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At least 235 records · Page 13Linked to original sources
PubMed1994

Genetic diversity in human Fc receptor II for immunoglobulin G: Fc gamma receptor IIA ligand-binding polymorphism.

Fc gamma receptors, and in particular genetic variation in these receptors, are important in disorders of hose defense, immunohematologic disease, and systemic autoimmune diseases. We investigated the His-Arg (CAT/CGT) polymorphism at codon 131 of the Fc gamma receptor IIA gene, which influences ligand binding by the receptor. Previously, individuals had been classified phenotypically on the basis of differential binding of murine immunoglobulin G1, but the Fc gamma receptor IIA genotype distribution has not been reported. We used selective PCR-based sequence analysis of genomic DNA to determine the distribution in healthy individuals. For African-Americans, the genotype distribution was determined to be A/A (14%), A/G (60%), and G/G (26%); for Caucasian Americans, the distribution was A/A (30%), A/G (51%), and G/G (19%). These data correlate well with phenotypic data. We implemented a nonradioactive single-stranded conformational polymorphism analysis to rapidly identify all three genotypes. The PCR-single-stranded conformational polymorphism analysis method will facilitate studies of the genotype distribution in individuals with disorders of immune function.

Base Sequence↗
PubMed2005

Prognostic role of a multigene reverse transcriptase-PCR assay in patients with node-negative breast cancer not receiving adjuvant systemic therapy.

PURPOSE: To test the ability of a reverse transcriptase-PCR (RT-PCR) assay, based on gene expression profiles, to accurately determine the risk of recurrence in patients with node-negative breast cancer who did not receive systemic therapy using formalin-fixed, paraffin-embedded tissue. A secondary objective was to determine whether the quantitative RT-PCR data correlated with immunohistochemistry assay data regarding estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status. PATIENTS AND METHODS: We obtained archival paraffin-embedded tissue from patients with invasive breast cancer but no axillary lymph node involvement who had received no adjuvant systemic therapy and been followed for at least 5 years. RNA was extracted from three 10-microm-thick sections. The expression of 16 cancer-related genes and 5 reference genes was quantified using RT-PCR. A gene expression algorithm was used to calculate a recurrence score for each patient. We then assessed the ability of the test to accurately predict distant recurrence-free survival in this population. RESULTS: We identified 149 eligible patients. Median age at diagnosis was 59 years; mean tumor diameter was 2 cm; and 69% of tumors were estrogen receptor positive. Median follow-up was 18 years. The 5-year disease-free survival rate for the group was 80%. The 21 gene-based recurrence score was not predictive of distant disease recurrence. However, a high concordance between RT-PCR and immunohistochemical assays for estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2 status was noted. CONCLUSIONS: RT-PCR can be done on paraffin-embedded tissue to validate the large numbers of genes associated with breast cancer recurrence. However, further work needs to be done to develop an assay to identify the likelihood of recurrent disease in patients with node-negative breast cancer who do not receive adjuvant tamoxifen or chemotherapy.

Adult↗
PubMed1977

Analysis of left ventricular function from multiple gated acquisition cardiac blood pool imaging. Comparison to contrast angiography.

Global ventricular function was evaluated by both multiple gated cardiac blood pool scans (MUGA) and contrast ventriculograms in a group of 17 patients with suspected coronary artery disease. The contrast ventriculograms were analyzed frame by frame to generate a volume versus time curve for each patient, while the tracer data were analyzed by two methods: 1) the standard method, in which the left ventricle is identified on the end-diastolic frame and the background corrected activity under the region of interest obtained from the entire cardiac cycle, and displayed as a time versus activity curve; and 2) by a semi-automatic method in which the computer applies a threshold detection program to define the ventricular borders, and activity in the chamber at each point in the cardiac cycle is defined after background correction. The tracer data in each patient were analyzed independently by four observers. The tracer data correlated with the contrast data on a point by point basis r = 0.87 for the standard method, and 0.93 for the semi-automatic technique. An F test of variance revealed the semi-automatic method superior to the standard approach (P less than 0.05).

Computers↗
PubMed2004

Rb+ flux through hERG channels affects the potency of channel blocking drugs: correlation with data obtained using a high-throughput Rb+ efflux assay.

The nonradioactive Rb+ efflux assay has become a reliable and efficient high-throughput hERG screening method, but it is limited by its low sensitivity for potent hERG blockers. Using the patch clamp technique, the authors found that the low sensitivity is due in part to the use of Rb+ as the permeating cation in the assay. The affinities of the drugs measured by patch clamp technique in the presence of Rb+ were 3- to 10-fold lower than when measured by the same method in the presence of K+ ions. The apparent affinity of the drugs decreased even further when monitored by the Rb+ efflux assay. It was also observed that Rb+ had minimal effects on the activation properties of channels while there was a significant change in the half-inactivation potential. This voltage shift reduces hERG channel inactivation at efflux assay potentials, and will reduce the affinity of hERG-blocking drugs that bind to inactivated states of the channel. In combination with the effects of elevated extracellular ion concentrations, it is likely that Rb+ modulation of hERG channel inactivation is largely responsible for the reduced drug potencies observed in the Rb+ efflux assay.

Biological Assay↗
PubMedDate not supplied

Correlation of data from the strain A mouse bioassay with long-term bioassays.

Fifty-nine chemicals that had completed National Cancer Institute rat and mouse 2-year carcinogenicity tests were tested in the strain A mouse pulmonary tumor assay. Without knowledge of chemical identity, 53 chemicals were tested in strain A mice in one laboratory and 30 were tested in a second independent laboratory. Strain A tests on 24 of these chemicals were conducted in both laboratories. The strain A results were generally not predictive of the 2-year rat and mouse carcinogenicity test results. Furthermore, there was poor agreement of strain A results between the two laboratories. Although a variety of explanations may be invoked to explain the lack of concordance between the strain A tests and the 2-year rat and mouse tests, no one factor is sufficient to rationalize the poor concordance between strain A and 2-year carcinogenicity bioassay results.

Animals↗
PubMed1976

[Craniometric studies on the functional morphology of the atlanto-occipital joint in man. Part II. Data and correlations].

Metric and statistical methods were used on a series of skulls (n = 100) to examine the relationship of size and shape parameters of the occipital condyles with other skull variables, which might contribute to an understanding of the morphological variability of occipital condyles and the functional importance of the cranio-vertebral joint (occipital-atlantal-joint) in man. A total of 67 metric variables were included which could be classified into three groups: a) linear measurements, indices and angles of the size and position of the condyles (length, breadth, height and size of the condyles surfaces; length-breadth, length-height and breadth-height indices of the condyles; distance measurements and inclination angles of condyles in the horizontal frontal planes). The size of the condylar surfaces was determined using the printing method of Stofft and Müller. b) Length and breadth measurements and angles of the occipital bone on which the condyles are situated; c) Size circumference, weight and volume measurements of the cranium. The variables of groups b) and c) were mostly taken according to the metrical scheme of Martin. Statistical analysis of the material includes measures of frequency distributions (means, variances, skewness and kurtorsis) and intercorrelations of the variables. Most of the metrical characters of the condyles show high intercorrelations. Similarily, to a large extent highly significant correlations were found between variables of the condyles and length and breadth measurements of pars basilaris and lateralis of the occiput, while little or no statistical association was observed with the size variables of squama occipitalis. The same is true of the correlations between metrical characteristics of the condyles and most of the measurements of the cranium. Likewise cranial capacity and weight of the cranium show little correlation with condylar measurements. Therefore the present study does not support the existence of a relationship between cranial weight or the pressure on the cranio-vertebral joint, and the size and position of occipital condyles as supposed by zoologists on the basis of research work on different species of mammals. However the size and distance measures of the condyles show significant correlations with skull height (basi-bregmatic height) and the length of the skull base (basi-nasal length). The highest correlation coefficient values (r = 0.5) were observed between skull height and the size of the surface of the condyles and the length of the condyles. Somewhat smaller but statistically significant r values were found between basi-bregmatic height of skull and the distance measurement between the condyles. The correlation coefficients demonstrate that skull of greater height possess the condyles which are not only larger and longer but show increased distance between the condyles as well, resulting in a larger supporting area for the skull...

Atlanto-Occipital Joint↗
PubMed2003

[Gathering and evaluation of phenotype data of haemophilia A patients for correlation with genotype data].

Haemophilia A is caused by a genetic defect of the factor VIII gene resulting in complete or considerable functional loss of factor VIII molecule within blood. The high bleeding risk of patients can be prevented by intravenous injections of factor VIII protein. However, 25% of patients affected with severe haemophilia, develop factor VIII antibodies against the concentrate substituted. Within this study we try to comprise the phenotypic parameters (e. g. detailed documentation of disease course, basic laboratory values) and the therapy-associated data (e. g. applicated type and amount of factor VIII, number of substitutions, factor VIII recovery, inhibitor development and inhibitor elimination). We hope to identify differences of variable therapeutic treatments on course of disease as already identified for the factor VIII gene defects. At least we expect that certain mutations and mutation types, respectively, can be referred to typical phenotypes and similar course of treatment protocols.

Databases, Factual↗
PubMed1989

The determination of total haemoglobin as haemiglobin.

This study describes a new method for routine total haemoglobin determination by conversion to haemiglobin (Hi), and compares it with the haemiglobin cyanide (HiCN) method. Experiments were performed in two phases. Firstly, the absorbance coefficient (epsilon Hi,500mm) at pH = 6.8, determined from 24 blood samples, was found to be 998 +/- 31 m2.mol-1. Secondly, using this value of epsilon, the range of haemoglobin concentration measured was 3.7 to 19.2 mmol.l-1 (6 to 31 g.dl-1). The correlation data shows an excellent correlation (r = 0.982, p less than 0.001) with the reference procedure. Reproducibility and accuracy were shown to be good.

Evaluation Studies as Topic↗
PubMed1987

Pupil response as an objective measure of visual acuity.

Pupillary responses to brief presentations of sinusoidal grating patterns were measured. The results show that the amplitude of the pupillary responses varies systematically with grating spatial frequency. Gratings of spatial frequencies in the range 1-5 c deg-1 elicited the maximum percentage change in pupil area, with higher and lower spatial frequency gratings producing smaller responses. The bandpass nature of the pupil response function was compared to contrast sensitivity functions obtained under the same viewing conditions. The effects of defocus and eccentric fixation on both contrast sensitivity and pupil response functions were qualitatively similar. Grating acuities calculated from contrast sensitivity data correlated well with similar data extracted from pupil response functions. The results suggest that automated pupillometry can provide an attractive means for objective measurement of visual acuity.

Fixation, Ocular↗
PubMed1987

Structural and morphometric analysis of parakeratotic and dyskeratotic cells exfoliated from various vulvar lesions. Correlation with data from cervical cytology.

Smears were taken from the vulvar skin of 123 patients (21 with normal-appearing skin and 12 with dystrophic, 29 with benign, 20 with precancerous and 53 with malignant conditions). In each case, 20 nucleated horny squames with the highest visible degree of abnormality were identified in the smear. The cytoplasmic and nuclear structures of these cells were analyzed, and the cytoplasmic and nuclear perimeters were measured by a graphics tablet (digitizing board) equipped with a camera lucida system. Five cytomorphometric parameters were calculated: cytoplasmic and nuclear areas and shape factors and the relative nuclear area. A stepwise multivariate discriminant analysis was used to evaluate the statistical significance of the parameters. Structurally, the cells from different vulvar conditions did not differ much from each other except in the formation of small cellular projections ("pseudopodia"), which were found significantly more frequently in precancerous and cancerous lesions than in others. Nuclear degeneration was a general finding in all examined cases of all conditions. Morphometric analysis revealed cytoplasmic pleomorphism to be the predominant feature associated with increasing degrees of malignancy. There was no significant increase in the relative nuclear area with increasing malignancy because the cytoplasmic and nuclear areas enlarged almost simultaneously. The cellular features found in nucleated horny cells exfoliated from various vulvar lesions are quite different from the well-known attributes of squamous epithelial cells originating from comparable conditions of the uterine cervix.

Cytoplasm↗