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PubMed1986

Quantitative analysis of tight junctions and the uptake of 99mTc in human gliomas.

The structural dimensions of capillary tight junctions and the uptake of 99mTc pertechnetate in human gliomas were studied. Quantitative analysis revealed a correlation between the uptake of radionuclides and the length of endothelial tight junctions. It is suggested that brain scintigraphy might be used for the selection of malignant brain tumors with altered tight junctions which might be accessible to chemotherapy with water-soluble agents.

Blood-Brain Barrier↗

PubMed1988

[Regional characteristics of the organization of the aortic endothelium (a quantitative analysis)].

By means of SEM-analysis in 110 microphotos (from 14 aortas of white rats) with the aim to estimate heteromorphism of the thoracic part endothelium, quantitative characteristics of endotheliocytes have been studied in the ventral and dorsal surfaces, and also around the ostia of the intercostal arteries. For the quantitative analysis organization of the lines of the interendotheliocyte borders is taken into account. Endotheliocytes around the ostium are more elongated but occupy less area and have less straight contours in comparison with cells in other regions; they have also greater variability. Essential differences in arranging the endothelial cells into the layer on the ventral and dorsal surfaces of the aorta are revealed.

Animals↗

PubMed1987

Genetic architecture and adaptation: quantitative analysis of sheep and refuse tip populations of the Australian sheep blowfly, Lucilia cuprina.

Phenotypic differentiation between geographic areas and between sheep and adjacent refuse tip populations was assessed by quantitative analysis of population samples of L. cuprina from New South Wales (Lismore) and Victoria (Mansfield). In addition the genetic structure of populations has been defined and compared by biometrical analysis techniques. For all morphological and fitness characters examined significant phenotypic differentiation was observed both between geographic localities and between sheep and non-sheep populations of each locality. Diallel analysis of the populations revealed architectural differences between sheep and non-sheep populations for both fecundity and egg hatchability. Sheep populations only, regardless of locality, displayed dominant gene effects on these fitness traits. The results suggest that refuse tip populations may be other than transients and that the differentiation may reflect differing patterns of adaptation and history of selection of the populations. The relevance of such differentiation to the successful establishment of a chemical and/or autocidal control zone is considered.

Adaptation, Physiological↗

PubMed2000

Quantitative analysis of pharmaceutically active peptides using on-capillary analyte preconcentration transient isotachophoresis.

An on-capillary adsorptive phase in combination with capillary electrophoresis (CE), frequently referred to as preconcentration CE, for quantitative analysis of low peptide concentrations was developed. The capillary containing the on-line analyte preconcentrator can be constructed within 5 min from commercially available extraction disks. These disks contain poly(styrenedivinylbenzene) adsorbent particles incorporated in a matrix of inert Teflon, creating a mechanically stable sorbent. Therefore, no frits are needed in the capillary to hold the stationary phase in place. Several parameters, such as the required minimal elution volume, required elution strength, sample application speed or ionic strength, and the capacity were investigated and special interest was given to the quantitative properties of the method. Instead of nL injections, volumes up to a least 25 microL are possible, yielding improvements in detection limits of 3-4 orders of magnitude. The observed limit of detection for both model peptides was 20 pg, corresponding to a 20 microL injection of a 1 ng/mL solution of both model peptides. Using low-wavelength UV detection, reproducibility and linearity in the low nanogram range were satisfactory. No influence of matrix salt concentrations was observed, extending the use of CE to all kinds of samples.

Electrophoresis, Capillary↗

PubMed2004

Simple and sensitive liquid chromatographic quantitative analysis of the novel marine anticancer drug Yondelis (ET-743, trabectedin) in human plasma using column switching and tandem mass spectrometric detection.

The development of a simple and sensitive assay for the quantitative analysis of the marine anticancer agent Yondelis (ET-743, trabectedin) in human plasma using liquid chromatography (LC) with column switching and tandem mass spectrometric (MS/MS) detection is described. After protein precipitation with methanol, diluted extracts were injected on to a small LC column (10 x 3.0 mm i.d.) for on-line concentration and further clean-up of the sample. Next, the analyte and deuterated internal standard were back-flushed on to an analytical column for separation and subsequent detection in an API 2000 triple-quadrupole mass spectrometer. The lower limit of quantitation was 0.05 ng mL(-1) using 100 micro l of plasma with a linear dynamic range up to 2.5 ng ml(-1). Validation of the method was performed according to the most recent FDA guidelines for bioanalytical method validation. The time needed for off-line sample preparation has been reduced 10-fold compared with an existing LC/MS/MS method for ET-743 in human plasma, employing a labor-intensive solid-phase extraction procedure for sample pretreatment. The proposed column switching method was successfully applied in phase II clinical trials with Yondelis and pharmacokinetic monitoring.

Antineoplastic Agents, Alkylating↗

PubMed2001

[Promoter hypermethylation during tumor progression: quantitative analysis employing kinetic PCR].

The methylation of cytosine residues in the promoter region of tumour-suppressor genes is now widely recognised as an alternative mechanism of gene inactivation in cancer. To address the question whether promoter methylation is an early event in the process of malignant transformation and whether quantitative changes are occurring during clonal evolution we developed a new assay for the measurement of cytosine methylation, which could also be applied to laser-microdissected archival specimens. We first improved the bisulfite conversion of genomic DNA in order to analyse cells isolated from archival tissue sections by laser-assisted microdissection. Analysing the methylation of key regulatory genes in archival specimens (n = 38) we could demonstrate that aberrant promoter hypermethylation is an early event during breast cancer development and changes quantitatively and in a gene-specific manner during progression. This novel methodological approach allows the morphology-guided quantitative analysis of changes in the methylation pattern during the clonal evolution of tumour cells. Quantitative differences detected by this assay will offer new insights into early steps in carcinogenesis and tumour cell heterogeneity.

DNA Methylation↗

PubMed1988

Quantitative analysis of the tomographic thallium-201 myocardial bullseye display: critical role of correcting for patient motion.

Single photon emission computed tomography (SPECT) myocardial 201TI imaging appears to offer major improvements over planar imaging. Quantitative analysis of the 201TI images appears to offer major advantages over subjective analysis in planar imaging, but the three-dimensional data available in SPECT images requires special approaches to analysis and display. Thus the myocardial "bullseye" display was developed to summarize and analyze the three-dimensional images of the left ventricle in two dimensions. The relative 201TI distribution to each region of the left ventricle of an individual patient can be displayed as the number of s.d.s away from normal that the region falls. We found that patient motion during the 22 min required for SPECT imaging appeared to produce artifactual defects. Thus, computer programs were developed to quantitate motion between consecutive frames of a [201TI] SPECT myocardial imaging study, simulate nonreturning vertical motion in normal patients, and correct the acquired data for motion. Motion as small as 0.5-1.0 pixel (3-6 mm) in the vertical (axial) direction caused artifactual defects in the quantitative bullseye display that resulted in a false-positive rate of up to 40% for a +1.0 pixel shift. Patient motion of magnitude greater than the threshold value for artifact-production (0.5 pixel) occurred at a rate of 10%, and should be corrected before tomographic reconstruction.

Heart↗

PubMed1996

Quantitative analysis of geometric-pattern features of interstitial infiltrates in digital chest radiographs: preliminary results.

We are developing a computerized method for detection and characterization of interstitial diseases based on a quantitative analysis of geometric features of various infiltrate patterns in digital chest radiographs. In our approach, regions of interest (ROIs) with 128 x 128 matrix size (22.4 mm x 22.4 mm) are automatically selected, covering peripheral lung regions. Next, nodular and linear opacities, which are the basic components of interstitial infiltrates, are identified from two processed images obtained by use of a multiple-level thresholding technique and a line enhancement filter, respectively. Finally, the total area of nodular opacities and the total length of linear opacities in each ROI are determined as measures of geometric pattern features. We have applied this computer analysis to 72 ROIs with normal and abnormal patterns that were classified in advance by six chest radiologists. Preliminary results indicate that the distribution of measures of geometric-pattern features correlate well with radiologists' classification. These early results are encouraging, and further evaluation hopes to establish that this computerized method might prove useful to radiologists in their assessment of interstitial diseases.

Humans↗

PubMed1988

Thermal desorption-capillary gas chromatography for the quantitative analysis of dimethyl sulphate, diethyl sulphate and ethylene oxide in the workplace.

Sampling on solid adsorbents followed by thermal desorption and gas chromatography was evaluated as a simple method for the quantitative analysis of dimethyl sulphate, diethyl sulphate and ethylene oxide in the workplace environment. Tenax TA and Carbosieve S-III (for ethylene oxide) were found to be suitable adsorbents. The charged tubes can be stored at 22 degrees C for 4 days. The recovery is better than 98% (greater than 80% for ethylene oxide) in the mass range 1 ng-1 micrograms. The recovery is not dependent on air humidity. The limits of detection tested were at the lower parts per billion level.

Air Pollutants, Occupational↗

PubMed2006

Quantitative analysis of the ankle strategy under translational platform disturbance.

The ankle strategy is one of the postural adjustment maneuvers humans utilize when the support platform is disturbed. This paper presents a quantitative analysis of the ankle strategy. A three-link sagittal biped model is considered. The first link represents the two legs locked together. The second link represents the two thighs locked together. The third link represents the hip, the torso, the upper limbs, the neck, and the head. The dynamics, control, and stability of the three-link biped, under platform translation, are considered. The disturbance of the platform is represented as an input and the effect of the muscular system is reduced to a set of torques applied to the joints and across the joints. Two digital computer simulations are presented to demonstrate the behavior of the biped under backward or forward platform disturbance. The simulations are compared with experimental measurements of humans subjected to postural disturbances. It is shown that the effect of a horizontal disturbance at the ankle appears to be about 40 times that of the effect of the disturbance at the knees and at least a few hundred times larger than the effect of a disturbance at the hip. This means that, under translational platform disturbance, the ankle angle is subjected to the largest excursion. The knee and the hip angle excursions are relatively minor. Consequently, the biped, as a whole, appears to move as a single inverted pendulum. Major postural corrections are initiated by the ankle excursion. Further, when the available ankle torque is limited or nonexistent, the stability requires resorting to the knee or hip strategies.

Ankle Joint↗

PubMed1981

Regulation of brain cyclic nucleotide phosphodiesterase by calmodulin. A quantitative analysis.

Comparison of the parameters of Ca and Sr binding to bovine brain calmodulin with the activation of bovine brain phosphodiesterase by Ca2+ and Sr2+ at different calmodulin concentrations allows a quantitative description of the mechanism of activation of the enzyme. Equilibrium dialysis studies show that calmodulin possesses three high affinity (K'diss = 6 micoM) and one low affinity (K'diss = 200 microM) sites for Ca2+. All four sites display the same affinity for Sr2+ with K'diss = 180 microM. In the presence of calmodulin, soluble bovine brain phosphodiesterase is activated by Sr2+ to the same extent as by Ca2+. The activation of the enzyme shows the same Ca2+/Sr2+ selectivity ratio of 30 as the binding of the metal ions to calmodulin. Based on the findings that the Ca2+ or Sr2+ concentration at half-maximal activation of the enzyme depends on the concentration of calmodulin present, a quantitative analysis of activation was carried out as a function of the four calmodulin-metal complex species (CaM . Men). The data show that the activating species are CaM . Ca3, CaM . Ca4 or CaM . Sr3, CaM . Sr4. The interaction of these activating species with phosphodiesterase follows the Hill equation with a dissociation constant of 10(-9) M and a Hill coefficient of 2, irrespective of the binding characteristics of Ca2+ or Sr2+. The latter value agrees well with the fact that phosphodiesterase possesses two binding sites for calmodulin.

3',5'-Cyclic-AMP Phosphodiesterases↗

PubMed1993

Quantitative analysis of the human alpha-skeletal actin gene in transgenic mice.

Three aspects of the regulation of the human alpha-skeletal actin gene are examined in this study by quantitative analysis of transgenic tissues: level of expression, tissue specificity, and developmental regulation. Previous in vitro and in vivo studies analyzing the 5' end of the gene have indicated that regulation of tissue-specific expression is promoter based. Transgenic mice were produced carrying either a 9.5-kilobase pair (kb) human alpha-skeletal actin gene fragment or a deletion construct with 2.2-kb of 5' sequences of human alpha-skeletal actin linked to the chloramphenicol acetyltransferase reporter gene. We found that the 9.5-kb transgene was capable of expression in adult skeletal muscle at a level equivalent to that of the endogenous gene in a non-transgenic mouse. The deletion construct was also capable of high-level expression. Both transgenes were expressed in a striated muscle-specific manner and were correctly regulated during development. We conclude that these three parameters of regulation of the human alpha-skeletal actin gene are mediated by sequences within the region -2000 to +239 of the promoter.

Actins↗

PubMed1997

Quantitative analysis of apoptosis and bcl-2 in Sjögren's syndrome.

OBJECTIVE: To determine whether apoptosis plays a significant role in tissue damage of Sjögren's syndrome (SS). METHODS: We performed a quantitative analysis of programmed cell death on salivary glands of 11 patients. Ten age matched women with sicca syndrome served as controls. Morphometric measurement of the fractional volume of acini and ducts showing DNA strand breaks was performed in sections stained by deoxynucleotidyl transferase assay. The extent of bcl-2 expression was determined in sections labeled with monoclonal antibody. The different cell populations infiltrating the glands were examined in tissues stained with anti-leukocyte common antigen and OPD4 monoclonal antibodies. RESULTS: In patients with SS, 68% of the ductal epithelium was occupied by apoptotic structures, whereas only 12% of acini showed DNA strand breaks. Corresponding values in control salivary glands were 3 and 0.13%. bcl-2 labeling was higher in ducts than in acini of both control and pathologic glands. However, in SS a 43% (p < 0.001) and 75% (p < 0.001) reduction in bcl-2 expression was observed in ductal and acinar epithelium, respectively. In comparison with controls, the numerical density of CD4+ cells and plasma cells scattered throughout the interstitium was 323% and 203% higher (p < 0.001) in SS. Moreover, T helper/inducer lymphocytes represented 52% of the inflammatory foci. CONCLUSION: Apoptosis occurs in minor salivary glands of patients with SS with a prevailing localization on the ductal epithelium in association with downregulation of bcl-2 and a large number of infiltrating CD4+ lymphocytes. Thus, the destruction of glandular tissue and the loss of secretory function in SS is dependent on the activation of the suicide program of epithelial cells.

Aged↗

PubMed2001

Quantitative analysis of end-tidal carbon dioxide during mechanical and spontaneous ventilation in infants and young children.

Capnography provides a substitute for monitoring of arterial carbon dioxide tension (PCO(2)). We performed a prospective study to evaluate a new application of capnography, using quantitative curve analysis in the pediatric ICU. Twenty-five infants and children admitted to the pediatric ICU after cardiovascular surgery for congenital heart diseases were included in the study. Capnographic curves were recorded during 3 phases of mechanical and spontaneous ventilation: phase 1, immediate postoperative period; phase 3, preextubation period; and phase 2, period between phases 1 and 3. Each recording included 17 sec of capnographic tracings from consecutive spontaneous and/or ventilator-driven breaths. Quantitative curve analysis was made to define parameters including peak value of exhaled PCO(2) (P), mean rate of rise of PCO(2) (R), and area under each capnographic curve (A). Qualitative inspection of the wave contour showed no obvious difference in phase 3 during spontaneous and mechanically assisted ventilator breaths. However, an obvious difference existed between spontaneous and mechanically assisted breaths in phase 2. For each parameter (P, R, and A), there was a significant difference in phases 2 and 3 from spontaneous breaths. However, there was no significant difference in phases 2 and 3 from ventilator-assisted breaths. We further calculated the ratio of parameters of spontaneous breaths (S) and ventilator-assisted breaths (V) in phase 2 and phase 3. The ratio of S/V for P, R, and A showed significant differences between phase 2 and phase 3. We conclude that quantitative analysis of exhaled end-tidal PCO(2) curves revealed significant changes of specific parameters during the transition from the ventilator-dependent state to the spontaneously breathing ventilator-independent state. This new approach provides a new way to estimate respiratory status in infants and children receiving ventilator therapy. Through quantitative capnographic curve analysis, if P, R, and A from spontaneous breaths approached those of ventilator-assisted breaths, patients have resumed reasonable pulmonary mechanics, and extubation may then be considered.

Capnography↗

PubMed1990

Quantitative analysis of hepatocellular lesions induced by di(2-ethylhexyl)phthalate in F-344 rats.

Di(2-ethylhexyl)phthalate (DEHP), a peroxisome proliferator, has been shown to be a weak hepatocarcinogen in rats and mice. However, in previous studies no quantitative analysis of tumors was carried out. In the present study, F-344 male rats were given a diet containing 2% DEHP ad libitum for 108 wk. At necropsy livers were quantitatively analyzed for total tumor incidence and the number of lesions per liver after slicing the entire organ at 1- to 2-mm intervals. Neoplastic nodules and/or hepatocellular carcinomas were observed in 11 of 14 rats (78.5%). When evaluated according to the size, 57, 16, and 36% rats contained nodules ranging from 1 to 3, 3 to 5, and greater than 5 mm in size, respectively. The number of nodules per liver ranged from zero to four. These results indicate that DEHP induces tumors in a large number of animals at 2% dose levels. It is clear from this study that when a weak peroxisome proliferator is evaluated for carcinogenic effects, a complete and thorough gross examination of the liver is essential to obtain accurate tumor incidence.

Animals↗

PubMed2005

Quantitative analysis of patient-specific dosimetric IMRT verification.

Patient-specific dosimetric verification methods for IMRT treatments are variable, time-consuming and frequently qualitative, preventing evidence-based reduction in the amount of verification performed. This paper addresses some of these issues by applying a quantitative analysis parameter to the dosimetric verification procedure. Film measurements in different planes were acquired for a series of ten IMRT prostate patients, analysed using the quantitative parameter, and compared to determine the most suitable verification plane. Film and ion chamber verification results for 61 patients were analysed to determine long-term accuracy, reproducibility and stability of the planning and delivery system. The reproducibility of the measurement and analysis system was also studied. The results show that verification results are strongly dependent on the plane chosen, with the coronal plane particularly insensitive to delivery error. Unexpectedly, no correlation could be found between the levels of error in different verification planes. Longer term verification results showed consistent patterns which suggest that the amount of patient-specific verification can be safely reduced, provided proper caution is exercised: an evidence-based model for such reduction is proposed. It is concluded that dose/distance to agreement (e.g., 3%/3 mm) should be used as a criterion of acceptability. Quantitative parameters calculated for a given criterion of acceptability should be adopted in conjunction with displays that show where discrepancies occur. Planning and delivery systems which cannot meet the required standards of accuracy, reproducibility and stability to reduce verification will not be accepted by the radiotherapy community.

Film Dosimetry↗

PubMed2006

Quantitative analysis of growth factor production in the mechanism of fibrosis in agnogenic myeloid metaplasia.

OBJECTIVE: The current study quantified the growth factors in megakaryocytes and monocytes and correlated them to the degree of fibrosis, as there is no quantitative analysis of growth factors from megakaryocytes or monocytes reported in patients with agnogenic myeloid metaplasia (AMM). MATERIALS AND METHODS: Megakaryocytes were obtained from cultured blood CD34+ cells. CD14+ cells were sorted by magnetic cell sorting. Quantitative analyses of the growth factors were obtained by real-time reverse-transcriptase polymerase chain reaction techniques and enzyme-linked immunobsorbent assay (ELISA). RESULTS: 1) We found that mRNA levels of transforming growth factor (TGF) beta1, platelet-derived growth factor (PDGF), and fibroblast growth factor (FGF) produced by the megakaryocytes were significantly elevated in AMM compared with those in normal controls (p < 0.05). Although these growth factors were elevated severalfold in AMM compared with other myeloproliferative disorders (MPDs) including essential thrombocythemia and polycythemia vera, they were not statistically significant. 2) TGF-beta1 was more abundantly produced than PDGF or FGF. 3) The mRNA levels of these growth factors produced from CD14+ cells were not significantly elevated in AMM compared with other MPDs or controls; the AMM mRNA levels were significantly elevated only in some patients. 4) The correlation of mRNA levels of these growth factors with the degree of myelofibrosis in AMM was significant with megakaryocytes (r = 0.73) but not with monocytes (r = 0.23). 5) ELISA of the growth factors from the cultured megakaryocytes showed that in most of the patients with AMM and other MPDs, and in volunteer controls, the growth factors were undetectable, and only a few patients with AMM (three each of TGF-beta1 and PDGF and one of FGF) and other MPDs (two of TGF-beta1 and one each of PDGF and FGF) had significantly elevated protein levels of these growth factors. CONCLUSIONS: 1) In AMM, the mRNA levels of these fibrosing growth factors are significantly elevated in megakaryocytes, and they were only elevated in a few patients in the monocyte-macrophage lineages. 2) mRNA of TGF-beta1 is more abundantly produced than that of PDGF or FGF from megakaryocytes. 3) A statistically significant correlation between the growth factor mRNA levels with the degree of myelofibrosis in AMM suggests that these fibrosing growth factors produced by the megakaryocytes may be associated with the etiology of bone marrow fibrosis in AMM. 4) Failure to substantiate at the protein level that megakaryocytes are the main source of growth factors production suggests that other factors or cells initiating translation of the growth factors in the megakaryocytes may also be important in the process of bone marrow fibrosis in AMM. Further studies are necessary.

Cells, Cultured↗

PubMed2004

Quantitative analysis of D-24851, a novel anticancer agent, in human plasma and urine by liquid chromatography coupled with tandem mass spectrometry.

The development of a liquid chromatography/tandem mass spectrometric assay for the quantitative analysis of the novel tubulin inhibitor D-24851 in human plasma and urine is described. D-24851 and the deuterated internal standard were extracted from 250 microL of plasma or urine using hexane/ether (1:1, v/v). Subsequently, 10-microL aliquots of reconstituted extracts were injected onto an Inertsil ODS analytical column (50 x 2.0 mm i.d., 5 microm particle size). An eluent consisting of methanol/5 mM ammonium acetate, 0.004% formic acid in water (80:20, v/v) was pumped at a flow rate of 0.2 mL/min. An API 365 triple quadrupole mass spectrometer was used in the multiple reaction monitoring mode for sensitive detection. For human plasma a dynamic range of 1-1000 ng/mL was validated, and for human urine a range of 0.25-50 ng/mL. Validation was performed according to the most recent FDA guidelines and all results were within requirements. The assay has been successfully applied to support a phase I clinical trial with orally administered D-24851.

Acetamides↗