bluuebunny/crossref_metadata_2025 huggingface dataset:
Direct toxicity assessment of wastewater: Baroxymeter, a portable rapid toxicity device and the industry perspective
Authors: Tzoris Achilles , Fearnside David , Lovell Matthew , Hall Elizabeth A. H.
Published: October 2002

Direct toxicity assessment of wastewater is becoming necessary, and new legislation may render it compulsory for the water industry. At present such assessment is performed at a laboratory away from a site, at considerable cost, and results often come too late, after a toxic event has occurred and the toxin has been released into the environment. Some of the rapid toxicity tests available today require certain conditions to function properly, or their results do not always correlate with other methods. The objective of this study was to assess a portable device, the Baroxymeter, for its suitability as an instrument to test wastewater toxicity. The way the device works is based on monitoring respiration of a bacterial culture by pressure measurements and using respiration inhibition as a toxicity alert. It has been shown that it is possible to detect toxic substances such as 3,5‐dichlorophenol and bronopol within 5 min from a 1‐mL sample. The benefits and future applications of the Baroxymeter as a high‐throughput, cost‐effective alternative for toxicity screening are discussed in this article. © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 284–290, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10059
Genotoxicity of cyanobacterial extracts containing microcystins from Polish water reservoirs as determined by SOS chromotest and comet assay
Authors: Mankiewicz Joanna , Walter Zofia , Tarczynska Malgorzata , Palyvoda Olena , Wojtysiak‐Staniaszczyk Magdalena , Zalewski Maciej
Published: October 2002

Toxicity of cyanobacterial blooms, an increasing problem around the world, is connected to the increase in bloom samples containing microcystins, caused by excessive eutrophication of drinking‐ and recreational water reservoirs. Microcystins are the most common group of cyanobacterial hepatotoxins. In Poland they are produced mainly by the Microcystis genus. The toxicity of microcystins has been well documented, but investigation into their genotoxicity has been insufficient relative to the study of their overall toxicity. Therefore, the aim of this study was the estimation and comparison of the genotoxicity of cyanobacterial extracts with microcystins (CEMs) using the SOS chromotest (bacterial test) with Escherichia coli PQ37 and the comet assay with human lymphocytes. Cyanobacterial bloom samples were collected in the summer months from two Polish water reservoirs, one at Sulejów and one at Jeziorsko. The SOS chromotest, which used prokaryotic cells (without metabolic activation), and the comet assay, which used eukaryotic cells, both indicated the potential genotoxic effect of CEMs. Cyanobacterial extracts caused DNA damage in human lymphocytes in vitro. The maximum level of DNA damage was observed after 12 h incubation with CEMs. The bacterial test indicated a dependence of the degree of CEM genotoxicity, the composition, and the concentration of microcystins in each bloom sample examined with the time of exposure. Differences between the genotoxicity of cyanobacterial extract and the standard microcystin‐LR were noticeable. This was probably caused by the interaction of different microcystin variants. The results showed that CEMs from Polish water reservoirs were genotoxic, which was reflected by the stimulation of the SOS repair system in bacterial cells (SOS chromotest) and by the damage induced in DNA in human lymphocytes (comet assay). © 2002 Wiley Periodicals, Inc. Environ Toxicol 17: 341–350, 2002; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/tox.10061
Projected slabs: approximation of perspective projection and error analysis
Authors: Vilanova Bartrolí A. , Wegenkittl R. , Gröller E.
Published: October 2002

Virtual endoscopy is a promising medical application for volume‐rendering techniques where perspective projection is mandatory. Most of the acceleration techniques for direct volume rendering use parallel projection. This paper presents an algorithm to approximate perspective volume rendering using parallel projected slabs. The introduced error due to the approximation is investigated. An analytical study of the maximum and average error is made. This method is applied to VolumePro 500. Based on the error analysis, the basic algorithm is improved. This improvement increases the frame rate, keeping the global maximum error bounded. The usability of the algorithm is shown through the virtual endoscopic investigation of various types of medical data sets. Copyright © 2002 John Wiley & Sons, Ltd.
The creation of a high‐fidelity finite element model of the kidney for use in trauma research
Authors: Snedeker J. G. , Bajka M. , Hug J. M. , Székely G. , Niederer P.
Published: October 2002

A detailed finite element model of the human kidney for trauma research has been created directly from the National Library of Medicine Visible Human Female (VHF) Project data set. An image segmentation and organ reconstruction software package has been developed and employed to transform the 2D VHF images into a 3D polygonal representation. Non‐uniform rational B‐spline (NURBS) surfaces were then mapped to the polygonal surfaces, and were finally utilized to create a robust 3D hexahedral finite element mesh within a commercially available meshing software. The model employs a combined viscoelastic and hyperelastic material model to successfully simulate the behaviour of biological soft tissues. The finite element model was then validated for use in biomechanical research. Copyright © 2002 John Wiley & Sons, Ltd.
Building 3D anatomical scenes on the Web
Authors: Evesque F. , Gerlach S. , Hersch R. D.
Published: October 2002

We propose a new service for building user‐defined 3D anatomical structures on the Web. The Web server is connected to a database storing more than 1000 3D anatomical models reconstructed from the Visible Human. Users may combine existing models as well as planar oblique slices in order to create their own structured anatomical scenes. Furthermore, they may record sequences of scene construction and visualization actions. These actions enable the server to construct high‐quality video animations, downloadable by the user. Professionals and students in anatomy, medicine and related disciplines are invited to use the server and create their own anatomical scenes. Copyright © 2002 John Wiley & Sons, Ltd.
Determination of the thickness of coatings by means of a new XRF spectrometer
Authors: Fiorini C. , Gianoncelli A. , Longoni A. , Zaraga F.
Published: October 2002

We propose a new, compact XRF spectrometer conceived for the determination of the thickness of a coating deposited on a substrate. The analysis technique is based on the detection, at different angles of observation, of the fluorescence emitted by the substrate and absorbed through the coating. With respect to other methods, the measurement is independent of the XRF analysis of the coating, which need not even be fluorescent. Moreover, no calibration of the instrument with standard samples is required. A key feature of the proposed spectrometer is represented by the use of a Silicon Drift Detector (SDD) for the first time in this kind of measurement. The SDD is characterized by a very low output capacitance (of the order of 0.1 pF), independent of the active area of the device, which allows one to achieve a lower electronic noise with respect to a conventional silicon diode of equivalent area and thickness. Based on a Peltier‐cooled SDD, a compact spectrometer, characterized by an energy resolution of about 155 eV FWHM at 6 keV (at about −10°C), was realized. The analysis technique and the spectrometer compactness make this instrument suitable for on‐line, non‐destructive quality control in the semiconductor and mechanical industries. In this paper the measurement technique is described and the first experimental results obtained on samples composed of a substrate coated with a layer of different thickness are presented. Copyright © 2002 John Wiley & Sons, Ltd.
Performance of a new compact EDXRF spectrometer for aerosol analysis
Authors: Samek Lucyna , Injuk Jasna , Van Espen Piet , Van Grieken René
Published: October 2002

The performance of a compact and economic MiniPal EDXRF spectrometer (Philips Analytical, Almelo, The Netherlands) was investigated for the analysis of aerosol filters. A standard operating procedure for the XRF analysis of aerosols on filters was followed. First, different aerosol grade filters (Nuclepore, Whatman, Teflon) and Mylar foil were measured to evaluate the blank values. The initial results showed high apparent blank values of Fe, Ni, Cu and Zn for all the substrates, which was attributed to the measurement platform of the commercial system, made out of brass coated with nickel. To overcome this problem, the measurement platform was covered with high‐purity silver paint. In this way, the high blank values, introduced by the system itself, were considerably reduced. The second step was the selection of the best tube‐filter to use, among the standard ones already incorporated in the MiniPal. The optimum tube‐filters were found to be Mo and Ag for medium‐Z elements and Al for low‐Z elements. In the calibration procedure a series of thin reference standards were used. The calibration procedure was evaluated by analysing aerosol samples measured previously with a Tracor EDXRF unit. Based on the analysis of these samples, the accuracy was on average 20% depending on the element and concentration. The precision of the analysis was better than 5%. Detection limits for aerosol samples measured with the MiniPal system are in the range from 3 ng cm−2 (Al, Si) in a helium atmosphere, which is much better than with conventional EDXRF units, to 2 ng cm−2 (heavy metals), which is comparable to those for conventional EDXRF units. Measurements in a helium atmosphere were performed for both standard and aerosol samples. For light element analysis, an improvement of the detection limit by a factor of 2.5 was achieved when helium was used. Copyright © 2002 John Wiley & Sons, Ltd.
Out‐of‐school‐time programs: At a critical juncture
Authors: Shortt Joyce
Published: October 2002

The long‐term success of out‐of‐school‐time programs may be in jeopardy if they cannot build and sustain a committed and competent workforce.
Behavioral effects of environmental enrichment on harbor seals (Phoca vitulina concolor) and gray seals (Halichoerus grypus)
Authors: Hunter Sue A. , Bay Monika S. , Martin Michele L. , Hatfield Jeff S.
Published: October 2002

Zoos and aquariums have been incorporating environmental enrichment into their animal care programs for the past 30 years to increase mental stimulation and promote natural behaviors. However, most attempts to document the effects of enrichment on animal behavior have focused on terrestrial mammals. Staff at the National Aquarium in Baltimore conducted an investigation of the behavioral effects of enrichment on the seven harbor seals and two gray seals housed in the aquarium's outdoor seal exhibit. We expected that enrichment would change the amount of time the animals spent engaged in specific behaviors. The behaviors recorded were: resting in water, resting hauled out, maintenance, breeding display, breeding behavior, aggression, pattern swimming, random swimming, exploration, and out of sight. Activity levels (random swimming and exploration) were expected to increase, while stereotypic behaviors (pattern swimming) were expected to decrease. The frequency and duration of behaviors were documented for 90 hr in both the control phase (without enrichment) and the experimental phase (with enrichment). Statistically significant differences (P<0.05) in the time spent in pattern swimming, random swimming, exploration, and out of sight were observed between the two phases. With enrichment, pattern swimming and out of sight decreased, while random swimming and exploration behavior increased. These findings demonstrate that enrichment can promote behaviors (random swimming and exploration) that are likely to be normal for phocids in the wild, and that may contribute to the behavioral complexity of these seals in captivity. Zoo Biol 21:375–387, 2002. © 2002 Wiley‐Liss, Inc.
Constraints on the temperature sensitivity of global soil respiration from the observed interannual variability in atmospheric CO2
Authors: Jones Chris D. , Cox Peter M.
Published: October 2002

Carbon cycle feedbacks have been shown to be very important in predicting climate change over the next century. The response of the terrestrial carbon cycle to climate change depends on the competition between increased respiration due to warmer temperatures and increased uptake due to elevated CO2levels. Whether the terrestrial carbon cycle remains a sink for anthropogenic carbon, or switches to become a source, depends particularly on the response of soil respiration to temperature. Here we use observed global atmospheric CO2concentration to constrain the behaviour of soil respiration in a coupled climate–carbon cycle GCM. Copyright © 2001 British Crown Copyright.
Cytoskeletal changes and induction of embryogenesis in microspore and pollen cultures of Brassica napus L.
Authors: Hause B. , Hause G. , Pechan P. , van Lammeren A. A. M.
Published: October 2002

Microspores and pollen of Brassica napus were cultured under conditions leading to embryo formation. Concomitant changes in cytoskeletal configurations were analysed. The microfilamental cytoskeleton exhibited a loss of polarity in embryogenic cells but cytochalasin treatment revealed that microfilaments do not influence embryogenesis. Two embryogenic pathways started from microspores and were either characterized by turned division planes or by division when the nucleus was in the cell centre. In both cases microtubules clearly exhibited new arrangements and likely played a major role in newly induced symmetrical division. In pollen, embryogenic development started in the vegetative cell provided the generative cell was arrested near the pollen wall. The concomitant disappearance of defined microtubular arrays is likely to be responsible for the positioning of the cell.
Study of localization of the protein‐synthesizing machinery along actin filament bundles.
Authors: Shestakova Elena A. , Motuz Ludmila P. , Minin Alexander A. , Gavrilova Lydia P.
Published: October 2002

Indirect immunofluorescent microscopy was used to study the distribution of elongation factor 2 (eEF‐2) in fixed human skin diploid and mouse embryo fibroblasts. It was found earlier that some of the eEF‐2 ribosomes and initiation factor 2 (eIF‐2) are co‐localized with a part of the actin microfilament bundles in these cells (Gavrilova et al., 1987; Shestakova et al., 1991). Here it has been shown that inhibition of protein synthesis either by inactivation of eEF‐2 itself with diphtheria toxin or by inactivation of ribosomes with ricin does not abolish the distribution of eEF‐2 along the actin microfilament bundles. At the same time, the disassembly of actin microfilaments by cytochalasin D results also in the disappearance of eEF‐2‐carrying threads. This means that the eEF‐2‐carrying threads do not exist per se, and that the organization of eEF‐2 in visible "filaments" depends upon the integrity of the actin cytoskeleton.
Co‐localization of components of the protein‐synthesizing machinery with the cytoskeleton in G0‐arrested cells.
Authors: Shestakova Elena A. , Motuz Ludmila P. , Gavrilova Lydia P.
Published: October 2002

The distribution of eukaryotic elongation factor 2 (eEF‐2) in G0‐arrested fixed human skin diploid fibroblasts was studied by indirect immunofluorescent microscopy. It was found earlier that the main part of eEF‐2 in cycling cells was located near the nucleus in the endoplasm (Gavrilova et al., 1987). It has been demonstrated here that the transition from proliferation to the G0 phase of the cell cycle leads to the distribution of eEF‐2 mainly along the intermediate filaments and/or microtubules. Both in cycling and in G0‐arrested fibroblasts a portion of eEF‐2 is also co‐localized with actin microfilament bundles. The reversion of the cells from the G0 phase to proliferation is accompanied by rearrangement of the actin cytoskeleton and reversal to the original pattern of eEF‐2 distribution. It is likely that the different types of cytoskeleton in eukaryotic cells can be involved in organization of protein‐synthesizing machinery.
Changes on protein expression associated with salinity tolerance in Brassica cell cultures
Authors: Martín J. P. , Elavummoottil O. C. , Moreno M. L.
Published: October 2002

The synthesis of proteins from salt‐tolerant Brassica oleracea L. var. botrytis L. subvar. cauliflora (Gars.) DC. (cauliflower) cell cultures is modified in relation to controls in several features. There are nine newly induced polypeptides in tolerant cultures (absent in control conditions). Some of them are only present under low salt levels (85 mM NaCl). Another group seems to be representative of moderate and high salt levels (170 and 255 mM NaCl), and a third group is present in all the salt conditions tested. On the other hand, the synthesis of most of the polypeptides present in control conditions is modified in salt‐tolerant cultures by increasing, decreasing or stopping their synthesis in any of the tested conditions. The relationship between these changes in Brassica and other plant systems is discussed.
Changes in sensitivity of human tumour cells to growth inhibition by proteinase inhibitors.
Authors: Scott G. Kenneth , Tse Cynthia A.
Published: October 2002

Inhibition of a cell‐surface proteinase can inhibit the growth of many normal human cell types in culture. Some tumour cells are also sensitive to proteinase inhibitors, but others are resistant, and continue to grow in the presence of these inhibitors. Here we describe two human tumour cell lines which convert from the sensitive to the resistant state. In one case, the conversion occurs during routine passaging, but, in the other, it is determined by growth conditions, and is reversible.
SYNTHESIS OF LACTOFERRIN AND CASEIN BY EXPLANTS OF BOVINE MAMMARY TISSUE
Authors: Hurley W. L. , Aslam M. , Hegarty H. M. , Morkoç A.
Published: October 2002

Synthesis of lactoferrin and casein by the bovine mammary gland was determined in an experimental model where lactation was maintained in one mammary half, while involution was induced in the contralateral half. Culture of explants with prolactin had no consistent effect on synthesis of casein or lactoferrin in tissue from either mammary half. Endotoxin and tumor necrosis factor‐α generally decreased synthesis of casein and lactoferrin, suggesting that these inflammatory mediators are not directly responsible for increasing lactoferrin synthesis during mammary inflammation or involution. Synthesis of lactoferrin was increased and casein decreased in the involuting mammary half vs. the lactating half. These results suggest that local factors in the mammary gland play a role in the regulation of lactoferrin synthesis during involution.
Human hypertensive placenta contains an increased amount of Na, K‐ATPase with higher affinity for cardiac glycosides
Authors: Amler Evžen , Cester Nelvio , Salvolini Eleonora , Staffolani Roberto , Burkhard Martin , Mazzanti Laura , Kotyk Arnošt , Romanini Carlo
Published: October 2002

Placentas of women suffering from pregnancy‐induced hypertension (PIH) were found to contain a greater amount of Na,K‐ATPase molecules, estimated from anthroyl ouabain binding, than normotensive individuals. Both the microsomal fraction of placental cells and purified Na,K‐ATPase showed an increased affinity for the specific inhibitor ouabain which, in the case of the microsomes, bound with a dissociation constant of 0.9 nM as compared with 3.4 nM in the controls. Likewise, the dissociation constant of the ouabain complex with purified Na,K‐ATPase was about 3.5 times lower in the hypertensive patients. The differences are apparently caused by a different microenvironment of the ouabain‐binding site, as reflected in the quantum yield of bound anthroyl ouabain. If an endogenous digitalis‐like factor is present in the body fluids to regulate Na,K‐ATPase activity, the present results render its role quite plausible.
Both glucose‐type monosaccharides and one of their metabolites are required for activation of yeast plasma membrane H+‐ATPase.
Authors: Kotyk Arnost , Georghiou Georghios
Published: October 2002

Saccharomyces cerevisiae and Schizosaccharomyces pombe cells were grown on D‐glucose, D‐galactose, D‐fructose, D‐mannose, maltose, trehalose and ethanol. All these substrates were separately added to cells thus grown and the onset and rate of acidification mediated by the plasma membrane H+‐ATPase were determined. Irrespective of the growth substrate, the best triggers of acidification in both species were fructose, mannose and glucose (with average rates of 5.2, 5.0 and 4.8 nmol H+ per min per mg dry weight, respectively, for S. cerevisiae, and 4.5, 6.8 and 5.8 for S. pombe). These were followed in S. cerevisiae by galactose in Gal‐, Man‐ and Tre‐grown cells (about 0.40 nmol H+) and by maltose in Mal‐ and Tre‐grown cells (about 0.15 nmol H+). Trehalose elicited some response in only ethanol‐grown cells while ethanol itself was completely ineffective in activating the H+‐ATPase. In S. pombe, however, maltose caused an acidification rate of 3.6 nmol H+ per min per mg dry wt., followed by EtOH (().38), Gal (0.13) and Tre (0.05). 6‐Deoxy‐D‐glucose and 2‐deoxy‐D‐glucose, not metabolized or improperly metabolized analogues of glucose, had no effect whatsoever. ‐ It appears that the sensor triggering the ATPase‐activating pathway is a complex responding both to a glucose‐type sugar (Glc, Man, Fru) and possibly identical with one of the glucose carriers, and to one of its metabolites, most probably fructose‐6‐phosphate.
Is the recovery of microtubule orientation in pea roots dependent on the cell wall?
Authors: Holdaway N. J. , White R. G. , Overall R. L.
Published: October 2002

This study tested several aspects of a model proposed by Williamson (1990, 1991) in which stresses in plant cell walls, detected by stress‐receptive portions of inelastic cellulose microfibrils, orient microtubules via interactions with cell wall‐linked transmembrane proteins. Young expanding cells of pea root tips have highly ordered transverse arrays of microtubules oriented perpendicular to the direction of cell expansion. The recovery of these ordered MT arrays after depolymerisation with oryzalin was assessed. It was shown that treating roots with disruptors of microfibril synthesis (2,6‐dichlorobenzonitrile and calcofluor white) or the disruption of Arg‐Gly‐Asp (RGD)‐mediated wall‐membrane links did not affect the orientation of recovering microtubule arrays. Furthermore, cell wall stresses themselves appeared unnecessary for regeneration of transverse arrays. The relevance of these findings to Williamson's hypothesis is discussed.
Cytokeratin expression in human respiratory epithelium of nasal polyps and turbinates
Authors: Hicks Wesley , Ward Robert , Edelstein David , Hall Leon , Albino Anthony , Hard Robert , Asch Bonnie
Published: October 2002

The cytokertatins in respiratory epithelial cells (REC) of human nasal polyps and turbinates were analyzed by immunohistochemistry. Cytokeratin 19 (CK19) was present in all REC, CK5 and 14 were expressed primarily in basal cells, and CK7, 8, and 18 were found in suprabasal cells. Differences in cytoplasmic locations were also apparent among the individual cytokeratins. CK13 was not detected in any REC of these tissues. The results indicate the profile of cytokeratins in REC of human nasal polyps and turbinates is essentially identical to that of REC in the more distal respiratory tract.
OSTEOBLASTIC CELLS FROM RAT LONG BONE II: ADHESION TO SUBSTRATA AND INTEGRIN EXPRESSION IN PRIMARY AND PROPAGATED CULTURES
Authors: CASTOLDI MIRCO , PISTONE MARIO , CARUSO CRISTINA , PUDDU ALESSANDRA , FILANTI CRISTINA , PICCINI DANIELE , TACCHETTI CARLO , MANDUCA PAOLA
Published: October 2002

Propagation in vitro of rat tibial osteoblasts (ROB) is accompanied by increased expression of the early osteogenic marker alkaline phosphatase (AP) and maturation of the osteogenic phenotype. In order to establish the pattern of the integrin expressed in ROB during progression to the mature osteoblastic phenotype, we have used biosynthetic, immunoblotting and immuno‐histochemical assays. We immunoprecipitated from osteoblasts, expanded for 1.5‐ and 7.5‐doubling, α5β1, αvβ3, α3β1, α6β1 and α1β1 integrin heterodimers; furthermore β5, α2 and α4 chains were detected by immunoblots and indirect immunofluorescence. αv, α1, α6 subunits in most cells, and β3 and β1 subunits in a minority, were found to be associated with adhesion plaques in osteoblasts of 1.5‐, 4.5‐ and 7.5‐doubling grown in the presence of FCS, while all other subunits stained diffusely all the cells. Adhesion to fibronectin (FN), laminin (LN), collagen type I (COL I) and III (COL III) by ROB at different doubling (1.5–11) was dependent on substratum concentration, and after 2.5h at 55nm 60% of the cells adhered to all substrata. Arg‐Gly‐Asp‐Ser (RGDS) containing peptides inhibited adhesion of cells differentially, according to substratum; no dependence on extent of progation in vitro was observed. In conclusion, ROB cultured in vitro for 1.5‐ to 11‐doubling had an unchanged pattern of expression of integrin subunits, heterodimer association and cellular distribution. Adhesion specificity and affinity were also unchanged. These results suggest that the phenotypic maturation, detected as an increase in AP expression, is not accompanied by major changes in the potential for cell—matrix interactions, and does not correspond to changes in the type of integrin subunits expressed by osteoblasts.
KINESIN‐ASSOCIATED TRANSPORT IS INVOLVED IN THE REGULATION OF CELL ADHESION
Authors: KAVERINA IRINA N. , MININ ALEXANDER A. , GYOEVA FATIMA K. , VASILIEV JURY M.
Published: October 2002

It has been recently shown that depolymerization of microtubules induces the elongation of focal contacts at the leading edge. On the other hand, cell shape and pseudopodial activity were found to depend on the microtubule‐based motor kinesin. In this paper, we examine whether kinesin is involved in controlling the dynamics of adhesive structures at the cell surface. Microinjection of an antiblocking kinesin activityin vitrocauses focal contact elongation similar to the effect of microtubule‐depolymerizing drugs. Thus, the role of microtubules in cell adhesion lies in the supporting kinesin‐based transport to the adhesion sites.
E‐CADHERIN EXPRESSION CAN ALTER THE SPECIFICITY OF GAP JUNCTION FORMATION
Authors: PROWSE DAVID M. , CADWALLADER G. P. , PITTS J. D.
Published: October 2002

Specificity of gap junction formation produces communication compartments, groups of cells joined to each other by gap junctions (homologous communication) but more rarely to cells in adjacent compartments (heterologous communication). Specificity of junction formation can be studied in mixed cultures of different cell types. In these model systems, compartmentation is often associated with sorting out, a process that produces separate domains of the different cells. The borders of the physically distinct domains correlate with the functional boundaries of the communication compartments. Compartments have also been observedin vivowhere they are believed to play a role in separating groups of cells following different differentiation pathways. Two classes of cell surface molecule, connexins and cell adhesion molecules, are candidates for a role in the control of specificity. A representative of each class appears to be necessary for gap junction formation and both are expressed in a tissue specific manner. We have shown that mixed cultures of rat epithelial (BRL) cells and rat (BICR) fibroblasts show specificity, form communication compartments and sort out. Both cell types express the same connexin (connexin 43) but different cell adhesion molecules (BRL, P‐cadherin and 125‐kDa N‐cadherin; BICR, 140‐kDa N‐cadherin). Transfection of both cell types with E‐cadherin results in a 10‐fold increase in heterologous communication. These data suggest that E‐cadherin plays a role in the control of specificity of gap junction formation.
TYROSINE KINASE INHIBITORS REVERSE BUTYRATE STIMULATION OF HUMAN CACO‐2 INTESTINAL EPITHELIAL CELL ALKALINE PHOSPHATASE BUT NOT BUTYRATE PROMOTION OF DIPEPTIDYL DIPEPTIDASE
Authors: BASSON MARC D. , HONG FU
Published: October 2002

Short chain fatty acids such as sodium butyrate are concentrated in the colonic lumen and may protect against colon carcinogenesis by maintaining colonocytic differentiation, but the mechanisms by which they act are not fully understood. It has recently been suggested that short chain fatty acids modulate cellular tyrosine kinase activity in addition to altering chromatin structure via regulation of histone acetylation and DNA methylation. Therefore, the authors evaluated the influence of tyrosine kinase inhibition on the effects of 10mM butyrate on human Caco‐2 intestinal epithelial differentiation, using alkaline phosphatase and dipeptidyl dipeptidase specific activity as markers of differentiation, and two tyrosine kinase inhibitors, of different mechanisms of action and different effects on Caco‐2 brush border enzyme specific activity, to block tyrosine kinase activity. As expected, butyrate stimulated both alkaline phosphatase and dipeptidyl dipeptidase specific activity. The tyrosine kinase inhibitors prevented, and indeed one inhibitor reversed the effects of butyrate on alkaline phosphatase specific activity. However, tyrosine kinase inhibition did not prevent butyrate stimulation of dipeptidyl dipeptidase specific activity. Different pathways are likely to regulate the effects of butyrate on expression of these two brush border enzymes. Butyrate stimulation of alkaline phosphatase, but not dipeptidyl dipeptidase, may involve tyrosine phosphorylation signaling.
THIAZOLIDINEDIONE INDUCES THE ADIPOSE DIFFERENTIATION OF FIBROBLAST‐LIKE CELLS RESIDENT WITHIN BOVINE SKELETAL MUSCLE
Authors: TORII SHIN‐ICHIRO , KAWADA TERUO , MATSUDA KYOKO , MATSUI TOHRU , ISHIHARA TOMOMI , YANO HIDEO
Published: October 2002

To investigate the role of peroxisome proliferator‐activated receptor γ (PPARγ) in adipocyte formation within the skeletal muscle of beef cattle, fibroblast‐like cells were isolated from the longissimus muscle of cattle and cultured with activators of murine PPARγA thiazolidinedione T‐174, which is a specific ligand for PPARγ, stimulated adipose differentiation (evaluated by counting differentiated adipocytes under microscopic observation) in a dose‐dependent fashion. A peroxisome proliferator Wy14,643 which strongly activates the α isoform of murine PPAR also stimulated differentiation but its potency was weaker than that of T‐174. Unexpectedly, 15‐deoxy‐Δ12,14‐prostaglandin J2, which is believed to be an endogenous ligand for PPARγ, could not induce adipose differentiation in doses which have been found to be effective on rodent cells. Immunoblotting analysis confirmed the significant expression of PPARγ protein in fibroblast‐like cell cultures prepared from bovine skeletal muscle. In conclusion, bovine skeletal muscle contains adipose precursor cells expressing functionally active PPARγ.
GROWTH OF MDA‐MB‐231 CELL LINE: DIFFERENT EFFECTS OF TGF‐β1, EGF AND ESTRADIOL DEPENDING ON THE LENGTH OF EXPOSURE
Authors: Mur Cristina , Martínez‐Carpio Pere A. , Fernández‐Montolí María E. , Ramon Josep M. , Rosel Pilar , Navarro Miguel A.
Published: October 2002

The human cell line MDA‐MB‐231 is a prototype for the study of hormone‐independent breast cancer. Modification of cell growth behaviour has been observed after treating these cells with growth factors. EGF is a typical stimulatory growth factor for many cell types, whereas transforming growth factor β1(TGF‐β1) acts with inhibitory character. Here we observed cell growth inhibition after EGF as well as after TGF‐β1treatments. Nevertheless, in the 42‐h experiments, EGF‐treated cultures grew before (18 hours) respect to the TGF‐β1and E2‐treated cultures (24h), and in the 11‐day experiments, EGF‐treated cultures started growing (7 days) after TGF‐β1‐treated cultures (5 days). Estradiol inhibited the proliferation of these cells only after several days of treatment.
EFFECTS OF COLD ACCLIMATION ON THE ACTIVITY LEVELS OF CREATINE KINASE, LACTATE DEHYDROGENASE AND LACTATE DEHYDROGENASE ISOENZYMES IN VARIOUS TISSUES OF THE RAT
Authors: Terblanche S. E. , Masondo T. C. , Nel W.
Published: October 2002

The effects of cold acclimation on the activity levels of creatine kinase, lactate dehydrogenase and lactate dehydrogenase isoenzymes in various tissues/ organs of the rat (Rattus norvegicus) were investigated. Male Sprague‐Dawley rats were divided into two groups. One group was housed at 4±1°C (experimental group) and the other at 24±1°C (control group) for six months. The rats were housed in single cages and had access to food and water ad libitum. The tissues/organs investigated were heart, liver, lung, kidney, gastrocnemius muscle and interscapular brown adipose tissue as well as serum. With the exception of lung, (which showed a decrease of 24%) total creatine kinase activity levels were significantly increased (P< 0.05) in all the tissues/organs investigated (17–51%) as well as serum (34%), in cold acclimated animals. Cold acclimation also resulted in significantly increased (P< 0.05) activity levels of lactate dehydrogenase in all the tissues/organs investigated (14–24%) as well as serum (35%). Cold exposure resulted in an increase of the activity levels of all the detectable isoenzymes of lactate dehydrogenase, although not always significant, in all the tissues/organs investigated as well as serum. The M4tetramer of lactate dehydrogenase was the only detectable isoenzyme in serum.
S ‐ADENOSYLMETHIONINE SYNTHESIS IN LEISHMANIA INFANTUM PROMASTIGOTES
Authors: Reguera R. M. , Pérez‐Pertejo Y. , Ordóñez C. , Cubría J. C. , Tekwani B. L. , Balaña‐Fouce R. , Ordóñez D.
Published: October 2002

Methionine adenosyltransferase (MAT), S ‐adenosylmethionine (AdoMet), and S ‐adenosylhomocysteine (AdoHcy), have been analysed at different time‐points during the growth curve of Leishmania infantum. MAT activity and AdoMet content peaked in the lag and early log phases, whereas higher levels of AdoHcy were found in stationary phase cells. MAT activity of cell extracts displayed hyperbolic kinetics for both its substrates, l ‐methionine and ATP, with km values of 35μm and 5m m, respectively. MAT has an absolute requirement for divalent cations, and is dependent on sulfydryl protective agents. Unlike other sources, L. infantum MAT activity seems to be transcriptionally regulated, with an accumulation of MAT‐mRNA during rapid growth periods of promastigotes.
CYTOTOXICITY BY STORED HUMAN BREAST‐MILK: POSSIBLE CONTRIBUTION OF COMPLEMENT SYSTEM
Authors: Ogundele Michael Oladipo
Published: October 2002

Human milk stored over some period in vitro possesses certain cytotoxic properties, which require further studies. Cytolysis induced by stored human milk has now been further characterized, using rabbit red blood cells as targets, to determine the contribution of other components, particularly the complement system. Cytolysis was found to be temperature dependent, greatly enhanced by low concentrations of magnesium and calcium ions, but inhibited by moderate to excessive amounts of calcium ions, and by heating at 56°C.
ROLE OF TGF‐β IN THE RETINOIC ACID‐INDUCED INHIBITION OF PROLIFERATION AND MELANIN SYNTHESIS IN CHICK RETINAL PIGMENT EPITHELIAL CELLS IN VITRO
Authors: Kishi Hiroko , Kuroda Etsushi , Mishima Hiromu K. , Yamashita Uki
Published: October 2002

The purpose of this study was to investigate the effects of all‐trans retinoic acid (RA) on the induction of transforming growth factor‐β (TGF‐β) that is concerned with the proliferation and melanin synthesis of chick retinal pigment epithelial (RPE) cells in vitro. Chick RPE cells were cultured in the presence or absence of RA and anti‐TGF‐β antibody for 7 days. The effects of RA and pan‐specific TGF‐β antibody on RPE cell proliferation were assessed by counting the number of cells, and their effects on melanin synthesis were evaluated by measuring the melanin content of the cells. TGF‐β activity in the culture supernatant of RPE cells was measured using CCL‐64 cells. RA significantly inhibited RPE cell proliferation and increased melanin synthesis. The addition of pan‐specific TGF‐β antibody to the culture blocked the inhibition of RPE cell proliferation and the increased melanin synthesis. RA induced TGF‐β production in the culture supernatant of RPE cells. These findings indicate that RA regulates the proliferation and melanin synthesis of RPE cells via induction of TGF‐β.
CHARACTERIZATION OF PROTEINS ASSOCIATED WITH HEAT SHOCK PROTEIN HSP27 IN THE SQUAMOUS CELL CARCINOMA CELL LINE A431
Authors: Kindas‐Mügge Ingela , Riedler Constanze , Fröhlich Ilse , Micksche Michael , Trautinger Franz
Published: October 2002

Heat shock protein hsp27 is a molecular chaperone and identification of hsp27‐binding proteins might help to elucidate its functional role in keratinocyte biology. In the present investigation we used a human epidermal cell carcinoma cell line (A431) transfected with hsp27 (A431/16) to study interference between hsp27 protein and other proteins. Immunoprecipitation experiments with anti‐hsp27 antibody revealed a multicomponent complex when analysed by silver staining. By immunoblotting analysis we could demonstrate that hsp27 associates with actin, the mutant form of p53, hsp70 and hsp90. Immunofluorescence analysis showed a co‐localization between hsp27 and p53, hsp70 and hsp90. To control for the specificity of the observed interactions, immuno‐precipitations with antibodies to actin, p53, hsp70 and hsp90 respectively, were performed. All of the tested proteins demonstrated a coimmunoprecipitation with hsp27. We conclude that hsp27, like the other heat shock proteins, is part of a complex system of molecular chaperones in epidermal keratinocytes.
MODULATION OF C‐ MYC AND C‐ FOS GENE EXPRESSION IN REGENERATING RAT LIVER BY 2‐MERCAPTOPROPIONYLGLYCINE
Authors: Ohri Sujata , Sharma Dipali , Dixit Aparna
Published: October 2002

Expression of the two proto‐oncogenes, c‐ myc and c‐ fos, in proliferating liver, and the modulation of their expression by 2‐mercaptopropionylglycine (MPG) has been investigated. A significant increase in the expression of both c‐ myc and c‐ fos was observed, attaining a peak at 30min, followed by a gradual decline for 8h after partial hepatectomy. Treatment of partially hepatectomized animals with MPG resulted in a significant decrease in the expression of both genes, the decrease being more marked in c‐ myc mRNA levels. At later time points, there was a very small rise in the mRNA levels of these genes in MPG‐treated animals but they still remained much lower than the peak levels observed in both genes 30min after surgery. A decline in the recovery of liver weight in MPG‐treated animals was also observed.
EFFECTS OF 3‐D CLINO‐ROTATION ON GENE EXPRESSION IN HUMAN FIBROBLAST CELLS
Authors: Arase Yoshiko , Nomura Jun , Sugaya Shigeru , Sugita Katsuo , Kita Kazuko , Suzuki Nobuo
Published: October 2002

Continuous variation in the direction of the gravity vector leads to various cellular responses including modulation of gene expression. Complementary DNA (cDNA) array analyses are available to observe the variation of gene expression under different conditions. In this study, expression levels of 588 representative genes were compared using the Atlas™ human cDNA expression array in human fibroblast cells with and without 3‐dimensional (3‐D) clinostat. Five upregulated and 8 downregulated genes were detected. Among these genes, upregulation of XRCC1, and downregulation of ERB‐B2 and p21Cip1/Waf1 were confirmed by RT‐PCR. These results suggested that the gene expression levels ofXRCC1, ERB‐B2 and p21Cip1/Waf1 were modulated by vector‐averaged microgravity induced by 3‐D clinostat in human fibroblast cells. Our findings may be a basis for the biological study of 3‐D culture systems.
MORPHOLOGICAL CHARACTERIZATION OF CELL DEATH DURING THE OVARY DIFFERENTIATION IN WORKER HONEY BEE
Authors: Reginato Rejane Daniele , Da Cruz‐Landim Carminda
Published: October 2002

Cell death that occurs during ovary differentiation in the honeybee worker's larval development accounts for ovariole reabsorption. From a morphological standpoint, three modes of death were detected. Germinative cells in the ovarioles die by an apoptotic‐like process, whereas the somatic cells die by an autophagic process, type II cell death; and during pupation, stromatic and ovarian capsular cells die through cytoplasmic disintegration, releasing their components into the hemolymph. These modes of cell death are in part determined by the pattern of tissue organization within which the cell occurs.
GAP JUNCTION INTERCELLULAR COMMUNICATION DURING LYMPHOCYTE TRANSENDOTHELIAL MIGRATION
Authors: Oviedo‐Orta Ernesto , Errington Rachel J. , Evans W. Howard
Published: October 2002

Migration of lymphocytes across the endothelium of central or peripheral tissues, a process occurring following activation or differentiation, involves cell to cell interactions featuring adhesion and heterotypic signalling ‘cross‐talk’. Since lymphocytes and endothelial cells express connexins, the subunit proteins of gap junction intercellular channels, we investigated whether these channels feature in heterotypic signalling during transendothelial migration of lymphocytes. We show, using FACS analysis, that calcein, a gap junction permeant fluorescent dye, was transferred from endothelial cell layers to lymphocytes. The gap junction involvement in intercellular dye transfer was reinforced by studies showing that the process was inhibited by connexin mimetic peptides, a new class of reagents shown to block gap junction communication. Further evidence for the involvement of lymphocyte gap junctions in intercellular communication during transendothelial migration was obtained by two‐photon laser scanning microscopy. Although gap junctional communication was inhibited by connexin mimetic peptides, they had little influence on the transmigration process.
ENHANCEMENT OF IMMUNOGOLD‐LABELLED FOCAL ADHESION SITES IN FIBROBLASTS CULTURED ON METAL SUBSTRATES: PROBLEMS AND SOLUTIONS
Authors: Owen G. Rh. , Meredith D. O. , Gwynn Ap I. , Richards R. G.
Published: October 2002

Visualisation of cell adhesion patterns by scanning electron microscopy requires special preparation and labelling. The membranes and cytoplasm must be removed, without damaging the antigen, to facilitate antibody access to vinculin in the focal adhesions. Low beam energy imaging is used to visualise the cell undersurface (embedded in resin after staining with osmium tetroxide) and immunogold‐labelled adhesion sites. The gold probe, must be large enough (>40nm) for detection, while viewing the whole cell, but large gold markers increase steric hindrance and decrease labelling efficiency. This problem can be overcome by using small gold probes (1–5nm) followed by enlargement with silver enhancement, but osmium tetroxide stain etches the silver. We demonstrated that metal substrates increased this etching. Reducing the concentration of osmium tetroxide and incubation time reduced the amount of etching. We have demonstrated that gold enhancement was not etched by osmium tetroxide, irrespective of the substrate. Therefore, comparative studies of cell adhesion to different biomaterial substrates can be performed using immunogold‐labelling with gold enhancement.
IN VITRO BEHAVIOUR OF HUMAN OSTEOBLASTS ON DENTIN AND BONE
Authors: Scheven B. A. A. , Marshall D. , Aspden R. M.
Published: October 2002

This investigation studied how the behaviour of isolated osteoblasts on standard tissue culture polystyrene compared with cells cultured on cut surfaces of dentin, a natural calcified material. Cellular attachment, viability and growth were monitored in parallel cultures of human osteosarcoma cell lines (MG63, HOS TE85, SaOS‐2) and primary human osteoblast‐like cells (HOBs). Culture plastic was either left untreated or roughened with abrasive paper of various grit sizes (4000–1200 grit) in order to obtain a level of roughness comparable to that of the dentin slices. Cell counting and intracellular BCECF staining showed that after an initial incubation of 2h, the primary cells attached and spread out more quickly on the different substrates than the three cell lines. The primary cells also showed a stronger mitochondrial staining and viability on dentin. During subsequent culture morphological differences appeared with the cells on dentin displaying more cellular extensions. All three cell lines proliferated more slowly on dentin than on plastic. In contrast, the primary HOBs were not significantly affected in their growth by the different substrates. Total and specific alkaline phosphatase (AP) activity of the cell lines was not significantly affected by the different substrates after short‐term adhesion, but it was increased for the primary cells on the dentin. However, after 2–3 days of culture, AP was decreased on the dentin slices for both the cell lines and primary HOBs. Plasma treatment of the roughened plastic did not alter cellular viability or AP activity, suggesting that grinding of the surface did not affect the property of the culture plastic to support cell attachment and growth. In conclusion, the results show that not only do osteoblastic cells behave differently on a natural calcified substrate surface than on standard culture plastic, but also that differences were evident between the various cell types, in particular the primary HOBversus the continuous cell lines.
SULPHATE INFLUX IN THE ERYTHROCYTES OF NORMOTENSIVE, DIABETIC AND HYPERTENSIVE PATIENTS
Authors: Romano L. , Scuteri A. , Gugliotta T. , Romano P. , De Luca G. , Sidoti A. , Amato A.
Published: October 2002

This study aimed to show that modifications in intracellular metabolism are implicated in the pathophysiology of diabetes mellitus and essential hypertension. In fact, total magnesium, calcium, sodium and potassium concentrations, measured in the erythrocytes of normotensive, diabetic and hypertensive patients, have given the following results: a lower intracellular potassium concentration in the erythrocytes of diabetic and hypertensive patients than the erythrocytes of normotensive patients and a more elevated sodium, magnesium, calcium concentrations in the erythrocytes of diabetic and hypertensive patients than the normotensive.

Because of the importance of Mg2+ and Ca2+ in metabolic enzyme regulation and their interaction with both Hb and band 3 protein, we examined SO2−4 kinetic influx in the erythrocytes of normotensive, hypertensive and diabetic patients. The kinetic plots showed different profiles over the three groups and the fluxes were found to be 0.024, 0.061 and 0.072mmol×(l cells×min)−1 in normotensive, hypertensive and diabetic patients, respectively. We also found that the Vmax and Km of sulphate influx, obtained by Hofstee plots, increased in the erythrocytes of hypertensive and diabetic patients compared with control cells. In contrast, sulphate influx in the erythrocytes of diabetic and hypertensive patients in the presence of Nifedipine, a calcium antagonist, showed no difference either in the rate constants or in the kinetic profiles, compared to the normotensive control subjects.