bluuebunny/crossref_metadata_2025 huggingface dataset:
Biodegradable dextran–polylactide hydrogel networks: Their swelling, morphology and the controlled release of indomethacin
Authors: Zhang Yeli , Chu Chih‐Chang
Published: August 2002

Biodegradable polymer hydrogel networks based on hydrophilic dextran derivative of allyl isocyanate (dex‐AI) and hydrophobic poly (D,L) lactide diacrylate macromer (PDLLAM) were synthesized, and their swelling and morphological properties were studied. During a 2‐day incubation, the higher the PDLLAM composition in the hydrogel, the slower the swelling as well as the lower the extent of swelling were. A 3D porous network structure was observed by scanning electron microscope. The rate of formation of this 3D porous network structure depended on the hydrophilicity of the components, their composition ratio, and the degradation time. The highly hydrophilic dex‐AI component facilitated the formation of this 3D porous network structure at an earlier immersion period, while the degradability of the PDLLAM component would make this 3D porous network structure more open at a later immersion period. Indomethacin, a low molecular weight and moderately hydrophobic drug, was incorporated into the hydrogels for the release study in pH 7.4 phosphate buffer solution at 37 °C. The release kinetics suggested, as the PDLLAM composition increased, the indomethacin diffusion coefficient (D) and release half life time (t1/2) decreased, while the release index n increased. The controlled release mechanism was determined by the combination of three factors: the rate and degree of formation of swelling‐induced 3D porous structure in the hydrogel, the hydrolytic degradation of PDLLAM components, and the hydrophobic interaction between PDLLAM and IDM. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 318–328, 2002
Matrix engineering for osteogenic differentiation of rabbit periosteal cells using α‐tricalcium phosphate particles in a three‐dimensional fibrin culture
Authors: Spitzer Ron‐Sascha , Perka Carsten , Lindenhayn Klaus , Zippel Hartmut
Published: August 2002

Tissue engineering using periosteal cells is a promising approach for bioactive bone repair. Of central importance in tissue engineering is the cell–matrix interaction. In the present study we tested in vitro the influence of α‐tricalcium phosphate (α‐TCP) particles on the expression of osteogenic markers in rabbit periosteal cells embedded in specially manufactured fibrin beads. After cell isolation from tibial periosteum of New Zealand White rabbits, and following monolayer culture, cells were embedded in alginate–fibrin beads containing 7.5% α‐TCP particles and, as a control group, in beads without particles. The alginate was extracted immediately after polymerization. The beads were cultivated for at least 53 days. The DNA content, alkaline phosphatase activity, and osteocalcin level were determined. In monolayer culture the number of cells increased 6.5‐fold. DNA content increased in both three‐dimensional culture groups but was significantly higher in the beads containing α‐TCP. Alkaline phosphatase activity increased in both groups without significant differences. Osteocalcin content was significantly higher in the beads containing α‐TCP than it was in those without α‐TCP. These observations indicate that matrix engineering using inorganic particles in fibrin culture can influence the osteogenic differentiation of mesenchymal cells. The three‐dimensional culture system presented here facilitates the preparation of grafts for bone reconstruction. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 690–696, 2002
High stability binding of poly(ADPribose) polymerase‐like thermozyme from S. solfataricus with circular DNA
Authors: Faraone‐Mennella Maria Rosaria , De Luca Paola , Giordano Anna , Gambacorta Agata , Nicolaus Barbara , Farina Benedetta
Published: August 2002

The poly(ADPribose) polymerase‐like thermozyme from the hyperthermophilic archaeon S. solfataricus was found to bind DNA with high affinity and non‐specifically. Binding was independent of base composition and length of the nucleic acid, and the protein showed a slight preference for the circular structure. By using pCMV‐Neo‐Bam plasmid as experimental model, the behaviour of the thermozyme upon binding with either circular or linear plasmid was analyzed. pCMV‐Neo‐Bam has a single HindIII site that allows to obtain the linear structure after digestion with the restriction enzyme. Intrinsic tryptophan‐dependent fluorescence of poly(ADPribose) polymerase‐like thermozyme noticeably changed upon addition of either circular or linear plasmid, showing the same binding affinity (K = 2 × 109 M−1). However, experiments of protection against temperature and DNase I gave evidence that the thermozyme formed more stable complexes with the circular structure than with the linear pCMV‐Neo‐Bam. Increasing temperature at various DNA/protein ratios had a double effect to reduce the amount of circular DNA undergoing denaturation and to split the melting point towards higher temperatures. Nil or irrelevant effect was observed with the linear form. Similarly, DNase acted preferentially on the linear plasmid/protein complexes, producing an extensive digestion even at high protein/DNA ratios, whereas the circular plasmid was protected by the thermozyme in a dose‐dependent manner. The complexes formed by archaeal poly(ADPribose) polymerase (PARPss) with the circular plasmid were visualized by bandshift experiments both with ethidium bromide staining and by labelling the circular plasmid with 32P. The stability of complexes was tested as a function of enzyme concentration and in the presence of a cold competitor and of 0.1% SDS. From the performed experiments, a number of 3–10 base pairs bound per molecule of enzyme was calculated, indicating a high frequency of binding. The presence of circular DNA was also able to increase by 80% the poly(ADPribose)polymerase‐like activity, as compared to 25% activation induced by the linear pCMV‐Neo‐Bam. J. Cell. Biochem. 85: 158–166, 2002. © 2002 Wiley‐Liss, Inc.
Phenotypic effects of continuous or discontinuous treatment with dexamethasone and/or calcitriol on osteoblasts differentiated from rat bone marrow stromal cells
Authors: Atmani Hassan , Audrain Christine , Mercier Louis , Chappard Daniel , Basle Michel F.
Published: August 2002

Osteoblasts are target cells for glucocorticoids and calcitriol, and their phenotype is greatly modified by these hormones. We investigated the effect of continuous or discontinuous hormonal exposure to osteoblasts derived from rat bone marrow stromal cells in long‐term subcultures. Stromal cells were grown in primoculture in presence of dexamethasone (dex), but in following subcultures, dex and/or calcitriol were added just after seeding or after a 7‐day hormone‐free period. Cell proliferation, alkaline phosphatase (ALP) histochemical staining, and enzymatic bioactivity measurement, osteocalcin (OC), ALP and bone sialoprotein (BSP) mRNA expression were used to study the differential effect on osteoblastic phenotype of various conditions of treatment by dex and calcitriol. In primoculture, the osteoblastic differentiation was confirmed by the formation of calcified nodules and by strong expression of ALP, OC, and BSP mRNAs. In subcultures, proliferation of stromal cells was stimulated by dex and inhibited by calcitriol and by both hormones. Cell proliferation was not modified by hormonal lack during 7 days. Continuous hormonal treatment by dex strongly enhanced OC and BSP mRNAs, but apparently did not modified ALP mRNAs expression. Continuous treatment by calcitriol decreased ALP and the dex‐induced BSP expression and stimulated the OC mRNAs level, strongly when associated with dex. The population of ALP+ cells and ALP bioactivity were strongly increased by dex, whereas calcitriol or both hormones decreased them. When the subcultures were undergone without hormonal treatment during 7 days, all osteogenic mRNAs strongly decreased even after hormonal recovery. Dex, calcitriol, and both hormones inhibited ALP mRNAs. OC messengers were only weakly detectable with both hormones. ALP+ cell population and ALP bioactivity were decreased after 14 days of hormonal treatment recovery. These results support that continuous presence of glucocorticoids appears as a major key for the permanent expression of the osteoblastic phenotype that is inhibited by calcitriol, in the rat bone marrow. J. Cell. Biochem. 85: 640–650, 2002. © 2002 Wiley‐Liss, Inc.
Expression and function of CCAAT/enhancer binding proteinβ (C/EBPβ) LAP and LIP isoforms in mouse mammary gland, tumors and cultured mammary epithelial cells
Authors: Dearth L.R. , Hutt J. , Sattler A. , Gigliotti A. , DeWille J.
Published: August 2002

CCAAT/Enhancer binding proteins (C/EBPs) play important roles in the regulation of cell growth and differentiation. This study investigated the expression and function of C/EBPβ isoforms in the mouse mammary gland, mammary tumors, and a nontransformed mouse mammary epithelial cell line (HC11). C/EBPβ mRNA levels are 2–5‐fold higher in mouse mammary tumors derived from MMTV/c‐neu transgenic mice compared with lactating and involuting mouse mammary gland. The “full‐length” 38 kd C/EBPβ LAP (“Liver‐enriched Activator Protein”) isoform is the predominant C/EBPβ protein isoform in mammary tumor whole cell lysates, however, the truncated 20 kd C/EBPβ LIP (“Liver‐enriched Inhibitory Protein”) isoform is also present at detectable levels (mean LAP:LIP ratio 5.3:1). The mammary tumor C/EBPβ LAP:LIP ratio decreases 70% (from 5.3:1 to 1.6:1) when lysate preparation is switched from a rapid whole cell lysis protocol to a multistep nuclear/cytoplasmic fractionation protocol. In contrast to mammary tumors, only the C/EBPβ LAP isoform is detectable in the mammary gland whole cell and nuclear lysates; the truncated “LIP” isoform is undetectable regardless of isolation protocol. Ectopic over expression of C/EBPβ LIP or C/EBPβ LAP did not alter HC11 growth rates. However, C/EBPβ LIP over expressing HC11 cells (LAP:LIP ratio of ∼1:1) exhibited a consistent 2–4 h delay in G0/S phase transition. C/EBPβ LIP overexpressing HC11 cells did not express β‐casein mRNA (mammary epithelial cell differentiation marker) in response to lactogenic hormones. This defect in β‐casein expression was not corrected by carrying out the differentiation protocol in the presence of an artificial extracellular matrix. These results demonstrate that the “full‐length” C/EBPβ LAP isoform is the predominant C/EBPβ protein isoform expressed in mouse mammary gland in vivo and mouse mammary epithelial cell cultures in vitro. C/EBPβ LIP detected in mammary tumor lysates may result from in vivo production or ex vivo isolation‐induced proteolysis of C/EBPβ LAP. Ectopic overexpression of C/EBPβ LIP (LAP:LIP ratio of ∼1:1) inhibits mammary epithelial cell differentiation (β‐casein expression). J. Cell. Biochem. 82:357–370, 2001. © 2001 Wiley‐Liss, Inc.
Upregulation of the gene encoding a cytoplasmic dynein intermediate chain in senescent human cells
Authors: Horikawa Izumi , Parker Elaine S. , Solomon Gregory G. , Barrett J. Carl
Published: August 2002

Normal human somatic cells, unlike cancer cells, stop dividing after a limited number of cell divisions through the process termed cellular senescence or replicative senescence, which functions as a tumor‐suppressive mechanism and may be related to organismal aging. By means of the cDNA subtractive hybridization, we identified eight genes upregulated during normal chromosome 3‐induced cellular senescence in a human renal cell carcinoma cell line. Among them is the DNCI1 gene encoding an intermediate chain 1 of the cytoplasmic dynein, a microtubule motor that plays a role in chromosome movement and organelle transport. The DNCI1 mRNA was also upregulated during in vitro aging of primary human fibroblasts. In contrast, other components of cytoplasmic dynein showed no significant change in mRNA expression during cellular aging. Cell growth arrest by serum starvation, contact inhibition, or γ‐irradiation did not induce the DNCI1 mRNA, suggesting its specific role in cellular senescence. The DNCI1 gene is on the long arm of chromosome 7 where tumor suppressor genes and a senescence‐inducing gene for a group of immortal cell lines (complementation group D) are mapped. This is the first report that links a component of molecular motor complex to cellular senescence, providing a new insight into molecular mechanisms of cellular senescence. J. Cell. Biochem. 82:415–421, 2001. © 2001 Wiley‐Liss, Inc.
Age‐related decline in the osteogenic potential of human bone marrow cells cultured in three‐dimensional collagen sponges
Authors: Mueller Stefan M. , Glowacki Julie
Published: August 2002

Studies with human and animal culture systems indicate that a sub‐population of bone marrow stromal cells has the potential to differentiate into osteoblasts. There are conflicting reports on the effects of age on human marrow‐derived osteogenic cells. In this study, we used a three dimensional (3D) culture system and quantitative RT‐PCR methods to test the hypothesis that the osteogenic potential of human bone marrow stromal cells decreases with age. Marrow was obtained from 39 men aged 37 to 86 years, during the course of total hip arthroplasty. Low‐density mononuclear cells were seeded onto 3D collagen sponges and cultured for 3 weeks. Histological sections of sponges were stained for alkaline phosphatase activity and were scored as positive or negative. In the group ≤ 50 years, 7 of 11 samples (63%) were positive, whereas only 5 of 19 (26%) of the samples in the group  ≥ 60 years were positive (p = 0.0504). As revealed by RT‐PCR, there was no expression of alkaline phosphatase or collagen type I mRNA before culture, however there were strong signals after 3 weeks, an indication of osteoblast differentiation in vitro. We performed a quantitative, competitive RT‐PCR assay with 8 samples (age range 38–80) and showed that the group ≤ 50 years had 3‐fold more mRNA for alkaline phosphatase than the group ≥ 60 years (p = 0.021). There was a significant decrease with age (r = − 0.78, p = 0.028). These molecular and histoenzymatic data indicate that the osteogenic potential of human bone marrow cells decreases with age. J. Cell. Biochem. 82: 583–590, 2001. © 2001 Wiley‐Liss, Inc.
Regulation of the subcellular distribution and gene expression of GABAA receptor by microtubules and microfilaments in cultured brain neurons
Authors: Ho Wen‐Hsin , Wang Seu‐Mei , Yin Hsiang‐Shu
Published: August 2002

Mechanisms underlying the intracellular transport of γ‐aminobutyric acidA receptor (GABAAR) were examined in the cultured neurons derived from chicken embryo brains. In situ trypsinization of the cultures and 3H‐flunitrazepam (FNZ) binding assay were employed to determine the cell surface and intracellular distribution of the receptor. A 3‐h treatment of the cells with 1 μM of colchicine, a microtubule depolymerizer, reversibly raised the proportion of intracellular GABAAR density by about 36% and decreased that of the cell surface receptors by 18% from respective control values, whereas the 3‐h incubation with 2 μM of cytochalasin D, a microfilament disrupter, did not cause significant changes. These treatments failed to alter the total number of the 3H‐FNZ binding sites of the neurons and the affinity of the ligand. Moreover, the exposure to colchicine seemed to produce a stronger cytoplasmic immunostaining of the GABAAR α subunits in many neurons without affecting the total cellular level of the proteins, in accordance with the increased fraction of intracellular 3H‐FNZ binding. However, in the neurons exposed to cytochalasin D, there was an increase of around 28% in the total content of α1+51kDa proteins. In addition, the colchicine or cytochalasin D treatment inhibited approximately 21 or 18% of the rate of general protein synthesis in the culture. Notably, in situ hybridization assay showed that the GABAAR α1 or α2 mRNA was present in 92 ± 2% or 94 ± 2% of the cytochalasin D‐treated neurons, both of which were higher than 71 ± 2–74 ± 3% of the control and colchicine‐treated cells. The data suggest that by regulating the intracellular transport, the microtubular system participates in the maintenance of normal subcellular distribution of GABAAR in the neurons. By contrast, the organization of microfilaments may play a role in modulating the gene expression of GABAAR subunits. J. Cell. Biochem. 83: 291–303, 2001. © 2001 Wiley‐Liss, Inc.
Salvia miltiorrhiza inhibits intimal hyperplasia and monocyte chemotactic protein‐1 expression after balloon injury in cholesterol‐fed rabbits
Authors: Chen Yuh‐Lien , Yang Sung‐Pao , Shiao Ming‐Shi , Chen Jaw‐Wen , Lin Shing‐Jong
Published: August 2002

Antioxidants that prevent low density lipoproteins (LDL) from oxidation may inhibit atherosclerosis and post‐angioplasty restenosis. Salvia miltiorrhiza (SM) has been shown to inhibit LDL oxidation and reduce atherosclerosis in cholesterol‐fed rabbits. The effects of SM on neointimal hyperplasia and monocyte chemotactic protein‐1 (MCP‐1) expression after balloon injury were studied. Male New Zealand white rabbits were fed a 2% cholesterol diet together with daily SM (4.8 gm/kg body wt.) treatment (SM; n=10) or without SM as a control (C; n=9) for 6 weeks. Probucol‐treated (0.6 gm/kg body wt.) rabbits (P; n=9) were used as a positive control group. A balloon injury of the abdominal aorta was performed at the end of the third week. Aortas were harvested at the end of 6 weeks. The plasma cholesterol levels were lowered in SM group. The neointimal hyperplasia in abdominal aortas was significantly inhibited in SM group [neointima/media area ratio: 0.63±0.05 (SM) versus 0.78±0.05 (C); P < 0.05] and in P group [0.45±0.02 (P) versus 0.78±0.05 (C); P < 0.05] when compared with C group. SM treatment significantly reduced MCP‐1 mRNA and protein expression in balloon‐injured abdominal aorta. These inhibitory effects on intimal response after balloon injury might be attributed to antioxidant capacity and cholesterol lowering effect of SM. SM treatment may offer some protection against post‐angioplasty restenosis. J. Cell. Biochem. 83: 484–493, 2001. © 2001 Wiley‐Liss, Inc.
Estrogen regulation of human osteoblast function is determined by the stage of differentiation and the estrogen receptor isoform
Authors: Waters Katrina M. , Rickard David J. , Riggs B. Lawrence , Khosla Sundeep , Katzenellenbogen John A. , Katzenellenbogen Benita S. , Moore John , Spelsberg Thomas C.
Published: August 2002

Although osteoblasts have been shown to respond to estrogens and express both isoforms of the estrogen receptor (ERα and ERβ), the role each isoform plays in osteoblast cell function and differentiation is unknown. The two ER isoforms are known to differentially regulate estrogen‐inducible promoter‐reporter gene constructs, but their individual effects on endogenous gene expression in osteoblasts have not been reported. We compared the effects of 17β‐estradiol (E) and tamoxifen (TAM) on gene expression and matrix formation during the differentiation of human osteoblast cell lines stably expressing either ERα (hFOB/ERα9) or ERβ (hFOB/ERβ6). Expression of the appropriate ER isoform in these cells was confirmed by northern and western blotting and the responses to E in the hFOB/ERβ6 line were abolished by an ERβ‐specific inhibitor. The data demonstrate that (1) in both the hFOB/ER cell lines, certain responses to E or TAM (including alkaline phosphatase, IL‐6 and IL‐11 production) are more pronounced at the late mineralization stage of differentiation compared to earlier stages, (2) E exerted a greater regulation of bone nodule formation and matrix protein/cytokine production in the ERα cells than in ERβ cells, and (3) the regulated expression of select genes differed between the ERα and ERβ cells. TAM had no effect on nodule formation in either cell line and was a less potent regulator of gene/protein expression than E. Thus, both the ER isoform and the stage of differentiation appear to influence the response of osteoblast cells to E and TAM. J. Cell. Biochem. 83: 448–462, 2001. © 2001 Wiley‐Liss, Inc.
Reaction of OH radical with mono‐, di‐, and trichloroacetaldehyde: an ab initio study
Authors: Chandra Asit K. , Uchimaru Tadafumi
Published: August 2002

The hydrogen abstraction reactions between chlorine‐substituted acetaldehydes and OH radicals have been investigated by using ab initio molecular orbital theory. Equilibrium geometries and transition‐state structures have been optimized at the (U)MP2/6‐311G(d,p) level. Activation barriers and heats of reaction for different reaction channels have been estimated from the single‐point calculations at the (U)MP2/6‐311G(2df,2p) level. Three, two, and one hydrogen abstraction channel have been found for the mono‐, di‐, and trichloroacetaldehyde, respectively. At a higher temperature region, hydrogen abstraction from the formyl group is found to be the major reaction channel for all the three chloroacetaldehydes. The effect of halogen substitution on reactivity toward hydrogen abstraction has been discussed. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1509–1521, 2001
Erratum
Authors: Lorion Raymond P.
Published: August 2002

The Editor wishes to apologize to Dr. Joanne Pedro‐Carroll and to all who knew of and respected Dr. Emory L. Cowen for the incomplete presentation of authorship on the memorial piece entitled “Remembering Emory L. Cowen” (Journal of Community Psychology, Vol. 29, No. 4, p. 379). The correct authorship should have been:

A. Dirk Hightower, Joanne Pedro‐Carroll, and Raymond P. Lorion

In our haste to acknowledge Emory's life, we mistakenly omitted one of those who contributed to this piece and, most importantly, to his work on children's adjustment to divorce and family disruptions.
Strangers still? The experience of discrimination among Chinese Americans
Authors: Goto Sharon G. , Gee Gilbert C. , Takeuchi David T.
Published: August 2002

This study investigates the perceptions of discrimination within an Asian American community. Over 1,500 Chinese Americans were interviewed regarding experiences with unfair treatment due to their race or ethnicity and their language and or accent. Demographic variables, acculturation level, and amount of contact opportunity were used to predict perceived discrimination using multiple hierarchical logistic analyses. Approximately 21% of Chinese Americans reported being unfairly treated in their lifetime. The specific predictors varied depending on whether the discrimination was due to race and ethnicity, or language and accent. Retention of cultural practices, age of immigration, and contact opportunity were associated with racial discrimination. Only contact opportunity was associated with language and accent discrimination. Implications are discussed with respect to perceptions of similarity, the contact hypothesis, and bicultural adjustment. © 2002 John Wiley & Sons, Inc.
Insulin‐like growth factor binding protein‐2 mediates the inhibition of DNA synthesis by transforming growth factor‐β in mink lung epithelial cells*†
Authors: Dong Feng , WU Hai‐Bin , Hong Jiang , Rechler Matthew M.
Published: August 2002

Insulin‐like growth factor binding protein‐3 (IGFBP‐3) has been proposed to mediate the growth inhibitory effects of transforming growth factor (TGF)‐β in breast and prostate cancer cells. Both TGF‐β and exogenous IGFBP‐3 inhibit DNA synthesis in Mv1 mink lung epithelial cells (CCL64). The present study asks whether IGFBPs synthesized by CCL64 cells mediate growth inhibition by TGF‐β. CCL64 cells synthesize and secrete a single 34‐kDa IGFBP that was identified as IGFBP‐2 by immunoprecipitation and immunodepletion. Recombinant bovine IGFBP‐2 inhibited CCL64 DNA synthesis in serum‐free media in an IGF‐independent manner. Coincubation with Leu60‐IGF‐I, an IGF‐I analog that binds to IGFBPs with higher affinity than to IGF‐I receptors, decreased the inhibition by bIGFBP‐2. Leu60‐IGF‐I also decreased the inhibition of CCL64 DNA synthesis by TGF‐β by up to 70%, whereas Long‐R3‐IGF‐I, an IGF‐I analog with higher affinity for IGF‐I receptors than for IGFBPs, did not decrease inhibition, suggesting that the effect of Leu60‐IGF‐I resulted from its forming complexes with endogenous IGFBPs. Leu60‐IGF‐I did not decrease TGF‐β stimulation of a Smad3‐dependent reporter gene. Following incubation of intact CCL64 cells with bIGFBP‐2 at 0°C, bIGFBP‐2 was recovered in membrane fractions; membrane association was abolished by coincubation with Leu60‐IGF‐I. If exogenous and secreted IGFBP‐2 must bind to CCL64 cells to inhibit DNA synthesis, Leu60‐IGF‐I might reduce the inhibition of DNA synthesis by bIGFBP‐2 or TGF‐β by inhibiting the association of IGFBP‐2 in the media with CCL64 cells. Since TGF‐β does not increase IGFBP‐2 abundance, we propose that TGF‐β sensitizes CCL64 cells to the latent growth inhibitory activity of endogenous IGFBP‐2 by potentiating an intracellular IGFBP‐2 signaling pathway or by promoting the association of secreted IGFBP‐2 with the plasma membrane. J. Cell. Physiol. 190: 63–73, 2002. Published 2002 Wiley‐Liss, Inc.
Inhibition of Caco‐2 cell proliferation by all‐trans retinoic acid: Role of insulin‐like growth factor binding protein‐6
Authors: Kim Eun J. , Kang Young‐Hee , Schaffer Beverly S. , Bach Leon A. , MacDonald Richard G. , Park Jung H.Y.
Published: August 2002

The present study examined the effects of all‐trans retinoic acid (tRA) on proliferation and expression of the IGF system in Caco‐2 human colon adenocarcinoma cells. tRA inhibited Caco‐2 cell proliferation in a dose‐dependent manner, with a 40 ± 2% decrease in cell number observed 48 h after the addition of 1 μM tRA. Ligand blot analysis of IGFBPs in conditioned media revealed that Caco‐2 cells produced three IGFBPs of Mr: 34,000 (IGFBP‐2), 24,000 (IGFBP‐4), and 32,000 (IGFBP‐6). The concentrations of IGFBP‐2 and IGFBP‐4 decreased by 48 ± 6 and 70 ± 13%, respectively, whereas that of IGFBP‐6 increased by 698 ± 20% with 1 μM tRA. tRA decreased mRNA levels of IGFBP‐2 and IGFBP‐4 by 20 ± 3 and 50 ± 8%, respectively, whereas tRA increased IGFBP‐6 mRNA by 660 ± 20%. tRA did not alter levels of IGF‐II mRNA or peptide. To examine if endogenous IGFBP‐6 inhibits cell proliferation, Caco‐2 cells were transfected with an IGFBP‐6 cDNA expression construct or pcDNA3 vector only and stable clones were selected. Clones overexpressing IGFBP‐6 grew more slowly than vector controls and achieved final densities 30–55% lower than those of vector controls. Accumulation of IGFBP‐6 mRNA and concentrations of IGFBP‐6 peptide in conditioned media were increased by 200–250 and 220–250%, respectively, in the IGFBP‐6 clones compared with controls. Increased expression of IGFBP‐6, which has a high binding affinity for IGF‐II, following tRA treatment suggests that the decreased proliferation caused by tRA may result, at least in part, from IGFBP‐6‐mediated disruption of the IGF‐II autocrine loop in these colon cancer cells. J. Cell. Physiol. 190: 92–100, 2002. © 2002 Wiley‐Liss, Inc.
P2Y2 nucleotide receptor signaling in human monocytic cells: Activation, desensitization and coupling to mitogen‐activated protein kinases
Authors: Santiago‐Pérez Laura I. , Flores Rosa V. , Santos‐Berríos Cynthia , Chorna Nataliya E. , Krugh Brent , Garrad Richard C. , Erb Laurie , Weisman Gary A. , González Fernando A.
Published: August 2002

Activation of P2Y2 receptors by extracellular nucleotides has been shown to induce phenotypic differentiation of human promonocytic U937 cells that is associated with the inflammatory response. The P2Y2 receptor agonist, UTP, induced the phosphorylation of the MAP kinases MEK1/2 and ERK1/2 in a sequential manner, since ERK1/2 phosphorylation was abolished by the MEK1/2 inhibitor PD 098059. Other results indicated that P2Y2 receptors can couple to MAP kinases via phosphatidylinositol 3‐kinase (PI3K) and c‐src. Accordingly, ERK1/2 phosphorylation induced by UTP was inhibited by the PI3K inhibitors, wortmannin and LY294002, and the c‐src inhibitors, radicicol and PP2, but not by inhibitors of protein kinase C (PKC). The phosphorylation of ERK1/2 was independent of the ability of P2Y2 receptors to increase the concentration of intracellular free calcium, since chelation of intracellular calcium by BAPTA did not diminish the phosphorylation of ERK1/2 induced by UTP. A 5‐minute treatment with UTP reduced U937 cell responsiveness to a subsequent UTP challenge. UTP‐induced desensitization was characterized by an increase in the EC50 for receptor activation (from 0.44 to 9.3 μM) and a dramatic (∼75%) decrease in the maximal calcium mobilization induced by a supramaximal dose of UTP. Phorbol ester treatment also caused P2Y2 receptor desensitization (EC50 = 12.3 μM UTP and maximal calcium mobilization reduced by ∼33%). The protein kinase C inhibitor GF 109203X failed to significantly inhibit the UTP‐induced desensitization of the P2Y2 receptor, whereas the protein phosphatase inhibitor okadaic acid blocked receptor resensitization. Recovery of receptor activity after UTP‐induced desensitization was evident in cells treated with agonist for 5 or 30 min. However, P2Y2 receptor activity remained partially desensitized 30 min after pretreatment of cells with UTP for 1 h or longer. This sustained desensitized state correlated with a decrease in P2Y2 receptor mRNA levels. Desensitization of ERK1/2 phosphorylation was induced by a 5‐minute pretreatment with UTP, and cell responsiveness did not return even after a 30‐minute incubation of cells in the absence of an agonist. Results suggest that desensitization of the P2Y2 receptor may involve covalent modifications (i.e., receptor phosphorylation) that functionally uncouple the receptor from the calcium signaling pathway, and that transcriptional regulation may play a role in long‐term desensitization. Our results indicate that calcium mobilization and ERK1/2 phosphorylation induced by P2Y2 receptor activation are independent events in U937 monocytes. © 2001 Wiley‐Liss, Inc.
Monocytic cell adhesion to intact and plasmin‐modified fibrinogen: Possible involvement of Mac‐1 (CD11b/CD18) and ICAM‐1 (CD54)
Authors: Arefieva T.L. , Krasnikova Tatiana L.
Published: August 2002

β2‐integrin Mac‐1 and immunoglobulin‐like ICAM‐1 adhesion molecules are expressed by monocytes and both known to bind fibrinogen and its degradation products. Here, we investigated whether fibrinogen cleavage with plasmin modulates the adherence of monocytic cells and what types of adhesion molecules are involved. Using several cell types, characterized by different patterns of Mac‐1 and ICAM‐1 expression, and monoclonal antibodies against β2‐integrins and ICAM‐1 we demonstrate, that fibrinogen cleavage evokes gradual decrease in β2‐integrin‐dependent cell adhesion. Furthermore, generation of the early degradation products, fragments X and Y, by minimum cleavage of fibrinogen stimulates cell adhesion, mediated by ICAM‐1. © 2001 Wiley‐Liss, Inc.
Catalytic wet air oxidation of phenol using active carbon: performance of discontinuous and continuous reactors
Authors: Stüber Frank , Polaert Isabelle , Delmas Henri , Font Josep , Fortuny Agustí , Fabregat Azael
Published: August 2002

Catalytic wet air oxidation (CWAO) of an aqueous phenol solution using active carbon (AC) as catalytic material was compared for a slurry and trickle bed reactor. Semi‐batchwise experiments were carried out in a slurry reactor in the absence of external and internal mass transfer. Trickle‐bed runs were conducted under the same conditions of temperature and pressure. Experimental results from the slurry reactor study showed that the phenol removal rate significantly increased with temperature and phenol concentration, whereas partial oxygen pressure had little effect. Thus, at conditions of 160 °C and 0.71 MPa of oxygen partial pressure, almost complete phenol elimination was achieved within 2 h for an initial phenol concentration of 2.5 g dm−3. Under the same conditions of temperature and pressure, the slurry reactor performed at much higher initial rates with respect to phenol removal than the trickle bed reactor, both for a fresh active carbon and an aged active carbon, previously used for 50 h in the trickle bed reactor, but mineralisation was found to be much lower in the slurry reactor. Mass transfer limitations, ineffective catalyst wetting or preferential flow in the trickle bed alone cannot explain the drastic difference in the phenol removal rate. It is likely that the slurry system also greatly favours the formation of condensation polymers followed by their irreversible adsorption onto the AC surface, thereby progressively preventing the phenol molecules to be oxidised. Thus, the application of this type of reactor in CWAO has to be seriously questioned when aiming at complete mineralisation of phenol. Furthermore, any kinetic study of phenol oxidation conducted in a batch slurry reactor may not be useful for the design and scale‐up of a continuous trickle bed reactor.

© 2001 Society of Chemical Industry
Liquid phase hydrogenation of benzene to cyclohexene on ruthenium catalysts supported on zinc oxide‐based binary oxides
Authors: Hu Sung‐Cheng , Chen Yu‐Wen
Published: August 2002

A series of binary oxide‐supported ruthenium catalysts with zinc oxide as a component of the support was prepared. Zinc oxide was a major component of the support, the other component was lanthanum oxide, zirconium oxide, chromium oxide, barium oxide, gallium oxide, strontium oxide, calcium oxide or magnesium oxide. Liquid phase hydrogenation of benzene to cyclohexene was studied on these catalysts in a stirred tank reactor at a hydrogen pressure of 2.5–6.0 MPa and 448 K. The reaction was operated in a kinetic‐controlled regime. In order to have high selectivity to cyclohexene, a large amount of water should be present. In addition, the reaction medium should be an alkaline solution. The yield of cyclohexene was in the order: Ru/Ga2O3–ZnO > Ru/La2O3–ZnO > Ru/Cr2O3–ZnO > Ru/ZrO2–ZnO > Ru/MgO–ZnO = Ru/CaO–ZnO = Ru/SrO–ZnO = Ru/BaO–ZnO.Ru/Ga2O3–ZnO demonstrated the highest selectivity and yield of cyclohexene. A model of the low solubilities of reactants in the water film surrounding the catalyst can explain the reaction behavior of the catalyst.

© 2001 Society of Chemical Industry
Adsorption and desorption characteristics of zinc on ash particles derived from oil palm waste
Authors: Chu Khim Hoong , Hashim Mohd Ali
Published: August 2002

Solid waste such as palm fibre and shell produced by the palm oil industry is used by palm oil mills as boiler fuel to produce steam for electricity generation. The ash produced after combustion creates a disposal problem for the palm oil industry. This study explored the potential of oil palm ash as an adsorbent material for removal and recovery of zinc ions from aqueous solutions. The equilibrium uptake of zinc was found to increase with solution pH in the range 3–6, yielding a maximum adsorption capacity of 0.163 mmol g−1 of ash at a pH of 6. The affinity constant of oil palm ash was found to greatly exceed that of a commercial ion exchange resin, suggesting that oil palm ash may find potential application in treating dilute zinc‐containing waste streams. Four isotherm models were used to fit the constant pH equilibrium isotherms obtained at four different pH values. The entire data set was successfully simulated using two of the isotherm models: a Langmuir model with pH‐dependent parameters and an extended Langmuir–Freundlich model with pH‐independent parameters. The rates of adsorption and desorption for zinc were measured using a stirred‐batch contactor. The contact time required to reach apparent adsorption equilibrium was found to decrease with increasing adsorbent dosage. Both the rate and the extent of zinc desorption were affected by the pH of the desorbing solution. The adsorption and desorption rates were consistent with simple first‐order rate models.

© 2002 Society of Chemical Industry
Identification, characterization, and physiological actions of factor H as an adrenomedullin binding protein present in human plasma
Authors: Pío Rubén , Elsasser Ted H. , Martínez Alfredo , Cuttitta Frank
Published: August 2002

A recently discovered adrenomedullin binding protein has been characterized as complement factor H, an important regulator of the complement cascade. This review will describe the evidence that led to the identification of factor H as an adrenomedullin binding protein and will address the implications that such binding has in the radioimmunoassay of AM in plasma. We will also describe the possible physiological implications of AM binding: namely, factor H suppresses the antimicrobial activity of AM, enhances AM‐mediated induction of cyclic‐AMP in rat fibroblasts, and augments the AM‐mediated growth of a human cancer cell line. These initial studies suggest that factor H may be an important factor in the regulation of AM physiology. The elucidation of the mechanisms that modulate AM activity will be necessary for the understanding of the role of AM in normal and pathological conditions. Microsc. Res. Tech. 57:23–27, 2002. © 2002 Wiley‐Liss, Inc.
Are lymphocytic monoclonality and immunoglobulin heavy chain (IgH) rearrangement premalignant conditions in chronic gastritis?
Authors: Wündisch Thomas , Thiede Christian , Alpen Birgit , Stolte Manfred , Neubauer Andreas
Published: August 2002

Normal gastric mucosa is devoid of lymphoid cells. Any increase of lymphocytes suggests chronic inflammation. Infection with Helicobacter pylori (Hp) is the major cause for nonautoimmune chronic gastritis and induces a mixed cellular response resulting in an acquired lymphoid tissue, or MALT (mucosa‐associated lymphoid tissue). Hp has also been implicated in the genesis of gastric MALT‐lymphoma. Polymerase chain reaction‐based assays to detect the expansion of monoclonal B‐cells have also been used to corroborate the diagnosis. In a considerable number of cases monoclonal B‐cells remain detectable in follow‐up biopsies, with the lymphoma being in complete histological remission. The clinical relevance of this finding is not clear yet. However, there also exist different reports that monoclonal B‐cells can be found in gastric biopsies of patients with neither a histological sign nor a present or past history of lymphoma. In the light of these findings we address the question whether B‐cell monoclonality can be seen as a premalignant condition in chronic gastritis and conclude that as of now the relevance of the finding of B‐cell monoclonality remains unclear. As of now the only and gold standard for the diagnosis of gastric MALT‐lymphoma is histopathology. Microsc. Res. Tech. 53:414–418, 2001. © 2001 Wiley‐Liss, Inc.
Exposure to exogenous DNA can modify the sensitivity of the Fas apoptotic pathway
Authors: de Carvalho Bittencourt Marcelo , Saas Philippe , Fresnay Stéphanie , Yerly‐Motta Véronique , Ferrand Christophe , Perruche Sylvain , Duperrier Anne , Hervé Patrick , Tiberghien Pierre , Chalmers David E.
Published: August 2002

Background

Gene‐transfer techniques are commonly employed for both in vitro and in vivo studies. However, modifications of the target cell following the introduction of the gene of interest are not often examined. These modifications can alter the immunogenicity and/or the susceptibility of the target cell to apoptosis and may produce unwanted consequences in vivo.

Methods

Gene transfer into the murine fibroblastic Ψ‐CRIP packaging cellline was performed using calcium phosphate precipitation, cationic liposome–DNA complexes or a retroviral RNA‐mediated method. After gene transfer, Fas expression, cytokine production, and sensitivity to Fas ligand (FasL)‐mediated death were assessed.

Results

Following transfection of a FasL expression vector by calcium phosphate precipitation, an unexpected increase was observed in apoptotic cell death in previously Fas‐resistant Ψ‐CRIP cells. This apoptosis was due to Fas upregulation and an increase of sensitivity to FasL‐mediated death. Other plasmids coding non‐cytotoxic factors also modulated this apoptotic pathway. Theco‐stimulatory molecule CD80 was also upregulated. Exposure to naked DNA alone elicited the same response. The effect was not dependent on the methylation status of exogenous DNA, but was found to be dependent on the target cell type and might be avoided by the use of an RNA‐mediated retroviral system.

Conclusions

Plasmid transfection or simple exposure to naked DNA can increase sensitivity to apoptosis. The generation of FasL packaging cell lines is therefore limited by an increase in FasL/Fas‐mediated apoptosis. These findings should be considered when using genetically modified transplantable cells in order to prevent elimination by host cytotoxic cells and in particular when cells are engineered using FasL. Copyright © 2001 John Wiley & Sons, Ltd.
Adenovirus or HA‐2 fusogenic peptide‐assisted lipofection increases cytoplasmic levels of plasmid in nondividing endothelium with little enhancement of transgene expression
Authors: Subramanian Ajit , Ma Haiching , Dahl Kris N. , Zhu Jingya , Diamond Scott L.
Published: August 2002

Background

Adenovirus‐assisted lipofection has been reported to increase transfection efficiency through mechanisms potentially involving endosome escape and/or nuclear targeting activity. Similarly, transfection with the viral fusogenic peptide HA‐2 of the influenza virus hemagglutinin can increase transfection efficiency. However, there are few studies examining the mechanism and intracellular trafficking of these viral and/or viral fusogenic peptide‐assisted lipofections.

Methods and results

Endosome escape was directly assayed with T7 RNA polymerase bound to plasmid (pTMβgal) expressing β‐galactosidase under a T7 promoter to detect transcribable plasmid that escapes the endosomal compartment. Lipofection of pTMβgal with replication‐deficient adenovirus (Ad5‐null) at a multiplicity of infection (MOI) of 100 and 1000 increased cytoplasmic levels of transcribable plasmid by 24‐ and 117‐fold, respectively, over lipofection alone, without an effect on total plasmid uptake. However, lipofection of pCMVβgal with Ad5‐null at a MOI of 100 and 1000 increased transgene expression only seven‐ and eight‐fold, respectively, over lipofection alone. Thus, a 24‐fold increase in endosome escape saturated expression from pCMVβgal and provided only a seven‐fold benefit in nondividing cells, which was not significantly increased with further increases in endosome escape. A cationic form of HA‐2 (HA‐K4) also caused significant enhancements in endosome escape, as detected with the cytoplasmic transcription assay. However, HA‐K4 enhancement of endosome escape did not correlate with transgene expression from pCMVβgal, consistent with the detection of HA‐K4‐mediated partitioning of plasmid to the insoluble fraction of the cell lysate.

Conclusion

These results indicate that enhancement of endosome escape in nondividing cells does not fully alleviate rate limits related to nuclear import of the plasmid. Copyright © 2001 John Wiley & Sons, Ltd.
On splittable colorings of graphs and hypergraphs
Authors: Füredi Zoltán , Ramamurthi Radhika
Published: August 2002

The notion of a split coloring of a complete graph was introduced by Erdős and Gyárfás [7] as a generalization of split graphs. In this work, we offer an alternate interpretation by comparing such a coloring to the classical Ramsey coloring problem via a two‐round game played against an adversary. We show that the techniques used and bounds obtained on the extremal (r,m)‐split coloring problem of [7] are closer in nature to the Turán theory of graphs rather than Ramsey theory. We extend the notion of these colorings to hypergraphs and provide bounds and some exact results. © 2002 Wiley Periodicals, Inc. J Graph Theory 40: 226–237, 2002
Empowerment at last?
Authors: Moore Mick
Published: August 2002

The World Bank and other international development agencies have declared empowerment to be central to their anti‐poverty programmes. They are vague over meaning, and may be using the term partly to advance their own organizational interests. The term may imply more political confrontation than international organizations are able to cope with. If they to take empowerment seriously, they need to think more about practical strategies. Their best approach might be indirect and parametric, rather than direct and interventionist: helping to create a political environment that enables poor people to organize themselves, rather than by supporting poor peoples' organizations directly. Copyright © 2001 John Wiley & Sons, Ltd.
Attacking Poverty: but what happened to urban poverty and development?
Authors: Amis Philip
Published: August 2002

This paper reviews Attacking Poverty with regard to its treatment of urban poverty. The central argument is that urbanization and urban poverty are increasingly important but are largely ignored in the report. Thus the dynamics of urban poverty are overlooked and the subsequent policy suggestions are subsequently weakened. The report's emphasis on empowerment misses the historically progressive nature of urbanization as a social force. Copyright © 2001 John Wiley & Sons, Ltd.
Promises kept: enforcement and the role of rotating savings and credit associations in an economy
Authors: Chiteji N. S.
Published: August 2002

Rotating savings and credit associations (roscas) are a popular form of informal finance in developing countries. This paper examines the rosca's ability to enforce its terms of membership and the implications that this has for their existence in an economy. A connection between enforcement costs and the desirability of rosca formation is illustrated using a framework that focuses on the nature of the financial contract that the rosca offers, allowing inferences to be drawn about the likely viability of roscas throughout the development process and the implications this has for debates about financial dualism. Copyright © 2002 John Wiley & Sons, Ltd.
Putting context into ICTs in international development: an institutional networking project in Vietnam
Authors: Boyle Grant
Published: August 2002

This paper questions the adequacy of the technological orientation present in many popular discussions over the role of information and communications technologies (ICTs) in international development. In particular, the paper considers the impact of technology on how programme goals and development problems are understood, by relating critical computer design literature to the experience of deploying an Internet‐based research network in a university capacity‐building programme in Vietnam. The current technology‐focused discourse leads such work to tend to be envisioned merely in terms of selected means, such as ICT connectivity or skills. However, it is only through discussion of the ends, not means, of ICT deployment that the complexity of such deployment can be adequately understood. Copyright © 2002 John Wiley & Sons, Ltd.