference standard, sGFR calculated from the different SPSM was compared with tGFR. An equation was developed to predict tGFR from sGFR. GFR estimated by abbreviated Modification of Diet in Renal Disease (MDRD) equation (aGFR) was evaluated as the criterion in selection of DPSM and SPSM. The condition that DPSM could be substituted by SPSM in GFR measurement was given. RESULTS: When tGFR >or= 30 mL/(minx1.73 m(2)), all of the sGFR were significantly correlated with tGFR. Among them, Watson modified Christensen and Groth's equation at sample time=240 min tended to be the most accurate (r=0.977, RMSE=10.91), and tGFR could be predicted from sGFR using the equation: Predicted tGFR [mL/(minx1.73 m(2))]=7.755 4+0.789 3xsGFR+0.002 4 xsGFR2 (n=297, r2=0.959 1, P<0.001). When aGFR was less than 50 mL/(minx1.73 m(2)), the diagnostic sensitivity of tGFR<30 mL/(minx1.73 m(2)) was 94.7%, and recommended as the criterion in selection of DPSM and SPSM. CONCLUSION: When aGFR >or=50 mL/(minx1.73 m(2)), DPSM can be substituted by SPSM in GFR measurement.

Algorithms↗