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PubMed2002

The prognostic value of metalloproteinases and angiogenic factors in ovarian carcinoma.

The objective of this study was to analyze the correlation between matrix metalloproteinases (MMPs) and angiogenic genes and survival in advanced-stage ovarian carcinomas. Primary and metastatic ovarian carcinomas from patients diagnosed with FIGO stage III-IV disease and followed up to 20 years were studied using mRNA in situ hybridization (ISH). Expression of MMP-2, MMP-9, membrane-type 1-MMP (MT1-MMP), the MMP inhibitor TIMP-2, vascular endothelial growth factor (VEGF), interleukin-8 (IL-8) and basic fibroblast growth factor (bFGF) was studied. MMP-2, MMP-9 and TIMP-2 mRNA was detected in both tumor and stromal cells, while MT1-MMP was largely confined to tumor cells. In univariate analysis of primary tumors, TIMP-2 and MMP-9 mRNA expression correlated with poor outcome. In metastatic lesions, mRNA expression of TIMP-2, MMP-2, and MT1-MMP correlated with poor survival. In a multivariate analysis of primary tumors, TIMP-2 expression in stromal cells (P=0.006) and MMP-9 expression in tumor cells (P=0.011) retained their predictive value. Intense expression of bFGF mRNA and weak expression of IL-8 mRNA was detected in both stromal and tumor cells in most cases, while VEGF mRNA expression was limited to a few cases. Angiogenic mRNA expression showed no correlation with disease outcome in survival analysis (P>0.05). We conclude that bFGF is the major angiogenic factor expressed in ovarian carcinoma at the mRNA level. MMP-2, MMP-9, MT1-MMP and TIMP-2 are valid markers of poor survival in advanced-stage ovarian carcinoma.

Adult↗

PubMed2004

[Migration and invasion of human hepatocellular carcinoma mediated by lung extracts].

BACKGROUND & OBJECTIVE: Invasion and metastasis are obstacles to successful treatment of hepatocellular carcinoma. Lung is the most common site of distant metastasis from hepatocellular carcinoma. In in vitro chemoinvasion assay that different tissue extracts from mice were used to induce human hepatocellular carcinoma cells with different metastatic potentials, lung extracts show the strongest inducing activity. This study was designed to investigate the mechanism of migration and invasion in human hepatocellular carcinoma with highly metastatic potential mediated by lung extracts from mice. METHODS: The changes of cytoskeleton were tested using F-actin polymerization assay and flow cytometry (FCM). Correlation between matrix metalloproteinas-9 and F-actin was analyzed by fluorescence double staining in human hepatocellular carcinoma MHCC97-H cells induced by lung extracts. RESULTS: When MHCC97-H cells were incubated with serum-free medium or spleen extracts, the cells showed elongated or polygonal morphology. When MHCC97-H cells were incubated with lung extracts, the formation of lamelliopodia or filopodia became more and more obvious and distinct as time increasing. Results of FCM showed that 1.9-fold increase in intracellular F-actin within 30s after MHCC97-H cells were incubated with lung extracts. Confocal laser scan microscopy of MHCC97-H cells stimulated in suspension showed intense F-actin staining in the periphery of the cells and redistribution of F-actin towards a leading edge. MMP-9 and F-actin were mainly localized in the perinuclear pool when the cells were incubated with serum-free medium. After stimulation with lung extracts, MMP-9 and F-actin were localized at the front of extending pseudopodia of MHCC97-H cells. CONCLUSION: The mechanism that lung extracts promote migration and invasion of MHCC97-H may correlate with the pseudopodia formation and reorganization of MMP-9. Lung extracts may contribute to organ-specific metastasis of hepatocellular carcinoma.

Animals↗

PubMed1996

Formation of reversible disulfide bonds with the protein matrix of the endoplasmic reticulum correlates with the retention of unassembled Ig light chains.

Exposed thiols act as intracellular retention elements for unassembled secretory molecules. Yet, some free Ig lambda light chains are secreted despite the presence of an unpaired cysteine (Cys214). This is due largely to the presence of a flanking acidic residue: substitution of Asp213 for Gly or Lys increases pre-Golgi retention and degradation of free lambda. Secretion is restored by exogenous reducing agents or by assembly with heavy chains. In the endoplasmic reticulum (ER), lambda chains form covalent complexes with many proteins through Cys214. These complexes are absent from the Golgi. They are more abundant in transfectants expressing the lambdaGly2I3 and lambdaLys213 mutants that are poorly secreted. Radioactive N-ethylmaleimide labels some monomeric lambda chains isolated from the ER, but not from the Golgi or from the medium, indicating that the Cys214 thiol is masked during ER-Golgi transport. Mass spectrometry reveals the presence of a free cysteine residue disulfide-linked to Cys214. We suggest that thiol-mediated retention involves the formation of reversible disulfide bonds with the protein matrix of the ER. The presence of an acidic residue next to the critical cysteine may allow the masking of the thiol and transport to the Golgi.

Base Sequence↗

PubMed2006

Aortic stiffness correlates with an increased extracellular matrix turnover in patients with dilated cardiomyopathy.

BACKGROUND: An increased extracellular matrix (ECM) turnover has been associated with poor survival in patients with chronic heart failure (CHF) due to dilated cardiomyopathy (DCM). However, the influence of the accelerated collagen turnover on the progressive large artery stiffening process characterizing CHF has not been clarified. This is relevant because aortic stiffening imposes an additional systolic load and impairs exercise tolerance in CHF patients. Therefore, we investigated whether the serum aminoterminal propeptide of type III collagen (PIIINP), an established marker of ECM turnover and tissue fibrosis in DCM, was associated with aortic stiffness in DCM patients. METHODS AND RESULTS: A total of 89 patients with clinical diagnosis of DCM (age 62 +/- 9 years, 80% men, mean ejection fraction 34% +/- 8%) were selected. Aortic pulse-wave velocity (PWV), a well-established marker of aortic stiffness, was measured by Doppler ultrasonography. Serum concentration of PIIINP was determined by radioimmunoassay. Mean aortic PWV was 5.7 +/- 2.3 m/s, and PIIINP was 5.0 +/- 1.3 microg/L. The variables correlated with aortic PWV were age (r = 0.33, P = .002), PIIINP (r = 0.30, P = .005), heart rate (r = 0.27, P = .02), stroke volume (r = -0.24, P = .03) and New York Heart Association class (r = 0.25, P = .02). In a multivariate analysis, age (P = .02) and PIIINP (P = .01) were independently related with aortic PWV, accounting for 27% of its variance. CONCLUSIONS: Higher serum PIIINP levels are independently associated with a stiffer aorta in DCM patients. This suggests that abnormalities in the ECM turnover might involve the proximal elastic vasculature and could partially explain the progressive large artery stiffening process characterizing CHF.

Aged↗

PubMed1989

Mouse L cells expressing human prourokinase-type plasminogen activator: effects on extracellular matrix degradation and invasion.

A cosmid (cos pUK0322) harboring the complete human urokinase-type plasminogen activator (u-PA) gene and Geneticin resistance as a selectable marker was isolated from a human genomic library and characterized. After transfection of cos pUK0322 into mouse L cells and selection, several plasminogen activator (PA)-expressing clones were obtained and one (LuPA) was chosen for additional study. The PA expressed was identical to human pro-u-PA in enzymatic, electrophoretic, and antigenic properties. The expression of PA was stable over 50 population doublings. The regulation of the transfected gene was studied by treatment of the cells with various hormones and other effectors. Expression of PA activity was inhibited fivefold by dexamethasone and stimulated two- to threefold by agonists of the adenylate cyclase dependent pathway of signal transduction, such as dibutyryl cyclic AMP and cholera and pertussis toxins. The modulation of PA activity was associated with corresponding changes in mRNA steady-state levels. The phenotypic changes associated with pro-u-PA expression were analyzed in vitro by degradation of 3H-labeled extracellular matrix (ECM), invasion of a matrigel basement membrane analogue, and by light and electron microscopy. LuPA cells and reference HT-1080 fibrosarcoma cells, in contrast to control Lneo cells transfected with the neomycin resistance gene, degraded the ECM and invaded the matrigel basement membrane. Matrix degradation correlated with the modulation of pro-u-PA gene expression as it was inhibited by dexamethasone and promoted by dibutyryl cyclic AMP. Inhibition of PA or plasmin using anti-u-PA IgG or aprotinin prevented ECM degradation and invasion. These results demonstrate that u-PA expression alone is sufficient to confer to a cell an experimental invasive phenotype.

Animals↗

PubMed2001

Up-regulation of matrix metalloprotease-9 in middle ear cholesteatoma--correlations with growth factor expression in vivo?

The role of matrix metalloproteases and their regulation in the pathology of middle ear cholesteatoma is still unclear. Recently we have demonstrated that incubation of keratinocytes with cholesteatoma debris and granulation tissue extracts causes induction of gelatinase B (matrix metalloproteinase-9, MMP-9) secretion in vitro. Antibodies against a variety of growth factors revealed some inhibitory effect on MMP-9 induction, caused by debris or granulation tissue extracts. In order to investigate the coherence of growth factor expression and matrix metalloproteinase activity in vivo in middle ear cholesteatoma, we performed quantitative gelatin zymographic analysis with tissue homogenates of 37 cholesteatoma and nine external ear canal skin (EACS) samples. Furthermore we quantified levels of the cytokines IL-1alpha, IL-1beta, TNF-alpha, TGF-beta and EGF present in tissue extracts, using enzyme-linked immunosorbent assays (ELISA), and correlated cytokine concentrations with gelatinolytic activities. Zymographic analysis revealed a highly heterogeneous expression of gelatinase A and B in cholesteatoma specimens. As shown previously, MMP-9, but not MMP-2, was increased in cholesteatoma when compared to EACS samples. ELISA studies revealed a significantly elevated IL-1alpha level in cholesteatoma. Regression analysis involving gelatinolytic activity and cytokine concentrations in tissue homogenates showed no statistically significant correlation between expression of gelatinases and the cytokines IL1-alpha, IL1-beta, TNF-alpha, TGF-beta or EGF. The discrepancy between in vitro observations and the situation in vivo is discussed critically.

Cholesteatoma, Middle Ear↗

PubMed2006

Altered cell adhesion and cell viability in a p38alpha mitogen-activated protein kinase-deficient mouse embryonic stem cell line.

p38 mitogen-activated protein (MAP) kinase alpha (p38alpha) is a broadly expressed protein kinase that regulates growth and development. Most studies of p38alpha have been in somatic cells. Little is known about its function in embryonic stem (ES) cells. Using a ES cell line isolated from p38alpha knockout mouse embryos (p38alpha (-/-) ES cells), we investigated roles of p38alpha in the regulation of ES cell activities. p38alpha (-/-) ES cells displayed several altered features different from wild-type cells. The major findings are that p38alpha (-/-) ES cells have significantly increased cell adhesion to several extracelluar matrix proteins, correlating with elevated phosphorylation of focal adhesion kinase and paxillin. p38alpha (-/-) ES cells also showed increased cell viability, correlating with increased expression of survivin and activation of AKT (protein kinase B), two molecules that are known to improve cell viability. p38alpha (-/-) ES cells reach confluence faster than wild-type cells in routine cell culture. However, this is not due to a higher cell proliferation rate in p38alpha (-/-) ES cells, but rather is likely a result of improved cell adhesion and/or cell viability. Together our results indicated that p38alpha may negatively regulate mouse ES cell adhesion and viability.

Animals↗

PubMed1999

Basement membrane material in ovarian clear cell carcinoma: correlation with growth pattern and nuclear grade.

Stromal hyalinization in ovarian clear cell carcinomas has been suggested to be caused by deposition of basement membrane (BM) material, but the biological and diagnostic significance of this finding remains unknown. The distribution of BM material in 17 primary ovarian clear cell carcinomas was examined semiquantitatively using hematoxylin and eosin-stained sections and immunohistochemistry with antibodies to laminin and type IV collagen. For comparison, other surface epithelial tumors, including 8 serous tumors of low malignant potential, 10 serous adenocarcinomas, 6 mucinous tumors of low malignant potential, 5 mucinous adenocarcinomas, 6 endometrioid carcinomas, 4 Brenner tumors, 1 transitional cell carcinoma, and 3 undifferentiated carcinomas, were examined. Stromal hyalinization was found in all 17 clear cell carcinomas and was immunoreactive for type IV collagen and laminin. Other types of surface epithelial tumor lacked these findings. In clear cell carcinoma, areas showing a papillary pattern tended to show abundant deposition regardless of nuclear grade, whereas in solid, tubular, or cystic areas, the deposition was more prominent in areas showing high-nuclear-grade features (grade 2 and 3) than in areas with low-nuclear-grade features (grade 1). Dense deposition of BM material recognized as stromal hyalinization on hematoxylin and eosin-stained sections in primary ovarian clear cell carcinoma is a characteristic feature that is not seen in other ovarian surface epithelial tumors. This matrix production correlates with high-nuclear-grade features and papillary growth pattern.

Adenocarcinoma, Clear Cell↗

PubMed1986

Cross-linking patterns in salt-extractable extensin from carrot cell walls.

Extensins are hydroxyproline-rich glycoproteins (HRGPs) found in the primary cell walls of dicots. Extensin monomers are secreted into the wall and covalently bound to each other, presumably by isodityrosine (IDT) cross-links, to form a rigid matrix. Expression of the extensin matrix is correlated with inhibition of cell elongation during normal development and with increased resistance to virulent pathogens. We have isolated extensin from carrot root tissue (Daucus carota L.) by published techniques and have used gel filtration chromatography to purify fractions enriched in monomers and oligomers. We refer to this protein as "extensin-1" to distinguish it from "extensin-2," a second extensin-like HRGP from carrot which we will describe later. We prepared extensin-1 for electron microscopy by shadowing it with platinum. Monomers are highly elongated ( congruent with84 nanometers) and kinked at several sites. Kinks occur at all sites on molecules with nearly equal probability, but do not appear to occur at their ends. The distribution of kinks is similar to that of tyrosine-lysine-tyrosine sequences, which have been shown to be capable of forming intramolecular IDT cross-links, so we suggest that kinks are visible manifestations of intramolecular IDTs. Oligomers likely result from IDT cross-links between monomers, and may be regarded as transient precursors of the fully cross-linked matrix. Nearly 60% of cross-links involve the ends of molecules while the rest are scattered among internal sites. We discuss how the relative positions and proportions of intra- and intermolecular cross-links in extensin-1 may affect the structure, and in turn the function, of the extensin matrix.

Journal Article↗

PubMed2000

Molecular mechanism of diabetic nephropathy.

Diabetic nephropathy is one of the main causes of renal end-stage disease. Morphologically, the development of diabetic nephropathy is characterized by progressive thickening of the glomerular basement membrane and by expansion of the mesangial matrix which correlates to glomerular filtration function. In vitro studies with cultured mesangial cells revealed that elevated glucose concentrations increase collagen synthesis similar to the in vivo situation. These studies showed that hyperglycemia may be toxic either by non-enzymatic reaction of glucose with proteins and subsequent formation of advanced glucosylation end products or by increased metabolism leading to increased oxidative stress and activation of protein kinase C resulting in increased production of cytokines. Particularly, de novo synthesis of transforming growth factor beta1 (TGF-beta1) is induced and TGF-beta1 appears also involved since blockage of this prosclerotic factor inhibits high glucose-induced collagen synthesis. Interestingly, it could be demonstrated that angiotensin II also stimulates TGF-beta1 production possibly via the same signal transduction pathway. Besides the classical clinical chemical parameters for evaluation of renal function, the measurement of urinary albumin excretion is now widely used for detection of developing diabetic nephropathy. Since diabetes causes glomerular and tubular changes, tubular marker proteins may be used to detect early renal damage. An increased urinary excretion of matrix proteins (e.g. collagen) and cytokines (e.g. TGF-beta1) was found in early diabetic nephropathy. However, the diagnostic value of these new parameters remains to be established.

Biomarkers↗

PubMed1986

The role of carbohydrate in maintaining extensin in an extended conformation.

Monomers of the plant cell wall glycoprotein extensin are secreted into the wall where they become cross-linked to each other to form a rigid matrix. Expression of the extensin matrix is correlated with the inhibition of further cell elongation during normal development, with increased resistance to virulent pathogens and with other physiological responses characterized by wall strengthening. Carbohydrates make up about two-thirds of the mass of extensin. Arabinose oligomers linked to hydroxyproline residues represent 95% of the total carbohydrate with the remainder occurring as single residues of galactose linked to some serine residues. Electron microscopy of shadowed extensin shows the glycosylated form to be an easily visualized and highly elongated molecule. In contrast, extensin that has been deglycosylated with anhydrous hydrogen fluoride is difficult to resolve in the EM. Glycosylated extensin elutes from a gel filtration column much more rapidly than does the deglycosylated form, and from this analysis we have calculated respective Stokes' radii of 89 and 11 Angstroms for these molecules. Others have shown that inhibition of extensin glycosylation has no effect on its secretion or insolubilization in the cell wall, but that this extensin cannot inhibit cell elongation. It is likely that carbohydrate moieties keep extensin in an extended conformation and that extensin must be in this conformation to form a cross-linked matrix that can function properly in vivo.

Journal Article↗

PubMed2006

Urine cartilage oligomeric matrix protein (COMP) measurement is useful in discriminating the osteoarthritic Thoroughbreds.

OBJECTIVE: To quantify the urinary concentration of cartilage oligomeric matrix protein (COMP), and to evaluate the relationship between urinary COMP concentration and the catabolic activity of synovial fluid (SF) in diseased horses. METHODS: COMP in horse urine was detected by immunoblotting with a monoclonal antibody (mAb; 14G4) raised against equine COMP from articular cartilage. Urine and serum samples were obtained from 83 Thoroughbred horses with aseptic joint diseases (AJD, 79 horses) or septic joint diseases (SJD, four horses) at the time of anesthesia induction, and samples of SF were obtained during surgery. Control samples of urine (n=111) were collected from normal horses free of any orthopedic diseases after they had been racing. COMP concentration was determined in all samples using inhibition enzyme-linked immunosorbent assay (ELISA) with mAb 14G4. SF samples were also used for the quantification of gelatinase activity. RESULTS: Positive bands of COMP fragments were determined on the immunoblots with mAb 14G4. The urinary COMP concentrations in AJD and SJD horses (1.02+/-0.75 and 1.55+/-1.17 microg/100mg creatinine, respectively) were significantly higher than normal (0.57+/-0.29 microg/100mg creatinine). In 55 horses with fractures in the AJD group there was a logarithmic relationship (r=-0.45, P<0.001) between the urinary and SF COMP measurements, while the urinary COMP level was positively correlated with matrix metalloproteinase (MMP)-2 and -9 activities (r=0.30, P<0.05 and r=0.51, P<0.001, respectively) in SF. CONCLUSIONS: The urinary COMP assay with mAb 14G4 is useful for discriminating horses with osteoarthritis. The higher COMP levels in urine from such horses would be indicative of enhanced proteolytic activity, in addition to the increased COMP levels in the diseased joints.

Animals↗

PubMed2004

Serum levels of matrix extracellular phosphoglycoprotein (MEPE) in normal humans correlate with serum phosphorus, parathyroid hormone and bone mineral density.

Matrix extracellular phosphoglycoprotein (MEPE), a member of the Small Integrin Binding Ligand N-linked Glycoprotein (SIBLING) family, is primarily expressed in normal bone and has been proposed as a phosphaturic factor because of high expression and secretion in oncogenic hypophosphatemic osteomalacia tumors. In order to begin to address the role of MEPE in normal human physiology, we developed a competitive ELISA to measure serum levels of MEPE. The ELISA was used to characterize the distribution pattern in a population consisting of 114 normal adult subjects. The mean value of MEPE was 476 +/- 247 ng/ml and levels decreased significantly with increasing age. MEPE levels were also significantly correlated with serum phosphorus and parathyroid hormone (PTH). In addition, MEPE levels correlated significantly with measures of bone mineral density in the femoral neck and total hip in a subset of 50 elderly subjects. The results are consistent with MEPE being involved in phosphate and bone metabolism in a normal population.

Adult↗

PubMed1976

Spike initiation by transmembrane current: a white-noise analysis.

1. Those features of a transmembrane current correlated with spike initiation were examined in Aplysia neurones using a Gaussian white-noise stimulus. This stimulus has the advantages that it presents numerous wave forms in random order without prejudgement as to their efficacies, and that it allows straightforward statistical calculations. 2. Stimulation with a repeating segment of Gaussian white-noise current revealed remarkable invariance in the firing times of the tested neurones and indicated a high degree of reliability of their response. 3. Frequencies (less than 5 Hz) involved in spike triggering propagated faithfully for up to several millimetres, justifying intrasomatic current injection to examine spike initiation at the trigger locus. 4. Examination of current wave forms preceding spikes indicated that a wide variety could be effective. Hence, a statistical analysis was performed, including computation of probability densities, averages, standard deviations and correlation coefficients of pairs of current values. Each statistic was displayed as a function of time before the spike. 5. The average current trajectory preceding a spike was multiphasic and depended on the presence and polarity of a d.c. bias. An early relatively small inward- or outward-going phase was followed by a large outward phase before the spike. The early phase tended to oppose the polarity of the d.c. bias. 6. The late outward phase of the average current trajectory reached a maximum 40--75 msec before triggering the action potential (AP) and returned to near zero values at the moment of triggering. The fact that the current peak occurs in advance of the AP may be partially explained by a phase delay between the transmembrane current and potential. The failure of the average current trajectory to return to control values immediately following the peak argues for a positive role of the declining phase in spike triggering. 7. Probability densities preceding spikes were Gaussian, indicating that the average was also the most probable value. Although the densities were broad, confirming that spikes were preceded by a wide variety of current wave forms, their standard deviations were reduced significantly with respect to controls, suggesting preferred status of the average current trajectory in spike triggering. 8. The matrix of correlation coefficients between current pairs suggested that spikes tended to be preceded by wave forms that in part kept close to the average current trajectory and in part preserved its shape. 9. The average first and second derivatives of spike-evoking epochs revealed that current slope and acceleration, respectively, were most crucial in the last 200 msec before spike triggering, and that these dynamic stimulus components were more important for a cell maintained under a depolarizing, rather than a hyperpolarizing bias. 10...

Action Potentials↗

PubMedDate not supplied

Molecular and cellular characterization during chondrogenic differentiation of adipose tissue-derived stromal cells in vitro and cartilage formation in vivo.

Human adipose tissue is a viable source of mesenchymal stem cells (MSCs) with wide differentiation potential for musculoskeletal tissue engineering research. The stem cell population, termed processed lipoaspirate (PLA) cells, can be isolated from human lipoaspirates and expanded in vitro easily. This study was to determine molecular and cellular characterization of PLA cells during chondrogenic differentiation in vitro and cartilage formation in vivo. When cultured in vitro with chondrogenic medium as monolayers in high density, they could be induced toward the chondrogenic lineages. To determine their ability of cartilage formation in vivo, the induced cells in alginate gel were implanted in nude mice subcutaneously for up to 20 weeks. Histological and immunohistochemical analysis of the induced cells and retrieved specimens from nude mice at various intervals showed obviously cartilaginous phenotype with positive staining of specific extracellular matrix (ECM). Correlatively, results of RT-PCR and Western Blot confirmed the expression of characteristic molecules during chondrogenic differentiation namely collagen type II, SOX9, cartilage oligomeric protein (COMP) and the cartilage-specific proteoglycan aggrecan. Meanwhile, there was low level synthesis of collagen type X and decreasing production of collagen type I during induction in vitro and formation of cartilaginous tissue in vivo. These cells induced to form engineered cartilage can maintain the stable phenotype and indicate no sign of hypertrophy in 20 weeks in vivo, however, when they cultured as monolayers, they showed prehypertrophic alteration in late stage about 10 weeks after induction. Therefore, it is suggested that human adipose tissue may represent a novel plentiful source of multipotential stem cells capable of undergoing chondrogenesis and forming engineered cartilage.

Adipose Tissue↗

PubMed1989

Relationship of the demonstration of intermediate filament protein to kinetics of three human neuroepithelial tumor cell lines. Lack of neural-related proteins in most cells in S phase: a double-labeled immunohistochemical study on matrix cultures.

The immunocytochemical demonstration of intermediate filament proteins in three human neuroepithelial tumor cell lines maintained in vitro on a three-dimensional matrix was correlated with the proportion of cells in S phase. The cell lines of a medulloblastoma (D283 Med), a retinoblastoma (WERI-Rb1), and an astrocytic glioma (U-251 MG) were cultured in an organ culture system, pulse-fed with bromodeoxyuridine, and double-labeled by immunoperoxidase and by the avidin-biotin peroxidase complex method for bromodeoxyuridine and for intermediate filament proteins [each triplet of neurofilament proteins, as well as vimentin and glial fibrillary acidic (GFA) protein] using eight different antibodies. The average percentages of bromodeoxyuridine-labeled cells for the D283 Med, WERI-Rb1, and U-251 MG lines were respectively, 25, 32, and 12% 30 minutes after pulse labeling. In the D283 Med line, 15- greater than 95% of the cells were positive for each neurofilament protein, and 80% of the cells were positive for vimentin; less than 10% of the cells in S phase were positive with each of the five antineurofilament protein monoclonal antibodies (Mabs), but 20% of the vimentin-positive cells were in S phase. In the WERI-Rb1 line, 44 and greater than 96% of the cells were positive for the high-molecular-weight neurofilament subunit and high- and middle-molecular-weight neurofilament subunits proteins, respectively, but only 5% of the high-molecular-weight neurofilament positive cells were in S phase. In the U-251 MG line, 37 and 98% of the cells were positive for GFA protein and vimentin, respectively; only 3% of the GFA protein-positive cells, but 13% of the vimentin-positive cells, were in S phase. The results indicate that, when maintained in a matrix culture system, most cells in S phase in these lines lack markers of neural differentiation.

Astrocytoma↗

PubMed1998

Automation of data collection for matrix-assisted laser desorption/ionization mass spectrometry using a correlative analysis algorithm.

Automation of data collection in matrix-assisted laser desorption/ionization (MALDI) mass spectrometry using a correlative analysis algorithm is demonstrated. This algorithm was employed to compensate for mass spectral jittering in MALDI data collection (e.g., peak shifts along the m/z axis, signal intensity deviations, etc.). Several important parameters for performing correlative analysis, such as the minimum correlation coefficient to be used and number of mass spectra to acquire prior to correlation, have been investigated and optimized. In addition, the correlation algorithm improved mass resolution of low- and high-molecular-weight compounds by as much as a factor of 4. Signal reproducibility in MALDI quantitative analysis also is improved when correlation is employed for data collection. This data collection algorithm can be used in conjunction with other instrumental optimization programs to allow for fully automated MALDI analysis, which is required for the routine applications carried out in many analytical laboratories.

Algorithms↗

PubMed1986

Factor structure of the Hansburg Separation Anxiety Test.

This study examines two questions related to Hansburg's Separation Anxiety Test: To what extent can Hansburg's (1980a) matrix of correlations between theoretical factors be replicated in an independent sample? How closely do empirically derived factors from a factor analysis of test scales resemble the composition of Hansburg's theoretically based factors? A total of 135 New Zealand university students were given the Hansburg Separation Anxiety Test. Results provide minimal empirical support for Hansburg's theoretically based psychological systems factors. Additional factor replication studies with larger samples are needed to clarify the underlying empirical structure of the Separation Anxiety Test.

Adolescent↗