bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calcium oxalate crystals in fetal bovine serum: Implications for cell culture, phagocytosis and biomineralization studies in vitro
Authors: Pedraza Claudio E. , Chien Yung‐Ching , McKee Marc D. 
Published: September 2007

AbstractCell culture methods and models are key investigative tools for cell and molecular biology studies. Fetal bovine serum (FBS) is commonly used as an additive during cell culture since its constituents promote cell survival, proliferation and differentiation. Here we report that commercially available FBS from different major suppliers consistently contain precipitated, calcium oxalate crystals—either in the monohydrate (COM) or dihydrate (COD) form. Mineral structure and phase identification of the crystals were determined by X‐ray diffraction, chemical composition by energy‐dispersive X‐ray microanalysis, and imaging and measurement of crystal growth steps by atomic force microscopy—all identified and confirmed crystallographic parameters for COM and COD. Proteins binding to the crystals were identified by immunoblotting, revealing the presence of osteopontin and fetuin‐A (α2HS‐glycoprotein)—known regulators of crystal growth found in serum. Macrophage cell cultures exposed to calcium oxalate crystals showed internalization of the crystals by phagocytosis in a process that induced disruption of cell–cell adhesion, release of reactive oxygen species and membrane damage, events that may be linked to the release of inflammatory cytokines by these cells into the culture media. In conclusion, calcium oxalate crystals found in commercially available FBS are toxic to cells, and their presence may confound results from in vitro studies where, amongst others, phagocytosis, biomineralization, renal cell and molecular biology, and drug and biomaterial testing are being examined. J. Cell. Biochem. 103: 1379–1393, 2008. © 2007 Wiley‐Liss, Inc.
Histone H1.2 is translocated to mitochondria and associates with bak in bleomycin‐induced apoptotic cells
Authors: Okamura Hirohiko , Yoshida Kaya , Amorim Bruna Rabelo , Haneji Tatsuji 
Published: September 2007

AbstractBleomycin induces single‐ and double‐stranded breaks in DNA, with consequent mitochondrial membrane aberrations that lead to the apoptotic cell death. It is poorly understood how DNA damage‐inducing apoptotic signals are transmitted to mitochondria, from which apoptotic factors are released into the cytoplasm. Here, we investigated the localization of histone H1.2 in the bleomycin‐treated human squamous carcinoma SCCTF cells. The presence of DNA double‐strand breaks in the bleomycin‐treated cells was examined by Western analysis using antibody against phosphorylated histone H2AX (γ‐H2AX). Incubation of SCCTF cells for 48 h with 10 µM bleomycin induced apoptosis, as determined by cleavage of lamin B1 to 28 kDa fragment and DNA ladder formation. The mitochondrial permeabilization causing apoptotic feature was also detected with MitoCapture in the bleomycin‐treated cells. Histone H1.2 was translocated from the nucleus to the mitochondria after treatment with bleomycin and co‐localized with Bak in mitochondria. Our present results suggest that histone H1.2 plays an important role in transmitting apoptotic signals from the nucleus to the mitochondria following double‐stranded breaks of DNA by bleomycin. J. Cell. Biochem. 103: 1488–1496, 2008. © 2007 Wiley‐Liss, Inc.
Catalase overexpression impairs TNF‐α induced NF‐κB activation and sensitizes MCF‐7 cells against TNF‐α
Authors: Lüpertz Regine , Chovolou Yvonni , Kampkötter Andreas , Wätjen Wim , Kahl Regine 
Published: September 2007

AbstractThe pleiotropic cytokine tumor necrosis factor alpha (TNF‐α) can induce apoptosis but also supports cell survival pathways. Among the possible anti‐apoptotic mechanisms of TNF‐α is the activation of the transcription factor NF‐κB. Since reactive oxygen species (ROS) are assumed to contribute to TNF‐α mediated cytotoxicity but can also facilitate NF‐κB activation this study investigates the relationship between TNF‐α treatment, NF‐κB activation and the expression of the anti‐oxidative enzyme catalase. TNF‐α treatment caused downregulation of catalase expression in MCF‐7, Caco‐2 and Hct‐116 cancer cell lines. Overexpression of catalase in MCF‐7 cells, resulting in lower intracellular ROS levels upon challenge with H2O2, caused a transient nuclear p65 translocation upon TNF‐α treatment as compared to the sustained NF‐κB activation in wild type cells. This was due to a lack of sufficient H2O2 to co‐stimulate NF‐κB activation as demonstrated by the observation that addition of exogenous H2O2 led to a second increase of NF‐κB activity. The rapid decline of nuclear translocation of NF‐κB in the catalase overexpressing cells resulted in a slower increase of NF‐κB mediated reporter gene expression. These results indicate that TNF‐α mediated downregulation of catalase expression and accordingly sufficient H2O2 is required for appropriate function of the NF‐κB dependent survival pathway. J. Cell. Biochem. 103: 1497–1511, 2008. © 2007 Wiley‐Liss, Inc.
The vitamin D receptor‐mediated activation of phosphatidylinositol 3‐kinase (PI3Kα) plays a role in the 1α,25‐dihydroxyvitamin D3‐stimulated increase in steroid sulphatase activity in myeloid leukaemic cell lines
Authors: Hughes Philip J. , Lee Jimmy S. , Reiner Neil E. , Brown Geoffrey 
Published: September 2007

AbstractIn this article we show that 1α,25‐dihydroxyvitamin D3 (1α,25(OH)2D3) stimulates the activity of the class IA phosphatidylinositol 3‐kinase PI3Kα and its downstream target Akt in HL60, U937 and THP‐1 myeloid leukaemic cell lines. Furthermore, we show that the classical nuclear vitamin D receptor (VDRnuc) is involved in this activation of the PI3K/Akt signalling in these cell lines. We have previously shown that the activity of steroid sulphatase is stimulated in HL60, U937 and THP‐1 myeloid leukaemic cell lines by 1α,25(OH)2D3 (Hughes et al., [2001] Biochem J 355:361–371; Hughes et al., [2005] J Cell Biochem 94:1175–1189; Hughes and Brown [2006] J Cell Biochem 98:590–617). In this article we show that the 1α,25(OH)2D3‐stimulated increase in signalling via the PI3K/Akt pathway plays a role in the increase in steroid sulphatase activity in the HL60 U937 and THP‐1 cell lines. We used a variety of pharmacological and biochemical approaches to show that activation of PI3Kα mediates the 1α,25(OH)2D3‐stimulated increase in steroid sulphatase activity in myeloid leukaemic cells. We also show that the PI3K/Akt dependent activation of NF‐κB plays a role in the 1α,25(OH)2D3‐stimulated increase in steroid sulphatase activity in myeloid leukaemic cells. J. Cell. Biochem. 103: 1551–1572, 2008. © 2007 Wiley‐Liss, Inc.
Mouse spermatozoa contain a nuclease that is activated by pretreatment with EGTA and subsequent calcium incubation
Authors: Boaz Segal M. , Dominguez Kenneth , Shaman Jeffrey A. , Ward W. Steven 
Published: September 2007

AbstractWe demonstrated that mouse spermatozoa cleave their DNA into ∼50 kb loop‐sized fragments with topoisomerase IIB when treated with MnCl2 and CaCl2 in a process we term sperm chromatin fragmentation (SCF). SCF can be reversed by EDTA. A nuclease then further degrades the DNA in a process we term sperm DNA degradation (SDD). MnCl2 alone could elicit this activity, but CaCl2 had no effect. Here, we demonstrate the existence of a nuclease in the vas deferens that can be activated by ethylene glycol tetraacetic acid (EGTA) to digest the sperm DNA by SDD. Spermatozoa were extracted with salt and dithiothreitol to remove protamines and then incubated with EGTA. Next, the EGTA was removed and divalent cations were added. We found that Mn2+, Ca2+, or Zn2+ could each activate SDD in spermatozoa but Mg2+ could not. When the reaction was slowed by incubation on ice, EGTA pretreatment followed by incubation in Ca2+ elicited the reversible fragmentation of sperm DNA evident in SCF. When the reactions were then incubated at 37°C they progressed to the more complete degradation of DNA by SDD. EDTA could also be used to activate the nuclease, but required a higher concentration than EGTA. This EGTA‐activatable nuclease activity was found in each fraction of the vas deferens plasma: in the spermatozoa, in the surrounding fluid, and in the insoluble components in the fluid. These results suggest that this sperm nuclease is regulated by a mechanism that is sensitive to EGTA, possibly by removing inhibition of a calcium binding protein. J. Cell. Biochem. 103: 1636–1645, 2008. © 2007 Wiley‐Liss, Inc.
Serine protease inhibitors N‐α‐Tosyl‐L‐Lysinyl‐Chloromethylketone (TLCK) and N‐Tosyl‐L‐Phenylalaninyl‐Chloromethylketone (TPCK) are potent inhibitors of activated caspase proteases
Authors: Frydrych Ivo , Mlejnek Petr 
Published: September 2007

AbstractSerine protease inhibitors N‐α‐tosyl‐L‐lysinyl‐chloromethylketone (TLCK) and N‐tosyl‐L‐phenylalaninyl‐chloromethylketone (TPCK) exhibit multiple effects on cell death pathways in mammalian cells. Thus, they are able to induce apoptosis by itself or promote cell death induced by other cytotoxic stimuli [King et al., 2004; Murn et al., 2004]. On the other hand, TLCK and TPCK were reported to prevent apoptosis by inhibiting the processing of caspases in response to some cell death inducing stimuli [Stefanis et al., 1997; Jones et al., 1998]. We observed that the pretreatment of HL‐60 cells with TLCK or TPCK diminished caspases 3 and ‐7 (DEVDase) and caspase‐6 (VEIDase) activity in response to various cell death inducing stimuli such as staurosporine (STS), etoposide (ETP), or N6‐(2‐isopentenyl)adenosine. In addition, TLCK but not TPCK inhibited collapse of mitochondrial transmembrane potential ΔΨm (delta psi) in dying HL‐60 cells. Such effects used to be considered as protective, however, the protection was only presumable since neither TLCK nor TPCK actually prevented cells from death. Our results further indicated that serine protease inhibitors TLCK and particularly TPCK acted as efficient direct inhibitors of mature caspases. Indeed, experiments with human recombinant caspases provided unequivocal evidence that TLCK and TPCK are very potent but non‐specific inhibitors of activated caspases, namely caspases 3, ‐6, and ‐7. Interestingly, TPCK exhibited similar efficiency towards human recombinant caspases to that found for panspecific caspase inhibitor Boc‐D‐CMK. Such properties of TLCK and TPCK, previously considered as specific inhibitors of serine proteases, might offer novel consistent explanation for several protective or protective‐like effects on apoptotic cells. J. Cell. Biochem. 103: 1646–1656, 2008. © 2007 Wiley‐Liss, Inc.
p63 in prostate biology and pathology
Authors: Grisanzio Chiara , Signoretti Sabina 
Published: September 2007

AbstractThe identification of stem cells and differentiation programs regulating the development and maintenance of the normal prostate epithelium is essential for the identification of the cell type(s) and molecular alterations involved in the development and propagation of prostate cancer (CaP). The p53‐homologue p63 is highly expressed in normal prostate basal cells and is a clinically useful biomarker for the diagnosis of CaP. Importantly, p63 has been shown to play a critical role in prostate development. Recent experimental evidence also suggests that this gene is essential for normal stem cell function in the prostate as well as other epithelial organs. Future studies aimed at better defining the role of p63 in the renewal of the adult prostate epithelium are likely to shed new light on the mechanisms involved in prostate carcinogenesis. J. Cell. Biochem. 103: 1354–1368, 2008. © 2007 Wiley‐Liss, Inc.
The use of solvent isotope effects in the pursuit of enzyme mechanisms
Authors: Schowen Richard L. 
Published: September 2007

AbstractThe basic principles and illustrative applications to enzyme mechanisms of solvent isotope effects, with emphasis on the use of rate measurements in mixtures of protium and deuterium oxides (‘proton inventories’), are reviewed over a period slightly shorter than the history of this Journal. The principles in their current formulation are traced to publications of the 1960s and the illustrations are taken from publications that have appeared in 2006–2007. Copyright © 2007 John Wiley & Sons, Ltd.
Isotope effects for fluorine‐18 and carbon‐11 in the study of reaction mechanisms
Authors: Matsson Olle , MacMillar Susanna 
Published: September 2007

AbstractThe use of kinetic isotope effects (KIEs) for the short‐lived radionuclides 11C and 18F in the study of reaction mechanisms is described using some examples. Leaving group fluorine KIEs (k18/k19) have been utilized to determine the rate‐limiting step for nucleophilic aromatic substitution reactions (SNAr). The fluorine KIE was also used to probe the effect of changing solvent and nucleophile steric hindrance on rate‐limiting step. The mechanism for a base promoted elimination reaction was determined to be stepwise (E1cB) by a multiple KIE study including the leaving group fluorine KIE. The transition state structures for aliphatic nucleophilic substitution reactions (SN2) have been investigated by multiple KIE studies for cases where the substrate substitution, leaving group or solvent has been varied. Carbon KIEs for labelled α‐carbon atom in the substrate are large, k11/k14 = 1.189–1.220. For labelled nucleophile cyanide ion, k11/k14 = 0.99951–1.0119. Copyright © 2007 John Wiley & Sons, Ltd.
The synthesis of tritiated (R)‐2‐methoxy‐N‐n‐propyl‐nor‐apomorphine (MNPA)
Authors: Malmquist Jonas , Olofsson Susanne , Ström Peter 
Published: September 2007

AbstractA method for the preparation of [3H]‐MNPA ((R)‐2‐methoxy‐N‐n‐propyl‐norapomorphine) has been developed addressing the regioisomer problem as well as the oxidation problem. (R)‐2, 10, 11‐trihydroxy‐N‐n‐propyl‐norapomorphine was protected with 10, 11‐dibenzyl or 10, 11‐acetonide. The pure precursor was then methylated using [3H]‐methyliodide. The product was isolated after deprotection and high‐pressure liquid chromatography (HPLC) purification. Ascorbic acid was used as an antioxidant in the HPLC eluent and the stock solution. Characterization of the intermediates and products with 3H‐ and 1H‐NMR was performed. A specific activity of 3.1 TBq/mmol (83.8 Ci/mmol) and 98.9% purity was obtained. Copyright © 2007 John Wiley & Sons, Ltd.
Using residue sums to estimate high‐order Fourier harmonics of piecewise‐continuous transcendental functions: Application to Class A‐, B‐ and F‐type amplifier circuits
Authors: Kenny R. G. 
Published: September 2007

AbstractA discrete fast‐Fourier transform (DFFT) is the preferred method of choice for the rapid evaluation of a set of harmonics of a piecewise‐continuous and periodic transcendental form. For large sets of Fourier components specified to some stringent error criterion, the approach becomes increasingly unattractive owing to the presence of round‐off errors that result from the switching of one transcendental form to another. As an alternative, it might be wondered whether the high‐frequency components can be more efficiently estimated by employing a combination of residue sums and boundary integrals in the complex plane z = Reiωt, where ω is the fundamental frequency and R = ∣z∣.The starting point is the construction of suitable contours that divide the complex plane into a number of sectors in accordance with the number of intervals of smooth behaviour of a periodic piecewise‐continuous real function along ∣z∣ = 1. Each sector encompasses the analytic extension of a real transcendental function on ∣z∣ = 1 to yield p(z)T(f(z)), where T(ζ) is meromorphic and p(z), f(z) are Laurent series. Fourier coefficients are subsequently expressed in terms of residue series and constant‐phase boundary integrals from each of the various sectors associated with a given p(z)T(f(z)). This approach is applied to the model for the drain current of a field effect transistor (FET), where in this case T(ζ) = tanh(ζ), which is subject to the modes of operation: ‘Class A’, ‘Class B’ and approximate ‘Class F’. In contrast to Classes A and B, the Fourier coefficients in the ‘Class F’ drain current decay slowly with frequency, suggesting that this mode might be more suitably analysed using a combined DFFT/residue procedure. Copyright © 2007 John Wiley & Sons, Ltd.
Antioxidant capacity of leafy vegetables as affected by high tunnel environment, fertilisation and growth stage
Authors: Zhao Xin , Iwamoto Takeo , Carey Edward E 
Published: September 2007

AbstractBACKGROUND: This study was conducted to evaluate the influences of protected environment, organic fertilisation and growth stage on the oxygen radical absorbance capacity (ORAC) values of leafy vegetables.RESULTS: In a first experiment, pac choi grown in high tunnels had significantly lower ORAC than field‐grown plants. Organic fertiliser markedly increased the antioxidant capacity of pac choi compared with conventional treatment, especially in the open field. However, both open field and organic production resulted in significantly lower yield and more severe leaf damage due to insect attack. In a second study, spinach showed the highest ORAC, followed by pac choi, red leaf lettuce and romaine lettuce. A significant decline in ORAC under high tunnel production was observed only in spinach. In contrast to the first trial, organic fertilisation did not cause an increase in antioxidant capacity of the leafy vegetables. The ORAC values of spinach from the open field and pac choi from high tunnels were significantly higher when harvested at the mature head stage than at the baby size stage.CONCLUSION: Further studies will help to elucidate effects of genotype, growth stage, and production environment on antioxidant capacities of vegetables and may lead to recommended practices to maximise antioxidant capacity of vegetable crops. Copyright © 2007 Society of Chemical Industry
Content composition and antioxidant activity of isoflavones in commercial and homemade soymilk and tofu
Authors: Ishihara Michiko , Singh Harmit , Chung Glen , Tam Chick 
Published: September 2007

AbstractBACKGROUND: Isoflavones, found in soymilk and tofu, are one of the phytochemicals in soy‐based products that may promote good health. Homemade tofu and various homemade soymilk samples were made using different soaking, grinding, and cooking methods. The homemade samples were compared to commercial tofu and soymilk for total isoflavone content and composition as well as their antioxidant capacity. All samples were freeze‐dried and extracted with a 58% acetonitrile solution which was subsequently used to determine the isoflavone content by reverse‐phase high‐performance liquid chromatography. The antioxidant activity of extracts was determined using a modified 2,2‐azino‐bis‐(3‐ethylbenzthiazoline‐6‐sulfonic acid) method and total antioxidant capacity was reported as ascorbic acid equivalents.RESULTS: The total isoflavone, aglycone, and antioxidant levels were significantly higher in homemade soymilk and tofu (1571 µg) than in commercial samples. Homemade soymilk made by the extended boiling method yielded the highest total isoflavone (2567 µg) and glucoside (1525 µg) content. A strong positive correlation was observed between the total isoflavone, aglycone conjugates, and genistein series concentration and antioxidant capacity of soymilk.CONCLUSION: Increased moist heating time yielded the highest concentration of total isoflavones as well as aglycone conjugates and the genistein series. Increasing the duration of boiling can increase the isoflavone content of both homemade and commercial soymilk and tofu. Copyright © 2007 Society of Chemical Industry
Gelatine–starch films: Physicochemical properties and their application in extending the post‐harvest shelf life of avocado (Persea americana)
Authors: Aguilar‐Méndez Miguel A , Martín‐Martínez Eduardo San , Tomás Sergio A , Cruz‐Orea Alfredo , Jaime‐Fonseca Mónica R 
Published: September 2007

AbstractBACKGROUND: Several storage techniques have been developed to extend the post‐harvest shelf life of horticultural products. One method involves the use of edible or biodegradable coatings. Such coatings are made of biological materials that are used to coat fresh products, providing a semi‐permeable barrier to water vapour and gases, e.g. O2 and CO2. The influence of starch concentration, glycerol content and pH on the carbon dioxide permeability (CO2P) and mechanical properties of gelatine–starch edible films were evaluated.RESULTS: Results showed that increments in the starch concentration and pH resulted in higher CO2P values. Film puncture strength increased when the starch concentration decreased and the maximum resistance value (32.6 N) was obtained at pH 6. Deformation was mainly affected by glycerol and starch content. Some films were chosen in order to evaluate their effect, as coatings, in the post‐harvest shelf life of avocados (Persea americana Mill c.v. Hass). Fruits were immersed in the coating solutions, air dried and stored at two temperatures. Changes in colour, weight loss and pulp firmness were determined in fruits stored at 6 °C. In addition, respiration rate was measured in avocados kept at 20 °C.CONCLUSION: The application of gelatine–starch coatings delayed the ripening process of avocados, as indicated by a better pulp firmness and retention of skin colour, and lower weight loss of coated fruits in comparison with control avocados. The coatings also resulted in a delayed respiratory climacteric pattern, by 3 days, for coated fruits. Copyright © 2007 Society of Chemical Industry
Synergism between lipoxygenase‐active soybean flour and ascorbic acid on rheological and sensory properties of wheat bread
Authors: Junqueira Roberto M , Cocato Maria L , Colli Célia , Castro Inar A 
Published: September 2007

AbstractBACKGROUND:The interaction between lipoxygenase‐active soybean flour (LOX) and ascorbic acid (AA), on colour, rheological and sensory properties of wheat bread was studied with the aim of reducing the applied quantity of additives in bread formulations.RESULTS:The ascorbic acid (0–500 ppm) and active soybean flour (0–1%) mixture improved bread‐crumb colour by lowering the yellow hue in a higher proportion than those expressed by the components alone, characterising a synergistic mechanism (ŷb= 15.1− (1.7 × LOX) − (0.5 × AA) − (5.8 × LOX × AA), whereŷbrepresent the estimated value for the yellow hue parameter). No differences in flavour and porosity were seen between the samples. As supported by the instrumental methods, breads made with active soybean flour and ascorbic acid (LOX + AA) had whiter crumbs and were softer and springier than controls as assessed by a trained sensory panel. In summary, the combination of both active soybean flour and ascorbic acid showed synergism, promoting a greater bleaching effect than when used alone.CONCLUSION:These results suggest the potential use of active soybean flour as a synergistic ingredient in the substitution of artificial additives in bread making. Since the interaction on the bleaching response was not linear and active soybean flour showed a higher iron concentration (66.40 ± 4.23 µg g−1) than non‐active soybean flour (52.30 ± 0.40 µg g−1), more studies are warranted to establish the biochemical mechanisms involved in this interaction. Copyright © 2007 Society of Chemical Industry