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At least 1,423 records · Page 79Linked to original sources
PubMed2004

Receptor imaging in oncology by means of nuclear medicine: current status.

To date, our understanding of the role of receptors and their cognate ligands in cancer is being successfully translated into the design and development of an arsenal of new, less toxic, and more specific anticancer drugs. Because most of these novel drugs are cytostatic, objective response as measured by morphologic imaging modalities (eg, computed tomography or magnetic resonance imaging) cannot be used as a surrogate marker for drug development or for clinical decision making. Positron emission tomography (PET) can be used to image and quantify the in vivo distribution of positron-emitting radioisotopes such as oxygen-15, carbon-11, and fluorine-18 that can be substituted or added into biologically relevant and specific receptor radioligands. Similarly, single-photon emission computed tomography (SPECT) can be used to image and quantify the in vivo distribution of receptor targeting compounds labeled with indium-111, technetium-99m, and iodine-123. By virtue of their whole-body imaging capacity and the absence of errors of sampling and tissue manipulation as well as preparation, both techniques have the potential to address locoregional receptor status noninvasively and repetitively. This article reviews available data on the in vivo evaluation of receptor systems by means of PET or SPECT for identifying and monitoring patients with sufficient receptor overexpression for tailored therapeutic interventions, and also for depicting tumor tissue and determining the currently largely unknown heterogeneity in receptor expression among different tumor lesions within and between patients.

Humans↗
PubMed1978

Nongranulomatous interstitial pneumonitis in sarcoidosis. Relationship to development of epithelioid granulomas.

Nongranulomatous, nonspecific interstitial pneumonitis was a predominating or prominent histopathologic finding in 62 percent of 128 granuloma-containing specimens from open lung biopsies obtained from patients with sarcoidosis. Data from this study, combined with observations by others on the evolution of experimentally induced granulomas, indicate that interstitial pneumonitis represents a very early lesion, possibly the initial lesion, in pulmonary sarcoidosis. Because of the relatively large error of sampling inherent in the currently increasing practice of obtaining small specimens for lung biopsy via the flexible fiberoptic bronchoscope, we anticipate that interstitial pneumonitis will be seen as the only histopathologic finding in these specimens with increasing frequency. It is therefore important to recognize that interstitial pneumonitis is a characteristic, although nondiagnostic, morphologic feature of pulmonary sarcoidosis.

Adolescent↗
PubMed2005

Quantifying test-retest reliability using the intraclass correlation coefficient and the SEM.

Reliability, the consistency of a test or measurement, is frequently quantified in the movement sciences literature. A common metric is the intraclass correlation coefficient (ICC). In addition, the SEM, which can be calculated from the ICC, is also frequently reported in reliability studies. However, there are several versions of the ICC, and confusion exists in the movement sciences regarding which ICC to use. Further, the utility of the SEM is not fully appreciated. In this review, the basics of classic reliability theory are addressed in the context of choosing and interpreting an ICC. The primary distinction between ICC equations is argued to be one concerning the inclusion (equations 2,1 and 2,k) or exclusion (equations 3,1 and 3,k) of systematic error in the denominator of the ICC equation. Inferential tests of mean differences, which are performed in the process of deriving the necessary variance components for the calculation of ICC values, are useful to determine if systematic error is present. If so, the measurement schedule should be modified (removing trials where learning and/or fatigue effects are present) to remove systematic error, and ICC equations that only consider random error may be safely used. The use of ICC values is discussed in the context of estimating the effects of measurement error on sample size, statistical power, and correlation attenuation. Finally, calculation and application of the SEM are discussed. It is shown how the SEM and its variants can be used to construct confidence intervals for individual scores and to determine the minimal difference needed to be exhibited for one to be confident that a true change in performance of an individual has occurred.

Humans↗
PubMed2001

[Health risk behaviors, health status self-assessment and stress perception among industrial workers].

OBJECTIVE: To identify the prevalence and association among health risk behaviors, stress perception, and health status self-assessment among industrial workers. METHODS: A cross-sectional study was performed using a questionnaire previously tested in a pilot study in the State of Santa Catarina, Brazil. Data on smoking, alcohol consumption, fruit and vegetables intake, physical activity, stress perception, and self-assessment of health status were available for 4,225 workers (67.5% males and 32.5% females). Subjects were selected using a 3-stage cluster sampling (5% error margin). Statistical analysis was performed using Chi-square, and logistic regression analysis (p<0.05). RESULTS: The mean age was 29.7 years old (SD=8.6). The prevalence of smokers was 20.6%, higher among males (23.1%) than females (15.6%). The proportion of heavy drinkers was high (57.2% among males and 18.8% among females). Almost half of the subjects (46.2%) reported no leisure-time physical activity (67% females and 34.8% males). Approximately 14% of subjects reported high levels of stress and difficulty to cope with daily tasks. About 15% of the workers perceived their health status as regular or poor. Gender, age, marital status, number of children, educational level and economic status were significantly associated with the prevalence of health risk behaviors. CONCLUSIONS: Despite the limitations of cross-sectional studies, based on self-report assessments, the study results suggest a high prevalence of alcohol consumption and physical inactivity during leisure time. The observed association between gender and health risk behavior suggests that both sexes engage in risk behaviors: for men these behaviors are direct or active (smoking, alcohol consumption) and for women, they are more indirect or passive (physical inactivity, stress).

Adult↗
PubMed2003

The association of genetic markers and malaria infection in the Brazilian Western Amazonian region.

Almost all individuals (182) belonging to an Amazonian riverine population (Portuchuelo, RO, Brazil) were investigated for ascertaining data on epidemiological aspects of malaria. Thirteen genetic blood polymorphisms were investigated (ABO, MNSs, Rh, Kell, and Duffy systems, haptoglobins, hemoglobins, and the enzymes glucose-6-phosphate dehydrogenase, glyoxalase, phosphoglucomutase, carbonic anhydrase, red cell acid phosphatase, and esterase D). The results indicated that the Duffy system is associated with susceptibility to malaria, as observed in other endemic areas. Moreover, suggestions also arose indicating that the EsD and Rh loci may be significantly associated with resistance to malaria. If statistical type II errors and sample stratification could be ruled out, hypotheses on the existence of a causal mechanism or an unknown closely linked locus involved in susceptibility to malaria infection may explain the present findings.

Adolescent↗
PubMed2004

Validation of housekeeping genes for normalizing RNA expression in real-time PCR.

Analysis of RNA expression using techniques like real-time PCR has traditionally used reference or housekeeping genes to control for error between samples. This practice is being questioned as it becomes increasingly clear that some housekeeping genes may vary considerably in certain biological samples. We used real-time reverse transcription PCR (RT-PCR) to assess the levels of 13 housekeeping genes expressed in peripheral blood mononuclear cell culture and whole blood from healthy individuals and those with tuberculosis. Housekeeping genes were selected from conventionally used ones and from genes reported to be invariant in human T cell culture. None of the commonly used housekeeping genes [e.g., glyceraldehyde-phosphate-dehydrogenase (GAPDH)] were found to be suitable as internal references, as they were highly variable (>30-fold maximal variability). Furthermore, genes previously found to be invariant in human T cell culture also showed large variation in RNA expression (>34-fold maximal variability). Genes that were invariant in blood were highly variable in peripheral blood mononuclear cell culture. Our data show that RNA specifying human acidic ribosomal protein was the most suitable housekeeping gene for normalizing mRNA levels in human pulmonary tuberculosis. Validations of housekeeping genes are highly specific for a particular experimental model and are a crucial component in assessing any new model.

Cells, Cultured↗
PubMed2004

caGEDA: a web application for the integrated analysis of global gene expression patterns in cancer.

The explosion of microarray data from pilot studies, basic research and large-scale clinical trials requires the development of integrative computational tools that can not only analyse gene expression patterns but that can also evaluate the methods of analysis adopted and then provide a boost to post-analysis translational interpretation of those patterns. We have developed a web application called caGEDA (cancer gene expression data analyzer) that can: (1) upload gene expression profiles from cDNA or oligonucleotide microarrays; (2) conduct a diverse range of serial linear normalisations; (3) identify differentially expressed genes using a variety of tests - either threshold or permutation tests; (4) produce tables of literature references to papers reporting that specific genes (identified by accession numbers) are up- or down-regulated in specific cancers; (5) estimate the error of sample class prediction using the significant gene set for features; (6) perform low-bias and accurate validated learning using three computational validation techniques (leave-one out validation, k-fold validation, random re-sampling validation); and (7) validate a classifier with a randomly selected or user-defined validation set. Significant genes are reported in a table of links to entries in the following databases: Locus Link, Genome View, UCSC, Ensembl, UniGene, dbSNP, AmiGO and OMIM. caGEDA is seamlessly integrated via embedded forms with UCSD's (University of California at San Diego) 2HAPI server (for medical subject heading (MeSH) term exploration) and EZ-Retrieve (to identify common transcription factors located upstream of sets of genes that exhibit similar modes of differential expression). caGEDA offers a variety of previously described and novel tests for differentially expressed genes, most notably the permutation percentile separability test, which is most appropriate for identifying genes that are significantly differentially expressed in a subset of patients. caGEDA, which is open source and free to academic users, will soon be greatly enhanced by operating with the components of the National Cancer Institute's new cancer bioinformatics grid (caBIG).

Biomarkers, Tumor↗
PubMed1991

Cerebellar control of saccadic eye movements: its neural mechanisms and pathways.

Microstimulation studies on monkeys have shown that the cerebellar cortex which is related to saccadic function is located in lobules VIc and VII of the vermis. This vermal area is designated as the oculomotor vermis and characterized by low thresholds (less than 10 microA) and by saccade-related neuronal activity. The saccade evoked by the vermal stimulation has been shown to be the result of activation of Purkinje-cell axons. On the other hand, an anterograde WGA-HRP transport study has indicated that the Purkinje-cell axons of the oculomotor vermis terminate almost exclusively in a fatigial region which is designated as the fastigial oculomotor region (FOR). Microstimulation of the oculomotor vermis and the ventromedial aspect of the FOR results in saccades which differ in their horizontal directions, with vermal stimulation resulting in ipsilateral and fastigial stimulation resulting in contralateral saccades. Since the ipsilateral saccades evoked from the caudal part of the FN were suppressed by bicuculline, they were the results of stimulation of the Purkinje axons. It has been also shown that stimulation of the oculomotor vermis causes inhibition of FOR neurons. Furthermore, fastigial neurons bursting with saccades can be recorded only within the anatomical confines of the FOR. These data are consistent with the concept that signals from the vermis are transmitted to the saccadic nuclei of the brainstem via the FOR. Neurons in the FOR have been shown to project to various saccade-related nuclei, including the riMLF and PPRF. Some neurons in the FOR have divergent axon collaterals which terminate in both the vertical and horizontal preoculomotor nuclei. When the initial eye position is changed by stimulating the FN prior to visually-guided saccades, monkeys cannot compensate for the stimulation-induced movement. When the stimulation is delived 75-130 ms after the target presentation, saccades are triggered prematurely. The visuomotor processing for saccades seems to be completed during this period, which is approximately half the latency of normal saccades. When saccades were triggered prematurely at an early stage of information processing, the eyes moved first in the direction of evoked saccade and then changed the direction toward the location of the target without any intervening period. The retinal error information sampled before the stimulation was not disturbed by the cerebellar stimulation. These observations suggest that cerebellar output impulses are projected downstream to saccade-programming circuits where visual information has already been converted into motor-command signals. The cerebellum is a domain for parallel processing of visuomotor information.

Animals↗
PubMed1977

Negative smears in women developing invasive cervical cancer.

Fifty-six cervical smears originally classified as Pap. I, from women in whom cervical cancer of stage I to IV was detected within 4 to 5 years after the cytological check, were re-examined in order to estimate the screening error and sampling failure. At the review, 35 smears were classified as Pap. II to V. The incidence of changed classification of the smears obtained from population screening was 70% and that of the smears taken at private specialists or at hospitals was about 50%. The influence of sampling failure on the evaluation of the smears classified as Pap. II should be considered. On 14 slides, correctly interpreted as negative, there were no columnar cells present, a fact that may indicate inefficient sampling of cells from the squamo-columnar junction.

Adenocarcinoma↗
PubMed1995

Circadian differences in hemisphere-linked spelling proficiencies.

Male and female adolescents (N = 113) were assigned randomly to spelling instruction in either morning or afternoon groups for a school year. A spelling list (100 words) was administered at the beginning of the school year to obtain a sample of error responses and estimate proficiency. Although equally proficient, subjects tested in the afternoon showed more phonetically inappropriate errors, while those tested in the morning showed more phonetically appropriate errors. This error pattern is viewed as support for a more engaged left hemisphere in the morning. There were no differences on two types of visual errors. Subjects then received instruction in spelling for nine months in either morning or afternoon settings. Time-of-day effects were not evident on the word list and there were too few errors to conduct a posttest error analysis. However, standardized test results for a subgroup revealed that subjects receiving morning instruction made greater gains on phonetically regular words compared to phonetically irregular words--an effect consistent with a circadian-linked higher level of left hemisphere engagement early in the day. The findings are of a pilot nature, but implications for education and further research are discussed.

Achievement↗
PubMed1996

Advantages and disadvantages of current diagnostic tests for the detection of Helicobacter pylori.

Current tests used to detect Helicobacter pylori are either invasive (histological detection, culture, the polymerase chain reaction (PCR), smear examination) or non-invasive (serology, 13C-urea breath test). These tests vary in their sensitivity and specificity, and the choice of test will depend on the situation, for example, whether the test is to detect infection or the success of eradication treatment. The accuracy of histological tests depends, to a large degree, on the expertise of the pathologist, while the accuracy of culture can depend on the conditions in which the specimen is transported and processed. When performed under optimal conditions, both techniques give very good results. The PCR test has similar sensitivity and specificity to histological and culture tests but a strict protocol must be followed to avoid contamination with H. pylori DNA. The rapid urease test (with a reading taken 1 hour later) is suitable for diagnosis before treatment but its sensitivity decreases after treatment. Smear examination has limited sensitivity. The urea breath test and serology (specific IgG detected by enzyme-linked immunosorbent assay with purified antigens) have sensitivities close to those using the best of the biopsy methods. Other points to consider when selecting a test are its availability, the rapidity of the results (which can range from a few minutes to 2 weeks), possibilities for retrospective analysis, quantification and the detection of pathogenic properties, the globality of certain tests that present an overall picture of the stomach, thus avoiding errors in sampling, and the cost of the test. Important added value can be gained from certain tests: histology allows evaluation of the status of the mucosa, culture allows strain typing and tests for antibiotic susceptibility, and the breath test can confirm successful eradication without endoscopy. When the diagnostic tests are performed correctly, most of them are highly accurate.

Biopsy↗
PubMed2006

Kinetics of tropomyosin denaturation as a predictive model for verifying thermal processing of beef products.

An enzyme-linked immunosorbent assay (ELISA) was developed to study thermal denaturation of tropomyosin (Tm) using the time-temperature requirements for cooked beef. The ELISA employed a monoclonal antibody (MAb 2C9) raised against bovine Tm for quantifying residual Tm in muscle extracts. The specificity of MAb 2C9 to bovine Tm was demonstrated by Western blot and the analytical validity of ELISA was confirmed by dot blot. Thermal denaturation of Tm, in the temperature range between 54.4 and 70.0 degrees C, showed first-order dependency. Kinetic parameters of Tm denaturation were derived from isothermal heating of beef muscle extract at 54.4, 57.2, 60.0, and 62.8 degrees C. Temperature dependency of the rate constant (k) was demonstrated by Arrhenius plot; the activation energy (E(a)) of Tm denaturation was determined to be 484 kJ x mol(-1). A mathematic model describing the impact of the heating time-temperature on Tm denaturation was developed. Predicted Tm from the integrated time-temperature model agreed closely with the measured Tm in dynamically heat-processed beef samples. Percent errors between the measured and the predicted values ranged from -5.1 to 5.3%. The kinetic model provides an accurate and reproducible prediction of the impact of actual heating time-temperature on residual Tm in cooked beef. The MAb-based ELISA and kinetic model developed in this study have the potential to be adapted by the meat industry as a quality control tool.

Animals↗
PubMed2004

Comparison of three fecal steroid metabolites for pregnancy detection used with single sampling in bighorn sheep (Ovis canadensis).

We conpared three fecal steroid metabolite assays for their usefulness in detecting pregnalcy among free-ranging Rocky Mountain bighorn sheep (Ovis canadensis canadensis) from Bighorn Canyon National Recreation Area, Wyoming and Montana (USA) and captive bighorn ewes at ZooMontana in Billings, Montana. Fecal samples were collected from 11 free-ranging, radio-collared bighorn ewes in late January-May 2001 and from 20 free-ranging, radio-collared ewes in late March to mid-May 2002. Free-ranging ewes were monitored the following spring to determine whether or not they lambed. In addition, two captive ewes were studied at ZooMontana. With three exceptions, free-ranging bighorn ewes that produced lambs had nonspecific progesterone metabolite (iPdG) levels of >1800 ng/g feces and iPdG levels >7000 ng/gm feces when samples were collected between early March and mid-May. Samples collected earlier in the year were inconclusive. One false negative was suspected to be the result of sample collection error. Of the captive ewes, nonspecific pregnanediol-3alpha-glucuronide (PdG) and iPdG followed a predictable curve over the course of the 180-day pregnancies. We conclude that estrone conjugates are not useful in diagnosing pregnancy; however, fecal steroid analysis of PdG and iPdG can be used to accurately determine pregnancy and reproductive function in bighorn sheep. This holds great potential as a noninvasive technique for understanding the role of reproductive disease in wild bighom sheep.

Animals↗
PubMed2002

Three-year experience in using total laboratory automation system.

We implemented a total laboratory automation (TLA) system, currently used in Chungnam National University Hospital (CNUH), designed around the A&T Corporation to perform the general and specific laboratory testing throughout the system in a timely and cost-effective manner. The system consists of two major lines: chemistry and hematology. The analyzers attached to the hematology line include one SE 9000 hematology analyzer (Sysmex Corporation, Kobe, Japan), one SP-100 slide maker (Sysmex), and one R9000 reticulocyte counter (Sysmex). The chemistry line consists of preanalytic system and linked analyzers. The analyzers attached to chemistry line are one Hitachi 747 chemistry analyzer (Hitachi, Ltd., Tokyo, Japan), one A&T 502X analyzer (A&T Corporation, Tokyo, Japan) and one Architect i2000 immunochemistry analyzer (Abbott Diagnostics Division, Santa Clara, USA). The preanaytic system including start stocker, centrifuge, de-cap unit and aliquoting unit were connected with analyzers. The turn around time (TAT) of all tests was shortened in comparison to manual systems. Consequently it makes feasible one-day care clinic and makes reduced inherent errors in sample identification, dispensing, and reporting. In addition, real-time re-run can make test quality more reliable. As many as 12 departments can be reduced to 7 departments. The subsidiary advantages of smaller size were incorporated into reduced working steps facilitating workflow. Overall, better qualified and quicker results can be provided to the clinicians, and proper cost-effectiveness and better quality services can be anticipated as a result of much easier system management and higher reliability. In conclusion, the TLA has been successful within our laboratory.

Automation↗
PubMed1955

EXPERIMENTAL studies of vaccination, allergy, and immunity in tuberculosis. I. Design for a research programme.

With the growing popularity of BCG vaccination in tuberculosis control programmes, the tuberculin test has become a widely accepted means of determining the success of vaccination, despite persistent disagreement in scientific circles about the relation between skin sensitivity to tuberculin and acquired resistance to tuberculosis. With little hope today of solving the allergy-immunity problem by studies on human beings, and because of the urgent practical need for guide-lines for international mass BCG campaigns, a research programme in laboratory animals has been patterned on extensive studies of BCG vaccination and post-vaccination allergy in school-children.The programme, composed of a series of separate but interrelated projects, is not primarily concerned with the academic intricacies of the allergy-immunity problem. Rather, it has more directly practical objectives. First, to reproduce as nearly as possible in animals what is now being done in vaccination programmes in human beings, in order to compare, in the two species, the responses that are readily observable in man. Secondly, by challenging the vaccinated animals with virulent organisms, to study the association between those responses and resistance to virulent infection. Finally, from the results so obtained, to determine whether and to what extent some observable response to vaccination can be used (by analogy) as a practical guide to the successful vaccination of man.The experimental design takes into account variation in the animals, the vaccines, the challenge infection, and other pertinent factors. Large numbers of animals and randomization procedures have been necessary to ensure that all kinds of variation-biological, sampling, observer errors, etc.-are reduced to a minimum and distributed by chance among the various experimental groups. Observations and techniques common to the projects so far undertaken in the programme are described in the last section of the paper.

Animals↗
PubMed2004

[Evaluation for degree of malignancy and prognosis of patients with brain glioma using 99Tcm-MIBI brain SPECT].

BACKGROUND & OBJECTIVE: It is important and useful to evaluate the degree of malignancy for therapeutic scheme and prognosis evaluation. Traditional imaging methods such as CT and MRI play the important role in distinguishing glioma, but sometimes it was still difficult to diagnose accurately only having the aid of these anatomic information. Stereotaxic needle biopsy is an invasive method and indicates only local pathologic change, sometimes the error of sample collection will result in inaccurate grading. 18F-FDG PET can reflect the glucose metabolic rate of tumor directly and is thought as the most useful method, but the cost is too high so that it cannot be used widely at present. This study measured (99)Tc(m)-MIBI uptake in the patients with different pathological types using (99)Tc(m)-MIBI brain scan and evaluated the malignant degree of astrocytoma and its prognosis. METHODS: Fifty-two patients with glioma and 15 collators were retrospectively analyzed. (99)Tc(m)-MIBI was injected into each patient via elbow vein. SPECT was performed 20 min(early phase) and 2 h (delayed phase) after injection. (1)Diagnostic indices such as sensitivity, specificity, and accuracy were calculated. (2) The tumor to non-tumor ratios (T/N) were calculated according to ROI and compared between groups of different malignancy grading by t-test. (3) The survival time (by means of mean survival time, MST) after (99)Tc(m)-MIBI brain SPECT was follow-up surveyed. According to T/N ratios, the patients were divided into four groups. The MST was compared between four groups by t-test. RESULTS: (1) Among 52 cases of glioma, 44 showed positive and 2 collators showed false-positive on (99)Tc(m)-MIBI SPECT and the sensitivity, specificity, and accuracy were 84.6%, 86.7%, and 85.1%,respectively. (2) On early phase and delayed phase,when T/N ratio was compared, there was no significant difference between grade-I astrocytoma and grade-II astrocytoma (P >0.05), nor was between patients with ependymocytomas and patients with oligodendrogliomas (P >0.05). There was significantly different between every other two groups (P< 0.001),showing the higher the malignancy of astrocytoma,the more the T/N ratio. (3)Comparison of MST indicated that the more the T/N ratio, the shorter the MST. MST in group with T/NT ratio of 1.2-2.0 was significantly longer than that in group with T/NT ratio of 4.1-(t=5.412,P< 0.001) and that in group with T/N ratio of 3.1-4.0(t=4.418,P< 0.001). MST in group of 2.1-3.0 was significantly longer than that in group of 4.1-(t=3.382, 0.002< P< 0.005) and that in group of 3.1-4.0 (t=2.389,0.02< P< 0.05). MST showed no significant difference between the group of 1.2-2.0 and the group of 2.1-3.0 (t=1.691,P >0.05), nor did between the group of 3.1-4.0 and group of 4.1-(t=1.629,P >0.05). CONCLUSION: As a noninvasive technique, (99)Tc(m)-MIBI brain SPECT is effective to diagnose brain glioma and distinguish its malignancy degree. This method, by monitoring the T/N ratio closely, is useful to discriminate tumor viability and determine the prognosis of patients.

Adult↗