bluuebunny/crossref_metadata_2025_split 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

AbstractBiodegradable 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

AbstractTissue 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

AbstractThe 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

AbstractOsteoblasts 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

AbstractCCAAT/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

AbstractNormal 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

AbstractStudies 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

AbstractMechanisms 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

AbstractAntioxidants 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

AbstractAlthough 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

AbstractThe 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

AbstractThe 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. LorionIn 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

AbstractThis 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.