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PubMed1985

The determination of specific radioactivity of proteins eluted intact from polyacrylamide gels, utilizing a fluorescamine assay.

The methodology described permits the measurement of the specific radioactivity of diverse proteins resolvable by separatory techniques using cylindrical polyacrylamide gels. Following separation, the proteins are electroeluted; eluted protein is quantitated in the microgram range using a fluorescamine assay, while the major portion of the recovered sample is used for radioactivity measurement. These procedures have been adapted for use in tracer studies of protein metabolism. Their utility in kinetic investigations is demonstrated with data on the time course of changing specific radioactivities of human plasma albumin and apolipoprotein B labeled in vivo with a [3H]leucine tracer.

Apolipoproteins B↗
PubMed1991

A microassay for protein glycation based on the periodate method.

The periodate assay for glycated protein has been adapted for use with a microplate reader. Up to 94 samples can be read in 40 s, and sensitivity has been improved so that only 2-40 nmol of protein-bound sugar are needed per well. Yields have been increased to over 90%, allowing in vitro glycation of human serum albumin to be assayed on 0.1-mg aliquots.

Glycoproteins↗
PubMed1991

Application of two RNA extraction methods prior to amplification of hepatitis E virus nucleic acid by the polymerase chain reaction.

Amplification of the enterically-transmitted non-A, non-B hepatitis virus (HEV) RNA using conventional reverse transcriptase reactions followed by the polymerase chain reaction (PCR) of the cDNA has not been successful. However, after application of two different RNA capture/extraction methods we were able to amplify HEV nucleic acid from clinical samples and specimens from experimentally infected animals. The first procedure, adapted from an immune electron microscopy (IEM) technique, incorporated an immunocapture step with concentration of the virus-antibody complexes by pelleting in a Beckman airfuge. In the second method, glass powder (or size-fractionated silicon dioxide) was used to capture the RNA from its surrounding milieu by adsorption of the nucleic acid to the silicate particles. Since conventional immunoassays for HEV antigen or antibody are not currently available, the use of these RNA extraction methods, coupled with PCR techniques, will be valuable in screening clinical specimens and in further defining the course of disease using animal infectivity studies.

Adsorption↗
PubMed1988

Phylogeny of Onchocerca volvulus and related species deduced from rRNA sequence comparisons.

A rapid, direct method for determining the partial nucleotide sequence of large subunit ribosomal RNA was adapted and applied to a group of helminth parasites. Small samples of total, unfractionated cellular RNA isolated from each organism were analysed and the nucleotide sequences of equivalent portions of the large subunit ribosomal RNA compared. The data obtained were used to construct a phylogenetic tree showing the evolutionary relationships within this group of organisms.

Animals↗
PubMed1992

Quantitative analysis of retinoids in biological fluids by high-performance liquid chromatography using column switching. III. Determination of the arotinoid sumarotene and its Z-isomer in human and animal plasma.

A fully automated and sensitive high-performance liquid chromatographic method, using on-line solid-phase extraction, automated column switching and ultraviolet detection, was developed for the third-generation retinoid (arotinoid) sumarotene (methyl p-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthyl)propenyl]phe nyl sulphone; Ro 14-9706) and its Z-isomer. Nearly quantitative recoveries for human, rat and dog plasma were obtained by addition of acetonitrile (final content ca. 17%) to the plasma sample prior to injection. No isomerization was observed when the samples were stored in the autosampler for more than 20 h. The injection volume was 0.5 ml, resulting in quantification limits of 1 ng/ml for sumarotene and 2 ng/ml for the Z-isomer. More than 40 injections could be made on to one precolumn, allowing routine overnight injections. Using a 1-ml injection volume, the limit of quantification for sumarotene could be improved to 0.5 ng/ml. The method was applied to toxicokinetic studies in rats and dogs, and was used to monitor human plasma samples after repeated topical application. The method could also be adapted to etarotene (Ro 15-1570), which was used as an internal standard, and which is at present in clinical development.

Animals↗
PubMed1985

Screening of medicinal plants used by Huastec Mayans of northeastern Mexico.

As part of a research effort to assess the adaptive value of Huastec medicine, a preliminary screening of a sample of the Huastec pharmacopoeia has been carried out. Results from the screening of 56 species are reported here together with information about Huastec use and knowledge of medicinal plants.

Culture↗
PubMed2006

Increasing the temporal g(r)ain: double-pulse resolution is affected by the size of the attention focus.

Spatial cueing of transient attention has recently been shown to reduce temporal sensitivity. We investigated how the size of the sustained attentional focus influences double-pulse resolution (DPR) thresholds mapped across the visual field in a sample of 95 healthy subjects using a 9-fold interleaved adaptive algorithm (YAAP). Peripheral DPR thresholds increased for measurements between 2.5 degrees and 20 degrees eccentricity. Additionally, central DPR thresholds increased at a similar rate when measured with increasingly larger stimulus displays for peripheral measurements. This latter effect suggests that temporal resolution decreases with a larger sustained attention focus and cannot be explained by retinal characteristics only.

Adolescent↗
PubMed2001

Planar Procrustes analysis of tooth shape.

Accurate quantification of variation in tooth shape is important in studies of dental development, which typically have involved measuring distances between subjectively identified landmarks, key points of correspondence on teeth. An established statistical framework now exists for the analysis of shape when objects are represented as configurations of landmark coordinates; allowing work with the full geometry of objects, which is otherwise lost. This approach was introduced here to the study of tooth morphology, demonstrating how after optimally matching shapes to account for the unwanted effects of location, scale and rotation, most standard descriptive and inferential statistical techniques can be adapted and applied successfully. The techniques are illustrated using a sample of buccal-surface images of central incisors from patients with hypodontia; a significant difference is found in mean buccal-surface shape (Hotelling's two-sample T(2)-test; P=0.004) when compared to a corresponding control group. Successful implementation of these methods depends on the accuracy and reliability with which the landmarks are collected; issues and problems to be addressed are discussed.

Algorithms↗
PubMed2001

A molecular biomarker system for assessing the health of gastropods (Ilyanassa obsoleta) exposed to natural and anthropogenic stressors.

We developed a Molecular Biomarker System (MBS) to assess the physiological status of mud snails (Ilyanassa obsoleta) challenged by exposure to high temperature, cadmium, atrazine, endosulfan and the water-accommodating fraction of bunker fuel #2. The MBS is used to assay specific cellular parameters of the gastropod cell that are indicative of a non-stressed or stressed condition. The MBS distinguished among responses to each stressor and to non-stressed control conditions. For example, the biomarkers metallothionein and cytochrome P450 2E1 homologue distinguished between metal and non-metal stresses. MBS data from this study corroborate toxicological studies of organismal responses to endosulfan, atrazine, fuel and cadmium stresses. The MBS technology aids in the accurate diagnosis of the snail's health condition because the physiological significance of the changes of each biomarker is well known. This technology is particularly relevant for environmental monitoring because gastropods are used as key indicator species in many estuarine, marine, freshwater and terrestrial ecosystems. Finally, the Molecular Biomarker System technology is relatively inexpensive, easy to implement, precise and can be quickly adapted to an automated, high-throughput system for large sample analysis.

Journal Article↗
PubMed2003

Preliminary evidence of striatal D2 receptor density as a possible biological marker of prognosis in naive schizophrenic patients.

UNLABELLED: With the aim of investigating a possible biological marker of prognosis in schizophrenia, the relationship between striatal dopaminergic D2 receptor (D2R) density and clinical prognostic factors was studied in an initial sample of nine neuroleptic-naive schizophrenic patients. Previous psychosocial adaptation was evaluated by means of the Premorbid Adjustment Scale (PAS). Based on the four DSM-IV criteria in schizophreniform disorder for good prognosis, patients were divided in two groups: good prognosis if > or =2 criteria were met (n=5) and poor prognosis if <2 criteria were met (n=4). D2R density was assessed by means of 123I-IBZM single photon emission computed tomography (SPECT) and striatum/occipital uptake ratios (S/O). S/O ratios previously obtained from a control group of nine age- and sex-matched healthy volunteers were used for comparison. RESULTS: Patients with poor prognosis showed a higher S/O ratio (mean=1.94, range=1.93-1.98) than patients with good prognosis (mean=1.64, range=1.52-1.79) and the control group (mean=1.69, range=1.51-1.85) [analysis of variance (ANOVA) F=10.628, df=2, P=.001, post hoc Scheffé P<.005]. PAS scores were significantly different between patients with good and poor prognosis (40+/-9.39 vs. 84.25+/-26, Mann-Whitney U-test P=.014). A direct correlation of S/O ratios with PAS scores was found (Spearman r=.72, P=.028). CONCLUSIONS: Striatal D2R density in naive schizophrenic patients may be related to DSM-IV prognostic factors and premorbid adjustment criteria (PAS). If these preliminary results are confirmed, striatal D2R density might predict premorbid and clinical features associated with poor prognosis in neuroleptic-naive patients.

Adolescent↗
PubMed2000

A novel rapid colorimetric assay of carcinoembryonic antigen levels in the abdominal cavity to detect peritoneal micrometastasis during gastric cancer surgery.

We showed that the carcinoembryonic antigen (CEA) level in a peritoneal washing is an indicator of the postoperative survival of gastric cancer patients. On the premise that the polyvinylidine difluoride membrane adsorbs a fixed quantity of protein, this study was designed to produce a rapid, colorimetric, semi-quantitative assay of peritoneal CEA levels by using anti-CEA antibodies. At the time of laparotomy, peritoneal washings were collected from 60 gastric cancer patients, and CEA levels were determined by our assay and by an enzyme immunoassay (EIA) method. The accuracy of our method corresponded with the results of the EIA method. All the cases with high levels of CEA in the peritoneal washings showed positive color changes. Our new assay had no relation to protein concentrations of the samples. The assay makes use of diluted peritoneal washings without adaptation by protein concentration. The measurement can be completed in the operating room within 30 min. As a result, this assay can detect peritoneal microdissemination easily during surgery, and it can be used as an indication of intraoperative chemotherapy against peritoneal micrometastasis.

Abdomen↗
PubMed2001

Minimum detectable activity in in situ gamma-ray spectrometry.

The algorithm used to calculate a minimum detectable activity (A(D)) of an environmental volume sample measured by gamma-ray spectrometry was modified and adapted for in situ measurements performed at the standard 1 m height above ground. AD values of target radionuclides were determined from the in situ spectra collected at two disparate sites. A linear relationship between the two sets of A(D)s was found and the ratio between these two sets is equal to the square root of the ratio of the two respective absorbed dose rates measured at the sites at 1 m height. Absorbed dose rates were calculated using the concentration of potassium, thorium and uranium in the soils at the sites and found to agree well with the measured values. A(D) values can be predicted easily in in situ gamma spectrometry applying a simple experimental procedure that is based on the linear relationship.

Journal Article↗
PubMed2004

Month of birth, socioeconomic background and development in Swedish men.

Season of birth has been shown to correlate with many aspects of somatic and mental disorders, development and social adaptation (so-called 'birth-date effects'). In a sample of young Swedish men, corresponding roughly to a one-year birth cohort, the results of intelligence tests, psychologists' ratings of psychological function, school achievement, body height, weight and self-reported health during childhood, were found to be correlated with month of birth, and--more strongly--father's socioeconomic status. The results were more favourable for men who were born during March-May (the period of highest birth rate), and whose fathers were of higher socioeconomic status, than for those born in November and December (the period of lowest birth rate), and whose fathers were in the lower socioeconomic group. It seems reasonable to conclude, from this study and previously reported findings, that these so-called 'birth-date effects' are determined by varying and often interacting biological and psychosocial factors. Among these factors, the light-induced entrainment of circadian and annual rhythms in the fetus and/or infant seems to be of pivotal importance. The organization of children into one-year age classes therefore produces an unfair lack of equality of possibilities.

Anthropometry↗
PubMedDate not supplied

Activity correlates of cytochrome oxidase-defined compartments in granular and supragranular layers of primary visual cortex of the macaque monkey.

To determine if changes in metabolic capacity revealed by cytochrome oxidase (CO) histochemistry are related to sustained changes in energy-utilizing neuronal activity, we assayed CO levels and recorded multiunit firing rates along nearly tangential penetrations of V1 in seven adult macaque monkeys before and after single, monocular injections of TTX. Within as little as 14 h, TTX blockade began to reduce CO staining in zones of layer 4C that received dominant input from the injected eye. Since simple monocular occlusion has only minor effects on cortical CO levels (Trusk et al., 1990), the changes in activity that were specifically associated with CO depletion were isolated by comparing spike rates during monocular TTX blockade and during monocular occlusion. Five second samples of multiunit spike rate were obtained after 2-min adaptation to each of four adapting fields: black, gray, white, and textured. Results were similar for these four conditions. In layer 4C, ocular dominance zones with input from the TTX eye had ongoing spike rates that were 48% of the rates in zones with input from a normal but occluded eye. In six animals, it was possible to record activity at a single site before, during, and after the onset of TTX blockade. Background activity at these interpuff sites decreased as much as 3-fold in less than 1 h but stabilized within 3-4 h to an average of 53% of pre-TTX rates. These data support the interpretation that energy utilization linked to sustained spike rates partially regulates CO levels under normal conditions, at least in layer 4. Furthermore, changes in neuronal activity induced by retinal TTX preceded the detectable reduction in CO activity in V1 suggesting that the adjustment of CO levels was in response to the altered activity.

Action Potentials↗
PubMed2002

Effortful control: factor structure and relation to externalizing and internalizing behaviors.

Effortful control, a temperamentally based ability to inhibit a dominant response and activate a subdominant response, was assessed on 3 occasions using a comprehensive, age-appropriate behavioral battery in this 4-year longitudinal study of children (N = 103) from toddlerhood to early school age. The focus was twofold: to explore the structure of effortful control in a normally developing sample and to examine the relations between effortful control and adaptive functioning. Exploratory factor analyses supported the contention that effortful control is a complex, multidimensional construct with longitudinally stable factors. Effortful control was also significantly associated with mother-reported total behavior problems in a nonlinear fashion, with lower and higher levels of effortful control contributing to higher total problem scores. These findings have implications for the assessment of temperament in children and, most importantly, for the study of nonlinear contributions of temperament to early childhood behaviors.

Adaptation, Psychological↗
PubMed1996

Multicolour spectral karyotyping of mouse chromosomes.

Murine models of human carcinogenesis are exceedingly valuable tools to understand genetic mechanisms of neoplastic growth. The identification of recurrent chromosomal rearrangements by cytogenetic techniques serves as an initial screening test for tumour specific aberrations. In murine models of human carcinogenesis, however, karyotype analysis is technically demanding because mouse chromosomes are acrocentric and of similar size. Fluorescence in situ hybridization (FISH) with mouse chromosome specific painting probes can complement conventional banding analysis. Although sensitive and specific, FISH analyses are restricted to the visualization of only a few mouse chromosomes at a time. Here we apply a novel imaging technique that we developed recently for the visualization of human chromosomes to the simultaneous discernment of all mouse chromosomes. The approach is based on spectral imaging to measure chromosome-specific spectra after FISH with differentially labelled mouse chromosome painting probes. Utilizing a combination of Fourier spectroscopy, CCD-imaging and conventional optical microscopy, spectral imaging allows simultaneous measurement of the fluorescence emission spectrum at all sample points. A spectrum-based classification algorithm has been adapted to karyotype mouse chromosomes. We have applied spectral karyotyping (SKY) to chemically induced plasmocytomas, mammary gland tumours from transgenic mice overexpressing the c-myc oncogene and thymomas from mice deficient for the ataxia telangiectasia (Atm) gene. Results from these analyses demonstrate the potential of SKY to identify complex chromosomal aberrations in mouse models of human carcinogenesis.

Animals↗
PubMed2004

Overweight and obesity in children with Attention-Deficit/Hyperactivity Disorder.

OBJECTIVE: Epidemiological studies suggest that adiposity in children may be associated with a reduced level of physical activity. Children with Attention-Deficit/Hyperactivity Disorder (ADHD) are physically hyperactive as of early childhood and have been shown to exhibit higher levels of motor activity than normal. The aim of our study was to assess if the prevalence of overweight and obesity is lower in a population of boys with ADHD in comparison with the German healthy male reference population of the same age. DESIGN: Patients were investigated from 1999 until 2001 upon referral to the inpatient and outpatient unit of the Department of Child and Adolescent Psychiatry of the University of Aachen. SUBJECTS: A total of 97 male patients (mean age 10+/-2 y) with a diagnosis of ADHD according the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV), who were free of potentially orexigenic medication and who had no further comorbid diagnosis apart from conduct disorder. MEASUREMENTS: BMI standard deviation scores (BMI-SDS) were calculated and compared to age-adapted reference value of the German population. RESULTS: Patients' mean BMI-SDS was significantly higher than the age-adapted reference values of the German population (P=0.038). Our sample included significantly more subjects than expected with a BMI > or =90th percentile (19.6%, P<0.001) and > or =97th percentile (7.2%, P=0.007). CONCLUSION: Surprisingly, being 'hyperactive' in the sense of the DSM-IV diagnosis of ADHD does not prevent the development or persistence of overweight and obesity in children. The examination of these children might be a helpful approach in the investigation of the relationship between obesity and its contributing psychological and behavioural factors.

Adolescent↗
PubMed2003

Multi-analyte optimisation of uncertainty in infant food analysis.

The Optimised Uncertainty (OU) methodology has been developed to optimise multi-analyte situations. It has then been applied to a retail survey of infant food for trace elements, classifying the food as compliant or non-compliant with the regulatory thresholds or specification limits that are appropriate for each element. The large-scale survey of infant foods was successfully adapted to allow the estimation of uncertainties, from both primary sampling and chemical analysis, for elemental concentrations in infant formula (milk) and wet meals. The analytes included in this investigation comprised both contaminants (Pb and Cd) and elements essential for child development (Zn and Cu). Optimisation of the measurement process for a 'single analyte' demonstrated the potential financial benefits of optimising future surveys for a false compliance scenario. Uncertainty estimates for the measurement of elemental concentrations in infant formula were dominated by uncertainty from the analytical method. Large potential savings (up to pounds 575,000 per batch) are predicted for both Pb and Zn by increasing the expenditure on chemical analysis to the optimal level. In comparison the uncertainty estimates for elemental concentration in wet meals showed a dominance of sampling as a source of uncertainty for Cd and Cu due to the increased heterogeneity. The feasibility of 'multi-analyte' optimisation is demonstrated for the case study of infant milk. Single analyte optimisation of the four analytes for a false compliance scenario indicated a decrease in expectations of financial loss of between 99% and 8%. An overall decrease in the total expectation of financial loss of 99% is indicated following multi-analyte optimisation.

Child, Preschool↗