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At least 1,207 records · Page 67Linked to original sources
PubMed1994

Antibody-mediated complement activation on nucleated cells. A quantitative analysis of the individual reaction steps.

The sequential molecular events of the initiation, amplification, and membrane attack phases of classical C pathway activation on nucleated cells were investigated. As a model system, C-susceptible human melanoma cells (SK-MEL-93-2) expressing the disialoganglioside Ag GD3 were studied. Activation of the classical C pathway was initiated by the anti-GD3 mAb R24 (murine IgG3). The initiation phase is characterized by a very inefficient molar ratio of deposited C1q per Ab molecule. At an Ab density of 5.86 x 10(6) molecules/cell, only 3% of cell-bound R24 molecules form suitable pairs for C1q binding. During the amplification phase maximally 2.44 x 10(6) molecules of C4 and 0.67 x 10(6) molecules of C2/cell are being bound to form the C3 convertase. Despite the rather inefficient binding of C2, the C3 convertase is highly active in depositing high numbers of C3b molecules on the cell surface. Maximum binding of C3b occurred within 5 min of incubation with a total number of 2.1 x 10(7) molecules/cell. This indicates amplification factors at the level of C4 and C3 of 28 (C4/C1q) and 241 (C3/C1q), respectively. C3b was found to be rapidly cleaved into iC3b. As a result of this rapid C3b degradation, the membrane attack phase is initiated with a relatively inefficient C5 activation. The maximal number of 9.5 x 10(5) molecules C5b/cell corresponds to a molar ratio of C5:C3 of only 1:22. The deposition of C5b led to the subsequent maximum binding of the following numbers of molecules of terminal C components per cell: C6, 0.8 x 10(6); C7, 0.89 x 10(6); C8, 0.82 x 10(6); C9, 1.8 x 10(6). These numbers correspond to average molar ratios (calculated per C5b molecule) of C5b/C6/C7/C8/C9 of 1/0.85/0.94/0.86/1.88. In addition to the monomeric C9, dimeric and polymeric (12- to 16-mer) forms of the molecule could be demonstrated. Collectively, our data represent a first comprehensive quantitative analysis of classical pathway activation on a nucleated cell.

Antibodies, Monoclonal↗
PubMed2003

Quantitative analysis of osteoblast behavior on microgrooved hydroxyapatite and titanium substrata.

The effects of implant surface topography and chemistry on osteoblast behavior have been a research focus because of their potential importance in orthopedic and dental applications. This work focused on the topographic effects of hydroxyapatite (HA) and titanium (Ti) surface that had identical micropatterns to determine whether there was synergistic interaction between surface chemistry and surface topography. Surface microgrooves with six different groove widths (4, 8, 16, 24, 30, and 38 microm) and three different groove depths (2, 4, and 10 microm) were made on single crystalline silicon wafers using microfabrication techniques. Ti and HA thin films were coated on the microgrooves by radio-frequency magnetron sputtering. After that, human osteoblast-like cells were seeded and cultured on the microgrooved surfaces for up to 7 days. The cells' behavior was examined using scanning electron microscopy after cells were fixed and dehydrated. Statistical analysis was based on quantitative data of orientation angle, evaluating the contact guidance, and form index, describing cell shape or cell morphology changes. The contact guidance and cell shape changes were observed on the HA and Ti microgrooves. No difference in orientation angle between HA and Ti microgrooves was found. This might suggest that surface chemistry was not a significant influence on cell guidance. However, the form index analysis indicated an interaction between topographic effects and surface chemistry. Thus, conclusions about surface topographic effects on cell behavior drawn from one type of material cannot simply be applied to another type of material.

Durapatite↗
PubMed2006

Three-dimensional (3D) reconstruction and quantitative analysis of the microvasculature in medulloblastoma and ependymoma subtypes.

In the World Health Organisation (WHO) classification of tumours of the nervous system, four main histopathological subtypes of medulloblastomas (classic medulloblastoma, desmoplastic medulloblastoma, medulloblastoma with extensive nodularity and advanced neuronal differentiation and large cell/anaplastic medulloblastoma) as well as of ependymal tumours (low-grade ependymoma, anaplastic ependymoma, myxopapillary ependymoma and subependymoma) are recognised. Under the hypothesis that the microvascular architecture of tumours is a reflection of the histopathological subtype, we performed three-dimensional reconstructions of the microvasculature in these subtypes of medulloblastomas and ependymal tumours using computerised image analysis. In addition, we quantitatively assessed three microvascular parameters (number, area, perimeter) in these neoplasms. Three-dimensional reconstructions showed a dense pattern of irregular vessels in classic and large cell medulloblastoma. In desmoplastic medulloblastoma and medulloblastoma with extensive nodularity, the vessels were more unevenly distributed and organised around the nodular areas. Classic medulloblastoma and large cell medulloblastoma had on average the largest vessel area and perimeter. The highest number of vessels was seen in classic medulloblastoma and medulloblastoma with extensive nodularity. Three-dimensional analysis of ependymal tumours showed that low-grade ependymoma had larger but fewer vessels compared to anaplastic ependymoma, while myxopapillary ependymoma had a complex, heterogeneous pattern of vessels and subependymoma few but regular vessels. In ependymal tumours, the highest values for vessel number, vessel area and vessel perimeter were found in anaplastic ependymoma and the lowest values in subependymoma. We conclude that our three-dimensional reconstructions shed unprecedented light on the tumour vasculature in medulloblastomas and ependymal tumours and expect that such reconstructions are helpful tools for further studies on tumour angiogenesis.

Adult↗
PubMed1995

Quantitative analysis of the tomographic technetium-99m MIBI (99mTc-MIBI) myocardial bullseye display: application to diagnosis of coronary artery disease.

In this study, the 99mTc-MIBI myocardial bullseye display of 31 healthy persons and 34 patients with myocardial ischemia and 17 patients with myocardial infarction were analyzed quantitatively; and compared with the results of myocardial tomography analysis and qualitative bullseye analysis. The sensitivities of the three methods were 88.2%, 91.2% and 94.1% respectively (P > 0.05), and the specificities were 93.5%, 83.9% and 83.9% respectively (P < 0.05). On the other hand, the quantitative analysis obviously outperformed the other two methods in the detection of ischemic segments of myocardium near infarction zone (P < 0.01). The quantitative analysis of 99mTc-MIBI myocardial bullseye (quantitative bullseye) was an objective, specific and sensitive method for diagnosis of coronary artery disease.

Adult↗
PubMed2004

Selenium and lung cancer: a quantitative analysis of heterogeneity in the current epidemiological literature.

While numerous laboratory investigations have shown that selenium may have anticarcinogenic activity, the epidemiological data have been inconsistent. In this report, meta-analysis was used to quantitatively summarize the existing epidemiological evidence on selenium and lung cancer and identify sources of heterogeneity among studies. When all studies were combined, the summary relative risk (RR) for subjects with higher selenium exposures was 0.74 [95% confidence interval (CI) 0.57-0.97]. In subgroup analyses based on the average selenium level in the study population, the summary RR for areas where selenium levels were low was 0.72 (95% CI 0.45-1.16), while the RR for areas where selenium levels were higher was 0.86 (95% CI 0.61-1.22). In both studies in high selenium areas where RRs were markedly below 1.0, protective effects were only found when subjects in the lowest category of selenium exposure were used as referents. No clear protective effects were seen when highly exposed subjects were compared with those in the middle exposure categories. The summary RR was lower in studies assessing selenium exposure using toenails (RR 0.46, 95% CI 0.24-0.87) than in studies using serum selenium (RR 0.80, 95% CI 0.58-1.10) or studies assessing dietary intake (RR 1.00, 95% CI 0.77-1.30). Overall, these results suggest that selenium may have some protective effect against lung cancer in populations where average selenium levels are low. The evidence for these findings is greater in studies of toenail selenium than in studies involving other measures of exposure.

Biomarkers, Tumor↗
PubMed1998

Quantitative analysis on the localization of chondroitin sulfate proteoglycan in renal tissues of patients with calcium nephrolithiasis.

Previous studies have shown a significant decrease of heparin sulfate proteoglycan (HSPG) in the basement membrane of the glomerulus and the mucosa of the ureter/renal pelvis in patients with calcium nephrolithiasis. In this study, we looked at the localization of another influential proteoglycan, chondroitin sulfate (CSPG), using similar study groups by indirect immunofluorescence staining. Microscopic images were digitized and image analysis was used to quantitate the staining intensity of CSPG present in the basement membrane of the nephron. Our data showed significant loss of CSPG in the Bowman's capsule and the basement membrane of the mucosa of the ureter/renal pelvis using Mann-Whitney U-Wilcoxon Rank Sum W test with P-values of 0.0043 and 0.0041, respectively. However, absence of staining was noted in the basement membrane of the glomerulus and no significant change in the basement membrane of the tubular epithelium was observed. In conclusion, our results showed changes in the localization of CSPG in the basement membrane of the nephron, accompanied with HSPG, which may contribute to the pathological condition of calcium nephrolithiasis.

Adult↗
PubMed1995

Healthy human T-cell receptor beta-chain repertoire. Quantitative analysis and evidence for J beta-related effects on CDR3 structure and diversity.

Analysis of TCR repertoire usage and clonality is of potential value in understanding the pathogenesis of a number of human immune-mediated diseases. In diseases that are likely to be dependent on antigen-driven T cells, it has been suggested that particular TCR junctional region or CDR3 sequences may be critical. Rigorous methods for TCR analysis which are both quantitative and qualitative are therefore required. Of those commonly available, only anchor and inverse PCR are capable of giving high-quality information on V, D, N, and J region usage, but it has not been established whether both methods are quantitatively or analytically equivalent. We show here that both methods detected considerable variability in the usage of V beta and J beta segments in the peripheral blood repertoire of a normal individual. No preferential V-J pairing could be demonstrated. An excess usage of J beta 2 family members was indicated by both methods, although the relative usage of different J beta 2 families differed between the two techniques. The predominantly used V beta usage showed that for some families, estimates of their frequency in the repertoire differed significantly between the anchor and inverse libraries. When sampling relatively few clones the variation between V beta families estimated using the two methods can be considerable. This is likely to be a result of sampling error from a large gene family. Large-scale screening of several thousand clones is recommended to confirm the absolute values obtained from sequencing. Variation in CDR3 length appeared to be normally distributed, suggesting that a statistically optimal junctional region length may have been selected for contact with antigen. CDR3 length distribution differs significantly between receptors, which have rearranged to J beta 1 versus J beta 2 families, with the J beta 2-associated CDR3 on average between 0.5 and 1.2 of an amino acid longer. Thus the TCR beta junctional region repertoire of humans is subject to structural constraints associated with J beta usage. It will be important to establish whether variation in CDR3 length and J beta usage exists between subsets of human T cells in order to interpret TCR repertoire data from disease and control tissues.

Adult↗
PubMed1999

Quantitative analysis of masseter and temporalis EMGs: a comparison of anterior guided versus balanced occlusal concepts in patients wearing complete dentures.

The lack of easily measurable, objective physiological activity parameters of the masseter and temporalis muscle during jaw movements in humans has led to the consideration to revise data of surface electromyographies (EMGs) by applying a computerized quantification method. The aim of this follow-up analysis was to get quantitative data out of EMG-records of an earlier study. These records were obtained with two different splints, splint 1 providing an anterior front-canine guidance and splint 2 providing bilateral balanced occlusion. Utilizing a computer aided integration method led to numeric results which statistically proves the prediction of the previous investigation. Applying the integration method, the EMG raw signal was transformed into area-values which enabled a statistical work up of the data. Wilcoxon test statistics shows a significant (P<0.05) lower muscle activity in patients wearing dentures providing anterior front-canine guidance compared to those with balanced occlusion. It is concluded that the neuromuscular activity of the elevator muscles is highly reproducible and that the neuromuscular function is similar in edentulous subjects to that found in people with natural teeth. Furthermore, the study statistically proves earlier visual data that all those subjects, whose muscle activities were observed with anterior guidance (splint 1) compared to bilateral balanced occlusion (splint 2) showed significantly lower values with regard to subjects wearing splint 2.

Centric Relation↗
PubMed1993

Quantitative analysis of the human immunodeficiency virus type 1 (HIV-1)-specific cytotoxic T lymphocyte (CTL) response at different stages of HIV-1 infection: differential CTL responses to HIV-1 and Epstein-Barr virus in late disease.

Major histocompatibility complex (MHC)-restricted cytotoxic T lymphocytes (CTL) are part of the cellular immune response to human persistent virus infections. Measurements of the frequency and specificity of human immunodeficiency virus type 1 (HIV-1)-specific CTL and their variation with time may indicate their relative importance in modulating the progression of HIV-1 infection. We have used limiting dilution analysis (LDA) to derive quantitative estimates of the frequency of HIV-1-specific CTL precursors in a cross-sectional study of 23 patients at different clinical stages of HIV-1 infection and to compare these with the frequency of CTL precursors specific for another persistent virus (Epstein-Barr virus [EBV]) in the same patients. Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with autologous HIV-1-infected lymphoblasts and assayed for cytotoxicity in 51Cr release assays against autologous and MHC-mismatched lymphoblastoid B cells infected with recombinant vaccinia viruses expressing the three HIV-1 structural gene products. The frequency of MHC-restricted precursors was high in asymptomatic HIV-1-infected patients (env-specific CTL precursors up to 73/10(6) PBMC; gag-specific CTL precursors up to 488/10(6) PBMC), although the relative frequency against the different structural gene products varied from patient to patient. The HIV-1-specific CTL precursor frequency was reduced in patients who had more severe (< 400/microliters) CD4+ lymphocyte depletion, while in the majority of such patients the frequency of CTL precursors against EBV was maintained at levels observed in healthy controls. Direct CTL activity in unstimulated PBMC was observed in three of nine patients but no correlation was found between the presence of an activated CTL response and the magnitude of the CTL response detected after stimulation in LDA. Thus, CTL precursors were detected against all three HIV-1 structural gene products in patients with CD4+ lymphocyte counts > 400/microliters, at frequencies that are high compared with those reported for other persistent viruses. A CTL response directed against multiple protein antigens of HIV-1 may protect the patient against epitope variation. The fact that the EBV-specific CTL precursor frequencies were maintained in advanced HIV-1 infection suggests that there may be selective impairment of the HIV-1-specific CTL response associated with disease progression.

Adult↗
PubMed1995

Quantitative analysis of the transcriptional start sites of estrogen receptor in breast carcinoma.

Recent studies have identified an estrogen receptor (ER) promoter upstream of the transcriptional start site originally mapped for the ER gene. We have examined promoter use in a number of breast carcinoma cell lines. MCF7, T47D, BT474, and MDA-MB-361 cell lines all use the P0 promoter, whereas BT20 and ZR75-1 do not demonstrate transcription from this upstream start site. S1 nuclease analysis was used to quantitate the amount of ER mRNA originating from the two different promoters. In MCF7, one-third of the ER mRNA results from transcription originating upstream of the major ER promoter and in T47D, 12% of the message originates from upstream transcription. Promoter use was analyzed in human mammary epithelial cells and human late proliferation endometrium. Upstream promoter use was found to be characteristic of human late proliferation endometrium but not human mammary epithelial cells. These results indicated that certain breast carcinomas demonstrate ER transcription from a promoter not normally active in normal breast epithelium. This activation may involve a factor active in normal human endometrium.

Base Sequence↗
PubMedDate not supplied

Quantitative analysis of 2-aminoacetophenone in off-flavored wines by stable isotope dilution assay.

Isotope dilution analysis was used to quantitate 2-aminoacetophenone in wines exhibiting the so-called untypical aging off-flavor. d3-Aminoacetophenone was synthesized and used as isotopomeric internal standard. The method of quantitation was verified by several model experiments. In the off-flavored wines studied, amounts of 2-aminoacetophenone ranging from 0.7 to 12.8 micrograms/L were determined.

Acetophenones↗
PubMed2004

Quantitative analysis of diffusion tensor orientation: theoretical framework.

Diffusion-tensor MRI (DT-MRI) yields information about the magnitude, anisotropy, and orientation of water diffusion of brain tissues. Although white matter tractography and eigenvector color maps provide visually appealing displays of white matter tract organization, they do not easily lend themselves to quantitative and statistical analysis. In this study, a set of visual and quantitative tools for the investigation of tensor orientations in the human brain was developed. Visual tools included rose diagrams, which are spherical coordinate histograms of the major eigenvector directions, and 3D scatterplots of the major eigenvector angles. A scatter matrix of major eigenvector directions was used to describe the distribution of major eigenvectors in a defined anatomic region. A measure of eigenvector dispersion was developed to describe the degree of eigenvector coherence in the selected region. These tools were used to evaluate directional organization and the interhemispheric symmetry of DT-MRI data in five healthy human brains and two patients with infiltrative diseases of the white matter tracts. In normal anatomical white matter tracts, a high degree of directional coherence and interhemispheric symmetry was observed. The infiltrative diseases appeared to alter the eigenvector properties of affected white matter tracts, showing decreased eigenvector coherence and interhemispheric symmetry. This novel approach distills the rich, 3D information available from the diffusion tensor into a form that lends itself to quantitative analysis and statistical hypothesis testing.

Adolescent↗
PubMed2000

Quantitative analysis of proinflammatory cytokines (IL-1beta, IL-6, TNF-alpha) in human skin wounds.

Proinflammatory cytokines play an important role in the mediation of inflammation and trauma. They could be useful for the determination of vitality and wound age. In the present study, 144 human skin wounds due to sharp force were investigated. The material was collected during operations (N=96) and postmortem examinations (N=48). The wound age varied from several seconds or minutes to 9 days. Control skin was available in each individual. The tissue specimens were homogenized and extracted in a solution of PBS and protease inhibitors. Interleukin-1beta (IL-1beta), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) were measured by quantitative ELISA analysis. Statistical evaluation was performed by the t-test using the quotients of levels (wound sample/control skin). In surgical specimens the cytokine levels revealed a clear tendency to increase with wound age. IL-1beta in early skin wounds (</=30 min) and TNF-alpha after a wound age of 1-2 h demonstrated statistically significant changes in comparison with control skin (P<0.05). In autopsy samples with severe traumatization excessive elevation of cytokine levels was observed: IL-1beta, IL-6 and TNF-alpha showed significant increases (P<0.001-0.05) in stab and incised wounds with very short survival times of less than 5 min, but not in possibly supravital injuries. Elevated IL-6 levels persisted in older wounds (>24 h, P<0.05). The quantitative analysis of proinflammatory cytokines in wound extracts can contribute to the determination of vitality and wound age, in particular in the very early post-traumatic interval (classic stab wounds).

Aged↗
PubMed2003

Temporal bone histopathological and quantitative analysis of mitochondrial DNA in MELAS.

OBJECTIVES/HYPOTHESIS: Although hearing loss is common in MELAS (syndrome of mitochondrial encephalopathy, lactic acidosis and stroke-like episodes), the histopathology of the temporal bone has not been reported. The majority of cases of MELAS are linked to a mitochondrial DNA (mtDNA) mutation at nucleotide 3243. In MELAS, normal mtDNA and mutant mtDNA coexist in a heteroplasmic manner. The purpose of the study was to report the otopathological findings from two patients with MELAS and quantitative mtDNA analysis in the inner ear of one of these patients. STUDY DESIGN: Basic scientific histopathological examination and quantitative mtDNA analysis of the temporal bone. METHODS: Temporal bones were embedded in celloidin and sectioned for light microscopic study. Graphic reconstruction of the cochlea was performed using the method described by Schuknecht. For quantitative mtDNA analysis, total DNA from the membranous part of the inner ear was collected, amplified by polymerase chain reaction, and digested with the restriction enzyme. The percentage of mutant/total mtDNA was measured by the ratio of fluorescence intensity. RESULTS: Histopathological examination revealed severe degeneration of the stria vascularis and degenerative change of spiral ganglion cells in both patients. The quantitative DNA studies showed that the proportion of mutant to wild-type mtDNA was similar in both histologically affected and histologically unaffected tissues within the inner ear. CONCLUSION: Dysfunction of the stria vascularis and spiral ganglion cells causes sensorineural hearing loss in MELAS.

Adult↗
PubMedDate not supplied

Normal magnetic resonance contrast enhancement of extraocular muscles: a quantitative analysis.

The purpose was to evaluate quantitatively the magnetic resonance contrast enhancement of normal extraocular muscles and the use of temporal muscles as a reference of enhancement. Eighty extraocular and 20 temporal muscles were taken into analysis. Before contrast administration, mean intensity of extraocular muscles was found to be higher than that of temporal muscles (p < 0.000). With contrast agent, all extraocular muscles were enhanced more (111% enhancement) than the temporal muscles (45% enhancement, p < 0.000). Lateral recti had the lowest signal intensity, both in pre- and postcontrast images (p < 0.005). Normal extraocular muscles showed prominent enhancement on contrast-enhanced T(1)-weighted images. Temporal muscles were also enhanced in all subjects, urging the observers to compare the enhancement of extraocular muscles not with the latter.

Adolescent↗
PubMed1989

Detection of multivessel disease in patients with sustained myocardial infarction by thallium 201 myocardial scintigraphy: no additional value of quantitative analysis.

This study was performed to determine the value of visual and quantitative thallium 201 scintigraphy for the detection of multivessel disease in 67 patients with a sustained transmural myocardial infarction. Also the viability of the myocardial regions corresponding to pathologic Q-waves was evaluated. Of the 67 patients, 51 patients had multivessel coronary artery disease (76%). The sensitivity of the exercise test was 53%, of thallium scintigraphy 69%, when interpreted visually, and 67%, when analysed quantitatively. The specificity of these methods was 69%, 56%, and 50%, respectively. Sixty-two infarct-related flow regions were detected by visual analysis of the thallium scans, total redistribution was observed in 11/62 (18%) of patients, partial redistribution in 26/62 (42%), and no redistribution in 25/62 (40%) of patients. The infarct-related areas with total redistribution on the thallium scintigrams were more likely to be associated with normal or hypokinetic wall motion (7/11: 64%) than the areas with a persistent defect (7/25:28%) (P = 0.05), which were more related with akinetic or dyskinetic wall motion. Based on our results, it is concluded that 1) both visual and quantitative analysis of thallium exercise scintigraphy have limited value to predict the presence or absence of multivessel coronary artery disease in patients with sustained myocardial infarction, and 2) exercise-induced thallium redistribution may occur within the infarct zone, suggesting the presence of viable but jeopardized myocardium in presumed fibrotic myocardial areas.

Coronary Angiography↗