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PubMed1996

Novelty-associated locomotion: correlation with cortical and sub-cortical GABAA receptor binding.

The present study was designed to determine whether variability in GABA (eta-aminobutyric acid)A receptor binding in cortical and subcortical brain regions was correlated with locomotor activity in a novel environment. Twenty four animals were rated for locomotor activity in a novel circular runway. Eight days later, locomotor activity was assessed following 1.5 mg/kg amphetamine sulfate (i.p.). After four to six days, animals were killed and samples were pooled in groups of four animals ranked according to novely locomotor score, and specific binding of the GABAA receptor antagonist [2-(3'-carboxy-2'-propyl)-3-amino-6-p-methoxy phenylpyridazinium bromide] ([3H]SR95531) was determined. Significant negative correlations were seen between specific ([3H]SR95531) binding and novelty induced locomotion in the cingulate and prefrontal cortices, and in the ventral pallidum. A near-significant negative correlation was seen in the striatum. Correlation coefficients between locomotion scores in the novel environment and specific [3H]SR95531 binding were: cingulate cortex, R = -0.91, P = 0.012; prefrontal cortex, R = -0.85, P = 0.032; ventral pallidum, R = -0.85, P = 0.030; striatum, R = -0.73, P = 0.097; and nucleus accumbens, R = -0.09, P = 0.85. The positive correlation between novelty- and amphetamine-induced locomotion was also quite high (R = 0.95, P = 0.004). These results are discussed in terms of their relevance to potential biochemical correlates of drug abuse vulnerability.

Animals↗

PubMed1984

Eye tracking impairment: attentional and psychometric correlates in psychiatric patients.

The correlations between eye tracking and a set of attentional and psychometric correlates of psychopathology were studied in groups of schizophrenic, nonschizophrenic psychotic, schizotypal, and neurotic patients (DSM-III criteria), and in a normal control group. Measures of overall and of optimum eye tracking performance were employed. Attentional measures were: reaction time, crossover phenomenon, omission score on the continuous performance test, and amplitude of the contingent negative variation. Psychometric measures were: psychoticism, extraversion, and neuroticism. A measure of eye tracking based on the best cycle in the total sequence proved superior to the overall score as a correlate of psychopathology. The correlational patterns differed widely between groups. Most conspicuous were the correlations of eye tracking with psychoticism in psychotics, especially in schizophrenics, and the impressive number of significant correlations with attentional as well as psychometric variables in the schizophrenic category.

Adult↗

PubMed1989

Correlation of plasma lipid fractions with colorimetrically determined glycated hemoglobin in a nondiabetic population.

To evaluate the incidence of protein glycation (measured as glycated hemoglobin) on plasma lipid levels in a free-living population, a colorimetric method has been used to detect 5-hydroxymethylforfural (HMF) released from glycated hemoglobin (GHb) and enzymatic methods have been used to evaluate total cholesterol, high-density lipoprotein (HDL) cholesterol, fasting glycemia, and total plasma triacylglycerides. These results have been used to calculate low-density lipoprotein-(LDL) cholesterol levels with the Friedewald formula. Results show that a positive correlation exists in men, but not in premenopausal women, between GHb and fasting glycemia (P less than 10(-14], GHb and total plasma cholesterol (P less than .001), GHb and LDL cholesterol (P less than .0001), and GHb with the atherogenic index total/HDL cholesterol (P less than .0001), whereas a negative correlation was shown between GHb and HDL cholesterol (P less than .05). Fasting glycemia does not correlate with cholesterol lipoprotein fractions, but correlates well with total triacylglycerides. These correlations are significant when they are adjusted by age and body mass index. It has also been observed that the positive correlation between glycation of hemoglobin and total cholesterol occurs constantly at all glycohemoglobin levels, and affects all cholesterol fractions analyzed. This suggests an increased atherogenicity with increasing glycohemoglobin levels. Comparisons between groups with high and low GHb levels show variations in the order of 6.5% of total cholesterol levels and a major proportion in the different cholesterol fractions. The higher-range "glycated" populations show total cholesterol, LDL cholesterol and HDL cholesterol values significantly different from the lower-range "glycated" population.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1995

The correlation between transperineal sonography and digital examination in the evaluation of the third-trimester cervix.

OBJECTIVE: To determine the correlation between transperineal or translabial ultrasound and digital examination of the cervix in the third trimester in women presenting to the obstetrical triage area complaining of uterine contractions and/or rupture of membranes. METHOD: One hundred women were evaluated initially with an ultrasound unit using a 5-MHz glove-covered curvilinear transducer applied to the perineum in the sagittal plane. Immediately after the ultrasound evaluation, another examiner assessed the cervix digitally, blinded to the sonographic results. Cervical dilatation, length, and station were assessed. RESULTS: Transperineal ultrasound correlated (P < .001) with digital cervical examination in the assessment of dilatation (Pearson correlation coefficient 0.87), length (Pearson correlation coefficient 0.80), and corrected station (Pearson correlation coefficient 0.69). CONCLUSION: There is a statistically significant correlation between the digital cervical examination and the sonographic assessment of cervical dilatation, length, and station by the transperineal approach.

Adult↗

PubMed1994

Expression of p53, transforming growth factor alpha, epidermal growth factor receptor, and c-erbB-2 in endometrial carcinoma and correlation with survival and known predictors of survival.

Abnormal expression of p53, transforming growth factor alpha (TGF alpha), epidermal growth factor receptor (EGFR), and c-erbB-2 occurs in a variety of cancers and in some cases is associated with poor prognosis. Immunoperoxidase staining using these markers in formalin-fixed, paraffin-embedded endometrial carcinoma tissue was performed to determine whether immunoreactivity correlates with survival and known prognostic variables. Cases included 84 endometrioid adenocarcinomas, five adenoacanthomas, 12 adenosquamous carcinomas, 11 serous carcinomas, 15 clear cell carcinomas, and one carcinosarcoma for a total of 128 cases. Frequencies of immunoreactivity were as follows: p53, 37 of 128 (29%); TGF alpha, strong (2+) 23 of 128 (18%) and intermediate (1+) 26 of 128 (20%); EGFR, strong (3+) 21 of 128 (16%) and intermediate (2+ or 1+) 83 of 128 (65%); and c-erbB-2, strong (2+) four of 128 (2%) and intermediate (1+) three of 128 (1%). p53 and TGF alpha staining showed statistically significant correlations with decreased length of survival (P < .0017 and P < .0013, respectively, generalized Savage [Mantel Cox]). p53 immunoreactivity correlated with tumor types, grade, and stage. Transforming growth factor alpha staining correlated with increased depth of invasion and presence of vascular invasion. Epidermal growth factor receptor staining did not correlate with length of survival or known prognostic variables. c-erbB-2 staining correlated with tumor type. In the multivariate analysis p53 and TGF alpha staining were not independent predictors of survival when other variables were taken into account, including grade, stage, tumor type, presence of vascular invasion, and depth of invasion. Grade and stage were the only independent predictors of survival when used in combination in a Cox proportional hazards model.

Biomarkers, Tumor↗

PubMed1994

Reproducibility of mean nuclear volume and correlation with mean nuclear area in breast cancer: an investigation of various sampling schemes.

Previous studies have shown that quantitative, histopathologic features obtained from a carefully selected area in the tumor section ("selective" approach) have a strong prognostic value in breast cancer. On the other hand, it was found that mean nuclear volume estimation in the whole area of the tumor section by means of "unbiased" stereologic techniques is of great value in predicting the clinical outcome as well. In the present study the results of the two different (ie, selective and random, systematic) sampling methods in assessing mean nuclear volume have been compared as to their intraobserver and interobserver reproducibility in 22 invasive breast cancer cases. The mean nuclear volume (nuclear vv) was assessed both in the most atypical area (AREA) (selected on morphologic criteria) and in the whole tumor section (TOTAL). Furthermore, the correlation with mean nuclear (profile) area (MNA) was studied. Mean nuclear (profile) area was determined in the AREA only. With bivariate correlation analysis the two sampling methods showed high correlation for the nuclear vv values (range of the correlation coefficient, 0.92 to 0.97). There were no systematic intraobserver differences between the different sampling methods. The results of observer 1 showed higher values, both with the selective and random systematic sampling methods. However, these systematic interobserver differences were small (< 9% of the average value of nuclear vv), much smaller than the variation between the tumors (which was > 60%). The time required for assessments in the AREA was less than that required for the determinations in the TOTAL (average, 10 v 20 minutes) in spite of the similar sample size. This is understandable, as in a sclerotic tumor many fields of vision do not contain cancer nuclei. The time required for MNA determinations in the AREA was longer than for nuclear vv assessments in the AREA (15 v 10 minutes). Nuclear vv and MNA (both assessed in the AREA) were (log distributed) significantly correlated (r = .77). Thus, nuclear vv determination in the AREA is the fastest method, and it is also well reproducible and strongly correlated with nuclear vv assessed in the TOTAL. In invasive breast cancer assessments in the whole tumor section can be used if delineation of the measurement area cannot be done easily. In small areas with a limited number of nuclei (eg, microinvasive parts) MNA can be easier to assess than nuclear vv. Further studies are required to compare and evaluate the prognostic value of nuclear vv and MNA.

Breast Neoplasms↗

PubMed1991

Immune parameters in a population of institutionalized elderly subjects: influence of depressive disorders and endocrinological correlations.

Twenty-six institutionalized elderly subjects, selected as healthy according to the SENIEUR protocol, were compared to adult controls to establish correlations between affective disorders and immune abnormalities and to investigate underlying neuroendocrine mechanisms. After an extensive psychodiagnostic examination, 35% of the aged subjects were classified as depressed. Cutaneous delayed hypersensitivity tests showed reduced responses in the aged, but no correlation was found with the psychological status. Examination of the peripheral blood lymphocyte subsets revealed no imbalance in the percentages of CD3+, CD4+, CD8+ cells in the aged. A slight reduction in the CD4+/CD8+ cell ratio could however be detected in the non-depressed aged, as compared to adult controls. The CD4+/CD45R+ cell subset was reduced in non-depressed aged. The percentage of B lymphocytes was reduced in the aged, mostly in the non-depressed subjects. No changes were detected in the percent of OKDR+ cells. The percentage of CD16+ cells was found unchanged, while that of Leu7+ cells was significantly higher in the aged than in the adults and in the non-depressed than in the depressed aged. Leu7+ cell levels were negatively correlated with the depression score. On double labelling, the percent of CD16+/Leu7+ cells appears increased in the subgroup of depressed aged and positively correlated with age. Plasmatic and urinary cortisol levels were both positively correlated with depression score. Urinary cortisol level was higher in the depressed aged. These parameters, as well as plasmatic ACTH, beta-endorphin and urinary catecholamines, were not correlated with immune responses. Based on these findings, we recommend that the neuroendocrinological conditions should be taken into account when healthy subjects are examined in studies of immune senescence.

Aged↗

PubMed1989

Is there any correlation between platelet aggregation, plasma lipoproteins, apoproteins and membrane fluidity of human blood platelets?

Fluorescence anisotropy (which is inversely related to membrane fluidity) of gel filtered platelets of 18 normolipemic subjects (20-26 years) was measured after incubation with three different fluorescent probes (DPH, TMA-DPH, and 6-As). These values were correlated to both platelet aggregation parameters after stimulation with ADP (4 microM), epinephrine (10 microM) or collagen (2 micrograms/ml PRP) and to plasma lipids, lipoproteins and apoproteins. Fluorescence anisotropy values after DPH-labeling of platelets were only negatively correlated to TG (p less than 0.05). No correlation was found between fluorescence anisotropy values of DPH, TMA-DPH and 6-As to LDL-C, Lp(a), HDL-C and HDL3-C (p less than 0.01). However, fluorescence anisotropy values of DPH and TMA-DPH were negatively correlated to apoproteins A2 and B (p less than 0.05). No correlations were found between fluorescence anisotropy after DPH labeling and different aggregation parameters. TMA-DPH and 6-As fluorescence anisotropy values are correlated to epinephrine induced stimulation (p less than 0.01).

Adult↗

PubMed1995

The determination and correlation of reproductive parameters of performance-tested Hereford and Simmental bulls.

Purebred Hereford and Simmental bulls (n = 120), managed similarly to bulls in the Ontario Bull Evaluation Program, were evaluated for reproductive parameters. Four diets, equivalent except for the form of dietary fiber, were fed in a growth performance trial. Diet had no direct effect (P > 0.10) on any of the reproductive variables examined. Of the 117 bulls that had complete breeding soundness evaluations, 75% were classified as satisfactory potential breeders, 24% as questionable potential breeders and 1% as unsatisfactory potential breeders. The 2 breeds were significantly different (P < 0.05) for several end of test parameters. When controlling for age and weight differences, Herefords had a higher backfat thickness, smaller scrotal circumference, lower paired testicular weight and lower epididymal weight. Semen morphology and motility did not differ (P > 0.10) between the breeds. When examining simple correlations, scrotal circumference was highly correlated with paired testicular weight, moderately correlated with epididymal weight, daily sperm production and extragonadal sperm reserves, and negatively correlated with backfat thickness. Scrotal circumference was not related to backfat thickness when controlling for breed effects. The degree of germinal epithelium loss was moderately and negatively correlated with the percentage of spermatozoa with normal morphology and progressive motility, epididymal sperm reserves and epididymal weight, but was not correlated with scrotal circumference.

Journal Article↗

PubMed1987

Allogenotypes defined by short DQ alpha and DQ beta cDNA probes correlate with and define splits of HLA-DQ serological specificities.

HLA-DR and -DQ serotyped cell lines and peripheral blood leucocytes were analysed by Southern blot allogenotyping. Using a short DQ beta cDNA probe, a DQ beta allelic series was defined by restriction fragment length polymorphism (RFLP) with the restriction endonuclease TaqI. This DQ beta allelic series correlates with, and defines splits of, the HLA-DQ serological specificities DQw1 (DQ beta 1a and DQ beta 1b RFLPs), DQw2 (DQ beta 2a and DQ beta 2b RFLPs) and DQw3 (DQ beta 3a and DQ beta 3b RFLPs). By sequential use of a short DQ alpha cDNA probe a second, DQ alpha allelic series is defined by RFLP. This series correlates to a lesser extent than DQ beta RFLPs with the HLA-DQ serological specificities. Thus, two DQ alpha RFLPs correlate with a single DQ serotype (DQ alpha 1a and DQ alpha 1c with DQw1), but three DQ alpha RFLPs correlate with more than one DQ serotype (DQ alpha 1b with DQw1 and DQw3; DQ alpha 2 with DQw2 and DQw3; DQ alpha 3 with DQw2 and DQw3). Individual DQ beta and DQ alpha RFLP subtypes appear to correlate with single, or associated HLA-DR specificities. Specific combinations of DQ beta with DQ alpha RFLPs also correlate with HLA-Dw splits of DR2 and DRw6. A system for HLA-DNA typing is described, which uses RFLP patterns generated by sequential hybridization of TaqI-digested DNAs with short DR beta, DQ beta and DQ alpha cDNA probes. The DQ beta and DQ alpha probes not only identify the DQ allele, but because of linkage disequilibrium with DR, help to assign the DR allele, which may not always be identified with a DR beta probe alone.

Alleles↗

PubMed1995

A method for detecting the time course of correlation between single-unit activity and EMG during a behavioral task.

The chance that a change in excitability of one neuron leads to a change in excitability of another is likely to vary within a single volitional act. This temporal variability in functional connectivity is impossible to assess with standard analytical procedures to accurately that measure the correlation between such elements. This reports describes a technique designed to overcome this limitation by expressing a correlation measure calculated repeatedly in short epochs throughout a behavioral trial. The activity of two elements, a motor cortical neuron and a shoulder muscle, that might take place during a drawing task was first simulated so that the correlation could be manipulated. Various correlation algorithms (standard cross-correlation, spike-triggered average, impulse-response function, impulse-response surface) were tested with these data. Spike trains from a monkey's motor cortex and rectified EMG from its posterior deltoid muscle were compared using the same techniques and shown to have a correlation that changed in a characteristic manner throughout a task that required the monkey to draw a sinusoid.

Algorithms↗

PubMed1989

Correlated firing of retinal ganglion cells.

Even in the absence of visual stimulation, retinal ganglion cells have a substantial maintained discharge. This maintained discharge is not generated independently within each ganglion cell, because the unstimulated activity of two neighboring ganglion cells can be remarkably correlated. These correlations show that two such cells respond together to strong, spontaneous signals from more distal retinal neurons and that, in some cases, ganglion cells even have effects on each other. Observations of correlated firing can give insights not only into the sources of maintained activity but also into retinal connections and signal processing. Correlating firing at the retinal level also has important implications for the use of correlation analysis to study connections between cells in higher visual centers. Much recent attention has focused on the role that correlated firing may play in forming appropriate, ordered connections to a target structure.

Action Potentials↗

PubMed1994

Variations in base pair composition and associated long-range correlations in DNA sequences--computer simulation results.

Recently, the possible occurrence of long-range correlations between nucleotides in DNA sequences of living organisms has excited considerable interest. Of particular importance is the claim that only intron-containing sequences exhibit these correlations. Different investigations, however, have disproved the claimed difference between intron-containing and intron-less DNA sequences. Moreover, very recent investigations pointed out that the long-range correlations appear only if relatively large variations in nucleotide composition along the DNA sequence are present. Furthermore, some examples demonstrated that these variations may have clear biological reasons. In this paper we investigate in detail, with the aid of computer simulations, the connection between compositional heterogeneity of a DNA sequence and the appearance of long-range correlations. As an explicit example, the DNA sequence of the lambda-phage is compared with different artificial sequences of similar compositional heterogeneity. The results demonstrate that the variations of the nucleotide composition along the sequence can fully account for all properties of the claimed long-range correlations. New results of extensive computer simulations are presented which clearly demonstrate how the apparent 'fractal' (or 'long-range-correlated') character of a sequence gradually evaporates, as the frequency of the compositional variations of a simulated sequence continuously increases.

Bacteriophage lambda↗

PubMedDate not supplied

Cross-correlation and latency compensation analysis of click-evoked and frequency-following brain-stem responses in man.

Cross-correlation (CC) and latency compensation (LC) analysis were applied to the human click-evoked brain-stem auditory evoked response (BAER) and the brain-stem frequency-following response (FFR). FFRs were elicited by pure tone stimuli (230 Hz and 460 Hz) or by complex tones derived from the sum of 3rd (920 Hz), 4th (1150 Hz), and 5th (1380 Hz) harmonics of the missing 230 Hz fundamental. The lower and upper harmonics always began in sine phase, while the middle harmonic varied in starting phase, resulting in harmonically complex stimuli with differing amplitude and phase patterns. Cross-correlations were computed between individual trials and a wave form template (smoothed wave V for BAER, pure tone stimulus sinusoids for FFR). Trials were included in the analysis only if values of r2 exceeded 0.5 (negative values of r were thus included, which controlled for the chance occurrence of positive correlations). Although brain-stem recordings are noisy, requiring as many as 1000 stimuli/average, correlation analysis consistently identified more positive than negative trials (approximately 2:1 ratio). Trials were also deleted if the lag associated with the selected r2 was at the maximum shift position ('extreme lag'). Averaging trials that satisfied the correlation and lag criteria led to sizeable enhancement of BAER (mean = 114%) and FFR (mean = 68% for 230 Hz stimulus) amplitudes. LC analysis resulted in additional, albeit smaller, increases in amplitude (approximately 10%). FFRs to harmonically complex stimuli were characterized by a clear periodicity at the missing fundamental frequency (230 Hz). However, amplitudes varied according to the modulation depth of the stimulus and, in certain cases, actually exceeded that of the FFR response to a 230 Hz pure tone. The results demonstrate the effectiveness of cross-correlation and, to a lesser degree, latency compensation analysis, applied to two classes of brain-stem potentials. It is anticipated that such techniques will prove useful in the study of auditory signal processing at the level of the brain-stem.

Acoustic Stimulation↗

PubMed1994

Correlation of histology and acoustic parameters of liver tissue on a microscopic scale.

The correlation of several acoustic parameters with histological features was investigated in healthy White New Zealander rabbit liver (n = 10). Thin sections (10 microns) were studied by means of a light microscope in combination with a digital image processing system. Adjacent thick sections (250 microns) were studied by means of a custom-designed acoustic microscope. Markers of black silk suture material, that could be identified both optically and acoustically, enabled the spatial correlation of both imaging modalities. Acoustic images were reconstructed from the velocity of ultrasound, the attenuation at the central frequency (30 MHz), the attenuation spectral slope, the backscatter spectral slope and the backscatter at the central frequency. The measurements comprised the frequency range from 10 to 50 MHz, yielding a resolution of approximately 50 microns. From the thin sections (10 microns) the local histological composition was obtained by digital segmentation techniques. The features that were segmented are: the collagen rich fibrous tissue content, the area lumina, the area interstitial spaces, the number density of nuclei and the area parenchymal tissue. Correlation techniques revealed that the main feature responsible for attenuation is collagen. There was a fair correlation between area lumina and attenuation, but this was caused by a high correlation between the collagen that surrounds the lumina, and attenuation. No correlation was found between any histological feature and backscatter parameters or velocity.

Animals↗

PubMed1996

Temporal correlation of blood scattering signals in vivo from radiofrequency intravascular ultrasound.

One limitation encountered using high frequency intravascular ultrasound (IVUS) is the echogenicity of blood, which increases dramatically at frequencies of 20-40 MHz. Because of the higher velocity of moving blood particles, the echo pattern of flowing blood shows more variations in time than that of the wall. To investigate the time-varying characteristics of the blood scattering measurements were performed on the radiofrequency (RF) data collected in vivo from five pig experiments. After positioning the echo catheter inside the iliac artery, an M-mode sequence of 30 RF traces was acquired at a high pulse repetition rate (5 kHz). The RF correlation time was measured on the regions of blood and the arterial wall. Two processing techniques, temporal averaging and correlation, were tested for suppression of the blood echo intensity. The correlation time Tc measured in the blood region was approximately 1 ms, which was shorter than that measured in the wall region (Tc >> 6 ms). The correlation values calculated in a small window showed a large variation in the blood region while the wall region produced a constant high output. After processing eight consecutive RF traces (delta T = 200 microseconds), the temporal averaging method results in a 50% intensity reduction in the blood region. Using the correlation output as a weighting function, the blood echo intensity can be further reduced to only 10% of its original value. Application of the RF correlation processing to a cross-sectional image data demonstrates the feasibility of this technique to remove most of the blood echoes and enhance the image contrast of the luminal interface.

Animals↗

PubMed1993

The correlation of response with plasma pharmacokinetics and polyamine concentrations in patients with acute myelogenous leukemia receiving amonafide.

We have investigated the correlation of clinical responses (decreases of white blood cells and peripheral blasts) with pharmacokinetic and pharmacodynamic parameters in patients with acute myelogenous leukemia who are receiving amonafide. The increase of plasma polyamine concentrations was used as a measure of tumor sensitivity (pharmacodynamic effect). The correlations between pharmacokinetic parameters (biological half life, area under the concentration time curve (AUC), total plasma clearance), decreases of total white blood cells and peripheral leukemic blasts were weak (maximum r = 0.47). Correlations of response with polyamines were better than those with pharmacokinetic parameters, but not exceptional; of these, the best correlations were with the increase of putrescine. On the other hand, correlations of combinations of AUC and increases of plasma polyamine concentrations with decreases of total white blood cell counts approached unity. Unexpectedly, decreases of peripheral leukemic blasts were correlated just as well with putrescine increase alone (r = 0.91, P = 0.003) or with a combination of polyamine increases and AUC (r = 0.92, P = 0.036).

Adenine↗

PubMed1991

A possible indicator of functional pain: poor pain scale correlation.

We studied correlations of pain measures in patients with either inflammatory bowel disease (IBD), a disease with a clear organic cause, or irritable bowel syndrome (IBS), a functional pain syndrome in which there is little demonstrable pathology. Correlations were determined between measures on the visual analogue scale (VAS) and on the McGill Pain Questionnaire (MPQ). The VAS score and present pain intensity scale (PPI) of the MPQ correlated well in the organic IBD but correlated poorly in the functional IBS. Differences in correlation between the VAS and PPI scores in functional versus organic disease did not appear to be due to altered sensory and affective pain components. This finding is similar to what we observed in our previous study of organic and functional pain syndromes in the musculoskeletal system. Correlations between the other measures are also discussed.

Chronic Disease↗