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PubMed1990

Intracranial blood flow: quantification with duplex Doppler and color Doppler flow US.

The authors compared changes in cerebral blood flow (CBF), determined by means of injection of radiolabeled microspheres, with Doppler blood flow measurements obtained simultaneously in the middle (n = 9) and anterior cerebral arteries (n = 3) in 12 newborn lambs. Doppler estimates of blood flow and mean blood flow velocity correlated well with changes in CBF. However, with changes in mean blood flow velocity, the degree of change in CBF tended to be underestimated. The resistive index correlated well with perfusion pressure but correlated weakly with cerebrovascular resistance and poorly with changes in CBF. Doppler blood flow estimates and mean blood flow velocities correlate well with changes in CBF and allow significant improvement in accuracy over instantaneous velocity or pulsatility measurements alone. Determination of absolute blood flow remains difficult due to systolic and diastolic differences in vessel diameter and intrinsic error in true diameter measurement with currently available color flow technology.

Animals↗

PubMed2001

Development of an element-selective monitoring system for adsorbable organic halogens (AOX) with plasma emission spectrometric detection for quasi-continuous waste-water analysis.

An automated quasi-continuously-operating monitor has been developed for element-selective analysis of adsorbable organic halogens (AOX) in water. After extensive optimization the automatic method was applied to the analysis of standard solutions and real waste water samples to prove its analytical applicability. The new instrument is based on the element-selective analysis of halogens by means of a spectroscopic detection system consisting of a microwave-induced helium plasma excitation source (TM010-type; developed in this laboratory) and the plasma emission detector (PED) which operates with oscillating narrow-band interference filters. After enriching the organic components on activated charcoal and pyrolysis in an oxygen stream at 950 degrees C, in accordance with DIN/EN 38409,H14/1485, interfering CO2 and H2O gas generated during combustion is removed from the analytes in the so-called ELSA-system (element-selective AOX-analyzer). For focused injection into the plasma excitation source the analytes (hydrogen halides) are trapped in a deactivated fused silica capillary at -180 degrees C; this is followed by identification and quantification on the basis of element-specific emission of radiation in the VIS and NIR-region (chlorine 837.6 nm, fluorine 685.6 nm). Bromine and iodine could not be detected with satisfactory inter-element selectivity, because of spectral interferences caused by matrix elements, and so results from the respective single-element investigations for determination of AOBr and AOI are not presented. The procedure has been validated and the analytical performance has been examined by calibration with p-chlorophenol and p-fluorophenol. The limit of detection was 1.1 microg (absolute) for chlorine and 6.6 microg (absolute) for fluorine.

Flow Injection Analysis↗

PubMed2005

Absolute mRNA levels and transcriptional regulation of the mouse testis-specific thioredoxins.

Thioredoxins function as general protein disulphide reductases. Mammalian male germ cells are equipped with a set of three testis-specific thioredoxins (named Sptrx-1, -2, and -3, respectively) that are expressed either in different structures within the sperm cell or at different stages of sperm development. Previous studies based on qualitative northern-blot and in situ hybridization analyses restricted the presence of Sptrx mRNAs to adult testis, but nothing is known about their transcriptional regulation or relative expression levels in this tissue. In this report, we investigate the transcriptional profiles of the mouse Sptrx genes in terms of the germ cell-specific regulation by promoter analysis in GC-2spd(ts) cells. Besides, we perform a comprehensive quantification of the Sptrx mRNA molecules by real-time PCR in whole-animal experiments. By these means, we show that transcription is differentially regulated for each Sptrx gene and identify the 5'-flanking regions anticipated to contain the cis-regulatory elements responsible, at least in part, for the transcriptional silencing and/or activation of the Sptrx genes. In addition, we show remarkable age-associated variations between the Sptrx mRNA expression patterns.

Animals↗

PubMed1994

Isokinetic evaluation of muscular performance: implications for muscle testing and rehabilitation.

Interfacing of microprocessors with isokinetic dynamometers has enabled the rapid quantification of many parameters of muscle function including peak torque, angle-specific torque, work, power, torque acceleration energy, and various endurance indexes, and the measurements with these devices can be made isometrically at various angular positions and isokinetically (concentrically or eccentrically) with a large scale of angular speeds. Many of these parameters, however, lack evidence of validity, reproducibility, and/or clinical relevance. Peak torque has been and still is the most properly studied isokinetic strength testing parameter and its use can be recommended for research and clinical purposes. Concerning testing of muscular endurance, the absolute endurance parameters (for example, work performed during the last five repetitions and total work in a 25-repetition test with a speed of 240 degrees/s) are the best for use. Many internal and external factors in the isokinetic testing procedure can have an undesirable effect on the test result. However, through proper education and strict adherence to the test instructions, it is possible to successfully control the confounding variables. In scientific work, isokinetic devices have greatly expanded the possibilities for studying dynamic muscle function. There is also little doubt about their usefulness in documenting the progress of muscular rehabilitation. A disadvantage of isokinetic devices is that isokinetic movement seldom occurs in actual human performance tasks and that the isokinetic training effect is, therefore, quite (although not completely) specific to that type of movement. In addition, being normally an isolated joint exercise, isokinetic training can produce large loads on the involved joints and may, therefore, under certain conditions be dangerous for healing tissues.

Biomechanical Phenomena↗

PubMed1980

Thermodynamic technique for the quantification of regional blood flow.

A method is described to quantify regional blood flow by thermal analysis. A weak temperature field is established in a tissue and for a thermal steady state, unidirectional heat flux and the associated temperature gradient are measured simultaneously across a small fixed segment of the tissue. This information is evaluated with probe calibrations for homogeneous isotropic fluids, with data from ancillary measurements in the nonperfused tissue and with values of specific heat and density of blood to express local blood flow in heat transfer [effective thermal conductivity (W. degrees C-1 . cm-1 x 10(-3) and/or in perfusion (ml . min-1 . cm-3)] terms. The technique measures local perfusion in small tissue volumes and is usable in acute or chronic experiments. Its accuracy is not a function of the absolute steady-state temperature of the tissue or of its metabolic heat production.

Animals↗

PubMed2001

Quantification of intrahepatic non-uniform distributions for assessing impaired function of liver using 99Tcm-DTPA-galactosyl serum albumin liver SPECT scintigraphy.

Quantitative evaluation of intrahepatic non-uniform distribution was attempted by functional volumetric analysis of liver single photon emission computed tomography (SPECT) scintigraphy using 99Tcm-diethylenetriaminepentaacetic acid galactosyl serum albumin (99Tcm-GSA) (185 MBq). A total of 148 patients were classified into three groups: diffuse liver disease, liver disease with space-occupying lesions, and non-hepatic disease. The volume obtained at the 10% cut-off threshold from reconstructed liver-specific SPECT images was assumed to be the functional total hepatic volume, and the functional volume rates were calculated every 10% threshold width from 10% to 100%. The hepatic distribution index (D index) was calculated from the sum of absolute differences from the control. The hepatic D index in liver cirrhosis was significantly higher than in hepatitis and other diffuse liver diseases, and the index in liver disease with primary malignant neoplasm was significantly higher than in liver disease with metastasis or a benign-space occupying lesion. Additionally, it was significantly negatively correlated with LHL15, and positively correlated with the clinical severity. However, in stages II and III, with which LHL15 did not significantly correlate, the hepatic D index matched the severity of hepatic impairment. The hepatic D index evaluates distribution of functional hepatocytes and may provide a new clinical method for quantitatively assessing hepatic impairment.

Hepatitis↗

PubMed2006

Phasic changes in arterial blood volume is influenced by collateral blood flow: implications for the quantification of coronary stenosis at rest.

BACKGROUND: The systolic to diastolic arteriolar blood volume (aBV) ratio derived using myocardial contrast echocardiography (MCE) can identify the presence of coronary stenosis at rest. There are some patients with moderate to severe coronary stenosis who nonetheless exhibit a normal systolic to disatolic aBV ratio. AIM: To test the hypothesis that collateral blood flow influences the systolic to diastolic aBV ratio. MCE-defined phasic changes in aBV were recorded at baseline and up to 2 degrees of non-critical stenosis in 12 dogs. Measurements were made from MCE-defined collateralised and non-collateralised portions of the left anterior descending arterial bed. RESULTS: Increases in both systolic and diastolic aBV were noted in the non-collateralised region with increasing degrees of stenosis. Although these increases in the absolute values did not reach statistical significance, the systolic to diastolic aBV signal ratio in the non-collateralised bed increased significantly between stages (analysis of variance, p = 0.003). In comparison, in the collateralised bed neither the absolute systolic nor diastolic aBV signals changed with increasing degrees of stenosis. Consequently, the aBV signal ratio between systole and diastole also did not change in this bed. CONCLUSION: Phasic changes in aBV are influenced by the degree of collateral blood flow. Thus, if the region of interest is not placed in the centre of the vascular bed, the degree of stenosis may be underestimated by the systolic to diastolic aBV ratio. On the other hand, as extensive collateralisation may indicate excellent prognosis, this ratio may provide prognostic information independent of the coronary anatomy.

Animals↗

PubMed1996

Evaluation of the relationship between laboratory and clinical tests of transversus abdominis function.

A clinical test of the function of the deep abdominal muscles was compared to a laboratory electromyographic (EMG) investigation of the contribution of transversus abdominis (TrA) to stability of the lumbar spine during limb movement. The two different functions of TrA were evaluated in 15 subjects. The subject group included six subjects with chronic low back pain and nine subjects with no history of low back pain so that the resultant recordings were spread over a wide range for each test. The clinical test involved quantification of the ability of the subjects to specifically displace the anterior abdominal wall in a way consistent with the function of the muscle. This was evaluated by use of a device designed to measure pressure reduction as the abdomen lifted off a transducer in the prone position. The laboratory test involved determination of the onset of contraction of TrA associated with rapid upper limb movement, measured using fine-wire EMG electrodes. The parameter evaluated was the latency between the contraction of TrA and the prime mover of the limb. Data were analysed both as absolute values and as ordinal data of a three-rating scale derived from criteria based on current knowledge of the response to both tests. No significant correlation was found between the absolute magnitudes of the pressure and timing data, however, comparison of the rating scale data indicated a significant relationship between the tests and associated high level of agreement between the two measures. The results of the study indicate that a reduction in the ability to draw in the abdominal wall is related to changes in the coordination of TrA, although the magnitude of the changes were not correlated. The degree of causality between these co-varying but independent manifestations of the function of TrA is uncertain.

Abdominal Muscles↗

PubMed2003

Role of hepatitis B virus specific cytotoxic T cells in liver damage and viral control.

To understand the role of cytotoxic T cells in liver damage and viral control, we used human histocompatibility leukocyte antigen (HLA)-peptide tetramers that allow direct ex vivo quantification of circulating and liver-infiltrating HBV-specific CD8 cells. Studies were carried out in two groups of patients, one without liver inflammation and minimal HBV replication and the other with liver damage and inflammation along with a high level of viral replication. Contrary to expectation, a high frequency of intrahepatic HBV-specific CD8 cells was found in the former group, i.e., the absence of hepatic immunopathology. In the replicating viraemic group, the virus specific T cells were diluted among the liver infiltrates; although with the massive cellular infiltration that was present, the absolute number was similar. It was also shown that in the low viraemia group the reservoir of CD8+ cells present in the circulation was able to expand after specific virus recognition and that this was not detectable in highly viraemic patients with liver inflammation. These results show that inhibition of virus replication can be independent of liver damage and when the HBV-specific CD8 response is unable to control virus replication it may contribute to liver pathology not only directly but by causing recruitment of non-virus specific T cells.

Alanine Transaminase↗

PubMed1992

Selective downregulation of rat renal clearance receptors for atrial natriuretic peptide by chronic high-salt intake: study on isolated membranes using 125I-labelled c-atrial natriuretic peptide-(4-23).

1. 125I-labelled c-atrial natriuretic peptide-(4-23) was used as radioligand for the direct quantification of atrial natriuretic peptide clearance receptors, and 125I-labelled rat atrial natriuretic peptide-(1-28) was used for the determination of total and biologically active atrial natriuretic peptide receptors, in renal glomerular and papillary membrane preparations of chronically salt-loaded and control rats. 2. The membrane preparation technique included acid-washing (pH 5), and receptor binding was assessed by saturation studies at 4 degrees C for 3 h. Chronic salt loading revealed a 35% decrease in clearance receptor number in the glomerular membrane and a 42% decrease in the papillary membranes. The absolute decrease in clearance receptor number was almost identical with the observed reduction in absolute number of total atrial natriuretic peptide receptors. Biologically active receptors were not affected by chronic salt loading. 3. Selective downregulation of clearance receptors for atrial natriuretic peptide may reflect an important role for the rat renal atrial natriuretic peptide system in long-term fluid and electrolyte regulation.

Animals↗

PubMed2004

Noninvasive quantification of brain edema and the space-occupying effect in rat stroke models using magnetic resonance imaging.

BACKGROUND AND PURPOSE: Brain edema is a life-threatening consequence of stroke and leads to an extension of the affected tissue. The space-occupying effect due to brain edema can be quantified in rat stroke models with the use of MRI. The present study was performed to test 2 hypotheses: (1) Can quantification of the space-occupying effect due to brain edema serve as a noninvasive measure for brain water content? (2) Does morphometric assessment of brain swelling allow determination of true infarct size on MRI after correction for the space-occupying effect of edema? METHODS: Thirty rats were subjected to permanent suture middle cerebral artery occlusion. MRI was performed after 6 or 24 hours, and hemispheric swelling was assessed morphometrically. Interobserver and intraobserver agreements were determined for MRI measurements. In study I, the space-occupying effect due to brain edema was correlated with the absolute brain water content by the wet/dry method. In study II, lesion volumes corrected and uncorrected for edema were calculated on MRI and on TTC staining and compared. RESULTS: Interobserver and intraobserver agreements for MRI measurements were excellent (r>or=0.97). Brain water content and hemispheric swelling correlated well after 6 and 24 hours (r>or=0.95). Corrected lesion volumes correlated with r=0.78 between TTC staining and MRI. Without edema correction, lesion volumes were overestimated by 20.3% after 6 hours and by 29.6% after 24 hours of ischemia. CONCLUSIONS: Morphometric assessment of hemispheric swelling on MRI can determine the increase in absolute brain water content noninvasively and can also provide ischemic lesion volumes corrected for brain edema.

Animals↗

PubMedDate not supplied

Changes in rat heart histomorphometry due to two-week dietary restriction.

In preclinical safety studies in which the administration of a test compound causes reductions in food consumption, body weights, and organ weights, it may be difficult to differentiate direct compound-induced effects on organ weights from those simply due to reduced nutrition. To address this problem in reference to the heart, hearts were obtained from rats that were known to have had reductions in body weights and absolute heart weights as a result of feed restriction. Rats (40/sex) were divided into 4 groups (10/sex) and given quantities of ad libitum diet for 2 wk as follows: Group 1, 100%; Group 2, 75%; Group 3, 50%; and Group 4, 25%. Routine histologic evaluation was performed on longitudinal sections of paraffin-embedded hearts stained with hematoxylin and eosin. Computer-assisted image analysis was conducted on left ventricular free-wall of picrosirius red-stained sections for histomorphometric evaluation of ratio of cross-sectional area occupied by myofibers versus interstitium and for quantification of myofiber width. No differences were detected histologically among groups, and no difference in the mean myofiber: interstitium ratio was detected between Groups 1 (9.1) and 4 (9.5). Mean values for myofiber width ranged from 24.6 microns for Group 1 to 17.3 microns for Group 4. Two-way ANOVA revealed a strong effect of dietary restriction on reduction of myofiber width but no consistent gender effect. The significant dietary effects occurred in Groups 3 and 4 compared to corresponding controls. The present authors speculate that, if reductions in feed intake were < 50% in short-term preclinical studies, any reductions in myofiber width could imply a primary test article effect. Conversely, if reductions in feed intake were > or = 50% in such studies, reductions in myofiber width could be caused either solely by inadequate nutrition or by combined effects of nutrition and test article.

Animals↗

PubMed1997

Simultaneous determination of soluble sugars and organic acids as their trimethylsilyl derivatives in apricot fruits by gas-liquid chromatography.

The aim of this study was to determine a reliable procedure for the quantification of organic acids, alcohol soluble sugars and sugar alcohols in fruit flesh by means of a rapid GLC method, without resorting to methoximation of sugars and employing apricot as a model. The use of two internal standards, an accurate derivatization and a proper calibration of the GLC conditions allowed an accurate quantitative analysis of the compounds detected in the unknown samples. This simple procedure improves the speed of preparation of the trimethylsilyl derivatives and is highly reproducible. Variability was found between years for each of the five cultivars studied and for each compound in terms of absolute values, whereas the percentage incidence of the single sugars as a total was more stable over the two years of observation.

Calibration↗

PubMed2004

Myocardial perfusion measurements by spin-labeling under different vasodynamic states.

In this study absolute myocardial perfusion was determined using a spin-labeling magnetic resonance imaging (MRI) technique at 2 Tesla. The technique was applied to 16 healthy volunteers at resting conditions, adenosine-induced stress, and oxygen breathing. Overall myocardial quantitative perfusion was determined as 2.3 +/- 0.8 mL/g/min (rest), 4.2 +/- 1.0 mL/g/min (adenosine), and 1.6 +/- 0.6 mL/g/min (oxygen), respectively. T1 of left ventricular blood pool decreased from 1709 +/- 101 ms (rest) to 1423 +/- 61 ms (oxygen), whereas T1 of right ventricular blood did not change significantly (1586 +/- 126 ms and 1558 +/- 150 ms). In conclusion, the presented technique for quantification of myocardial perfusion is an alternative to contrast agent-based methods. The spin labeling method is noninvasive and easily repeatable and it could therefore become an important tool to study changes in myocardial perfusion under different vasodynamic states.

Adenosine↗

PubMed2006

Short term culture of breast cancer tissues to study the activity of the anticancer drug taxol in an intact tumor environment.

BACKGROUND: Sensitivity of breast tumors to anticancer drugs depends upon dynamic interactions between epithelial tumor cells and their microenvironment including stromal cells and extracellular matrix. To study drug-sensitivity within different compartments of an individual tumor ex vivo, culture models directly established from fresh tumor tissues are absolutely essential. METHODS: We prepared 0.2 mm thick tissue slices from freshly excised tumor samples and cultivated them individually in the presence or absence of taxol for 4 days. To visualize viability, cell death, and expression of surface molecules in different compartments of non-fixed primary breast cancer tissues we established a method based on confocal imaging using mitochondria- and DNA-selective dyes and fluorescent-conjugated antibodies. Proliferation and apoptosis was assessed by immunohistochemistry in sections from paraffin-embedded slices. Overall viability was also analyzed in homogenized tissue slices by a combined ATP/DNA quantification assay. RESULTS: We obtained a mean of 49 tissue slices from 22 breast cancer specimens allowing a wide range of experiments in each individual tumor. In our culture system, cells remained viable and proliferated for at least 4 days within their tissue environment. Viability of tissue slices decreased significantly in the presence of taxol in a dose-dependent manner. A three-color fluorescence viability assay enabled a rapid and authentic estimation of cell viability in the different tumor compartments within non-fixed tissue slices. CONCLUSION: We describe a tissue culture method combined with a novel read out system for both tissue cultivation and rapid assessment of drug efficacy together with the simultaneous identification of different cell types within non-fixed breast cancer tissues. This method has potential significance for studying tumor responses to anticancer drugs in the complex environment of a primary cancer tissue.

Adenocarcinoma, Mucinous↗

PubMed1989

[The present possibilities of quantitative Doppler echocardiography using pulse and continuous technics. II. Evaluation of cardiac hemodynamics].

The paper presents a clear and concise description of potential ways how to evaluate selected haemodynamic indicators using Doppler echocardiography. The evaluation of the systolic function of the left ventricle is based on the estimate of cardiac flow volumes (i.e. minute and stroke volumes) established by the quantitative Doppler curve speed analysis at the orifice measured. More recent indicators are: peak velocity of aortal ejection, acceleration time or the absolute acceleration value. All the mentioned values can be also obtained during examination at exertion. By means of an analysis of the changes in values and on the basis of the value obtained from the examination at exertion, the authors try to discriminate the patients with a functional (most often ischaemic) myocardial affection of greater or smaller extent. The diastolic function of the left ventricle is evaluated to a certain degree by analyzing its filling using quantitative analysis of speed-time integral of the mitral diastolic flow. Other haemodynamic values obtained by means of speed curve quantification include: estimate of some intracardiac pressures values (systolic pressure in the right ventricle, medial pressure in the pulmonary artery, telediastolic pressure in the left ventricle) and quantification of the intracardiac shunts.

Echocardiography, Doppler↗

PubMed1986

[Doppler sonography quantification of mitral valve stenosis in patients with and without mitral valve insufficiency].

Fifty-three patients with mitral stenosis (MS) were examined by two dimensional (2DE) and Doppler echocardiography (Dop). Twenty-nine of them also had mitral insufficiency (MI) as judged by Dop. The mitral valve area (MVA) was calculated from Doppler using the "pressure half time" and was compared with MVA by 2 DE. There was a good correlation between both methods in all 53 patients (r = 0.88; SEE = 0.34 cm2) but also in the subgroups with pure MS (r = 0.86; SEE = 0.29 cm2) and MS + MI respectively (r = 0.90; SEE = 0.38 cm2). The accuracy and the reproducibility of the Doppler method was highly dependent on the severity of the stenosis. In 19 cases with mild MS (MVA by 2 DE greater than 1.5 cm2) the absolute difference between MVA 2 DE and Dop averaged 0.39 cm2. The difference between the maximal and minimal Doppler MVA which reflects the variability of this method averaged 0.65 cm2 in this group. In cases with significant MS (MVA by 2 DE less than or equal to 1.5 cm2) the average difference 2 DE -Dop and Dop max-Dop min was only 0.20 cm2 and 0.27 cm2 respectively. In patients with comparable degrees of stenosis additional MI did not adversely affect the accuracy of the Doppler method. We conclude that Doppler echo allows an accurate quantitation of mitral stenosis even in patients with associated MI.

Adolescent↗

PubMed2001

Prognostic implications of absolute and relative calcium scores.

BACKGROUND: The continuing epidemic of cardiovascular disease underscores the need for more effective atherosclerosis detection and prevention. In fact, though the mortality rate decreased during the past decades, the morbidity rate continued to climb. The use of conventional risk factors is helpful to assess the median risk of a population, but it is unsatisfactory to estimate the actual risk of an individual patient. MODERN IMAGING TECHNOLOGIES: As a consequence, modern imaging technologies able to detect silent atherosclerotic disease have elicited a strong interest in the medical community with the hope that they may render risk stratification more accurate. Technologies such as electron beam tomography (EBT) are expected to bridge the gap between the mere presence of risk factors for disease development and assessment of the actual individual risk of events based on the visualization and quantification of silent disease. CONCLUSION: The medical literature is currently pervaded by a vivacious debate regarding the ability of EBT to provide such information as some investigators still hold concerns about the cost and effectiveness of a preventive approach driven by technology.

Adult↗