bluuebunny/crossref_metadata_2025 huggingface dataset:
Neuronal number, volume, and apoptosis of the left dentate gyrus of chronically stressed pigs correlate negatively with basal saliva cortisol levels
Authors: van der Beek Eline M. , Wiegant Victor M. , Schouten Willem G.P. , van Eerdenburg Frank J.C.M. , Loijens Leanne W.S. , van der Plas Carianne , Benning Marjan A. , de Vries Hester , de Kloet E. Ron , Lucassen Paul J.
Published: April 2004

Although the consequences of stress and hypercortisolemia for the rodent hippocampal dentate gyrus (DG) are well known, little is known about other species. For pigs, tethered housing represents a well‐established chronic stressor that shares many similarities with restraint paradigms, as evidenced by profound changes in behavior and autonomic and endocrine dysfunction, including flattened cortisol rhythms and hypercortisolemia—all conditions that may threaten hippocampal viability in rat. Here, we studied structural parameters of the porcine DG after 5 months of tethered housing in relation to basal saliva cortisol measured antemortem. We further investigated whether any neuropathology or alterations in apoptosis had occurred in the left hippocampal hemisphere. Stereological analysis revealed high correlations between DG volume and neuron number in individual animals in both hemispheres. Within individual animals, neuron numbers of the left and right lobes were not correlated. Notably, basal cortisol was negatively correlated with volume and neuron number of the left, but not the right DG. Although obvious neuropathology was absent, apoptosis was present in DG and alveus and less so in CA areas. Despite the short window of time during which apoptosis is detectable, their stereologically estimated numbers in the DG, but not in other regions, were negatively correlated with cortisol. In conclusion, our data indicate for the first time a profound lateralization in the relationship between DG structure, apoptosis, and basal cortisol after stress in pigs. Five months of chronic stress failed to induce lasting neuropathology. Although accumulating changes in apoptosis could have contributed to the structural DG alterations, further studies should reveal whether stress has been instrumental, or whether the differences between animals were present from birth onward. The present lateralization after stress is, however, consistent with lateralized hippocampal volume changes in stress‐related human disorders and suggests that these effects are not limited to this species alone. © 2004 Wiley‐Liss, Inc.
Intrahippocampal administration of BDNF in adult rats affects short‐term behavioral plasticity in the Morris water maze and performance in the elevated plus‐maze
Authors: Cirulli Francesca , Berry Alessandra , Chiarotti Flavia , Alleva Enrico
Published: April 2004

The present study evaluated the effects of a single intrahippocampal administration of brain‐derived neurotrophic factor (BDNF) on memory retention in a water maze. Adult rats were trained in a water maze (acquisition phase, day 1). Immediately after the last training trial subjects were injected in the right hippocampus with either BDNF (24 μg) or phosphate‐buffered saline (1 μl). On day 2, all subjects were tested for memory retention in a probe trial and were subsequently tested for reversal learning. While no differences emerged in the probe trial, BDNF‐treated subjects showed a shorter latency and a shorter path length to reach the platform during the reversal phase. A significant difference in their “turn angle” and in their swim paths suggests that they might have used a different search strategy compared with controls. Moreover, all subjects also underwent an elevated‐plus maze test. BDNF‐treated‐animals showed a clear tendency to spend a greater amount of time in the open arms and a significantly higher frequency of grooming behavior and of the stretched‐attend posture in this maze area, but no differences in locomotion. Overall, these results indicate that administration of BDNF improves performance in a spatial memory task and has enduring effects on emotional behavior. © 2004 Wiley‐Liss, Inc.
Distribution of metabotropic GABA receptor subunits GABAB1a/b and GABAB2 in the rat hippocampus during prenatal and postnatal development
Authors: López‐Bendito Guillermina , Shigemoto Ryuichi , Kulik Akos , Vida Imre , Fairén Alfonso , Luján Rafael
Published: April 2004

Metabotropic γ‐aminobutyric acid receptors (GABAB) play modulatory roles in central synaptic transmission and are involved in controlling neuronal migration during development. We used immunohistochemical methods to elucidate the expression pattern as well as the cellular and the precise subcellular localization of the GABAB1a/b and GABAB2 subunits in the rat hippocampus during prenatal and postnatal development. At the light microscopic level, both GABAB1a/b and GABAB2 were expressed in the hippocampal primordium from embryonic day E14. During postnatal development, immunoreactivity for GABAB1a/b and GABAB2 was distributed mainly in pyramidal cells, with discrete GABAB1a/b‐immunopositive cell bodies of interneurons present throughout the hippocampus. Using double immunofluorescence, we demonstrated that during the second week of postnatal development, GABAB1a/b but not GABAB2 was expressed in glial cells throughout the hippocampal formation. At the electron microscopic level, GABAB1a/b and GABAB2 showed a similar distribution pattern during postnatal development. Thus, at all ages the two receptor subunits were located postsynaptically in dendritic spines and shafts at extrasynaptic and perisynaptic sites in both pyramidal and nonpyramidal cells. We further demonstrated that the two subunits were localized presynaptically along the extrasynaptic plasma membrane of axon terminals and along the presynaptic active zone in both asymmetrical and, to a lesser extent, symmetrical synapses. These results suggest that GABAB receptors are widely expressed in the hippocampus throughout development and that GABAB1a/b and GABAB2 form both pre‐ and postsynaptic receptors. © 2004 Wiley‐Liss, Inc.
Vascular adventitia generates neuronal progenitors in the monkey hippocampus after ischemia
Authors: Yamashima Tetsumori , Tonchev Anton B. , Vachkov Ivan H. , Popivanova Boryana K. , Seki Tatsunori , Sawamoto Kazunobu , Okano Hideyuki
Published: April 2004

In the adult hippocampus, neurogenesis proceeds in the subgranular zone (SGZ) of the dentate gyrus (DG), but not in the cornu Ammonis (CA). Recently, we demonstrated in monkeys that transient brain ischemia induces an increase of the neuronal progenitor cells in the SGZ, but not in CA1, in the second week after the insult. To identify the origin of primary neuronal progenitors in vivo, we compared the postischemic monkey DG and CA1, using light and electron microscopy, focusing on specific phenotype markers, as well as the expression of neurotrophic factors. Laser confocal microscopy showed that 1–3% of 5‐bromo‐2′‐deoxyuridine (BrdU)‐positive cells in the SGZ after 2–96 h labeling were also positive for neuronal markers such as TUC4, βIII tubulin, and NeuN on days 9 and 15. In contrast, despite the presence of numerous BrdU‐positive cells, CA1 showed no neurogenesis at any time points, and all the progenitors were positive for glial markers: Iba1 or S‐100β on days 4, 9, and 15. Highly polysialylated neural cell adhesion molecule (PSA‐NCAM)‐positive cells were abundant in the SGZ, but were absent in CA1. On day 9, most of the immature neurons positive for βIII‐tubulin in SGZ showed an increase in PSA‐NCAM immunoreactivity. The immunoreactivity of brain‐derived neurotrophic factor (BDNF) was abundant at the vascular adventitia of the SGZ, but was absent at the adventitia of CA1. BrdU‐positive progenitor cells were frequently seen in the vicinity of proliferating blood vessels. Ultrastructural analysis indicated that most of the neuronal progenitor cells and microglia originated from the pericytes of capillaries and/or adventitial cells of arterioles (called vascular adventitia). The detaching adventitial cells showed mitotic figures in the perivascular space, and the resultant neuronal progenitor cells made contact with dendritic spines associated with synaptic vesicles or boutons. These data implicate the vascular adventitia as a novel potential source of neuronal progenitor cells in the postischemic primate SGZ. © 2004 Wiley‐Liss, Inc.
Fos induction and persistence, neurodegeneration, and interneuron activation in the hippocampus of epilepsy‐resistant versus epilepsy‐prone rats after pilocarpine‐induced seizures
Authors: Fabene Paolo F. , Andrioli Anna , Priel Margareth R. , Cavalheiro Esper A. , Bentivoglio Marina
Published: April 2004

Previous studies demonstrated that the spiny rat Proechimys guyannensis exhibits resistance to experimental epilepsy. Neural activation was studied in the Proechimys hippocampus, using Fos induction, within 24 h after pilocarpine‐induced seizures; neurodegenerative events were investigated in parallel, using FluoroJade B histochemistry. These parameters were selected since pilocarpine‐induced limbic epilepsy is known to elicit immediate early gene expression and cell loss in the hippocampus of seizure‐prone laboratory rodents. At variance with matched experiments in Wistar rats, pilocarpine injection resulted in Proechimys in seizure episodes that, as previously reported, did not develop into status epilepticus. At 3 h and 8 h after seizure onset, Fos immunoreactivity filled the dentate gyrus of both rat species, and was quite marked in pyramidal cells of the Proechimys Ammon's horn. At 24 h, Fos immunoreactivity dropped in the Wistar hippocampus and persisted in Proechimys. At 8 h and 24 h, FluoroJade‐stained neurons were very few in the Proechimys hippocampus, whereas they were abundant in that of Wistar rats. Double immunohistochemistry for Fos and parvalbumin, the protein expressed by fast‐spiking hippocampal interneurons, indicated that Fos was induced up to 24 h in the vast majority of parvalbumin‐containing cells of the Proechimys hippocampus, and in a minority of these cells in the Wistar hippocampus. The findings demonstrate that early postepileptic neurodegeneration is very limited in the Proechimys hippocampus, in which sustained Fos induction persists for several hours. The findings also indicate that Fos induction and persistence may not correlate with seizure intensity and may not be associated with neuronal death. Finally, the data implicate differential mechanisms of interneuron activity in anti‐convulsant and pro‐convulsant phenomena. © 2004 Wiley‐Liss, Inc.
Epidemiology Of Hodgkin's disease: a review
Authors: Cartwright R. A. , Watkins Gillian
Published: April 2004

The descriptive and aetiological epidemiology of Hodgkin's Disease (HD) are reviewed. Key issues which are highlighted include the evidence suggesting that HD is a complex of related conditions that are part mediated by infectious diseases, immune deficits and genetic susceptibilities. There is little convincing evidence to suggest any other environmental factors are involved in the aetiology. The apparent changing pattern of disease by time and from country to country, needs careful future study. Copyright © 2004 John Wiley & Sons, Ltd.
Repair of calvarial defects in rats by prefabricated hydroxyapatite cement implants
Authors: Schliephake H. , Gruber R. , Dard M. , Wenz R. , Scholz S.
Published: April 2004

The aim of the present study was to test the hypothesis that calvarial defects can be repaired by using preformed implants of calcium phosphate bone cement (CPBC) in rats. Sixty adult female Sprague–Dawley rats received full‐thickness calvarial nonhealing defects with a diameter of 8 mm. Three different CPBCs were used: group 1: tetracalcium phosphate‐based powder; group 2: a blend of amorphous and crystalline calcium phosphate precursors; and group 3: an alpha‐tricalcium phosphate (α‐TCP)‐based powder. Implants were left to cure for 25–40 min at room temperature in a silicon mold of 7.9 mm and inserted press fit into the defects. Fifteen animals served as unfilled controls. After 13, 26, and 52 weeks, the material was analyzed qualitatively by using surface‐stained undecalcified thick‐section specimens and quantitatively by using semiautomated histometry. Kruskal–Wallis tests were applied to compare mean values of periimplant bone formation at a significance level of p < 0.05. Three implants of group 1 fractured during insertion. Resorption of CPBC without complementary bone formation was noticed in these implants. Unfractured implants were resorbed with simultaneous apposition of bone on the implant surface. After 52 weeks, the resorption rate varied between 23.1 and 39.3%. Periimplant bone formation increased continuously on average around all implant types, but it reached statistical significance only in group 2. The results showed that repair of calvarial defects can be achieved by preformed CPBC implants. The rate of resorption of preformed implants is, however, much lower than that reported for in vivo cured CPBC. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 382–390, 2004
Protein‐coated poly(L‐lactic acid) fibers provide a substrate for differentiation of human skeletal muscle cells
Authors: Cronin Elizabeth M. , Thurmond Frederick A. , Bassel‐Duby Rhonda , Williams R. Sanders , Wright Woodring E. , Nelson Kevin D. , Garner Harold R.
Published: April 2004

Tissue engineering represents a potential method for repairing damaged skeletal muscle tissue. Extracellular matrix (ECM) proteins were evaluated for their ability to aid in cell attachment, whereas a poly(L‐lactic acid) (PLLA) fiber scaffold was tested as a substrate for the differentiation of human skeletal muscle cells. In comparison to uncoated or gelatin‐coated PLLA films, cell attachment increased significantly (p < 0.001) on PLLA films coated with ECM gel, fibronectin, or laminin. Myoblasts differentiated into multinucleated myofibers on ECM gel‐coated PLLA fibers, and expressed muscle markers such as myosin and α‐actinin. Oligonucleotide microarray analysis showed similar gene expression profiles for human skeletal muscle cells on ECM gel‐coated PLLA fibers as to that observed for myofibers on tissue culture plates. Therefore, PLLA fibers coated with ECM proteins provide a scaffold for the development of skeletal muscle tissue for tissue engineering and cell transplantation applications. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 373–381, 2004
Quantifying the effect of resin type and sterilization method on the degradation of ultrahigh molecular weight polyethylene after 4 years of real‐time shelf aging
Authors: Willie Bettina M. , Ashrafi Shadi , Alajbegovic Sanjin , Burnett Trever , Bloebaum Roy D.
Published: April 2004

Alternative sterilization methods including ethylene oxide, gas plasma, and gamma‐radiation in an inert environment were implemented in the late 1990s, to limit oxidative degradation of ultrahigh molecular weight polyethylene (PE). There was also a simultaneous transition to PE resins that did not contain calcium stearate. Shelf storage duration of PE inserts following gamma‐irradiation in air has been correlated to poor clinical performance and increased wear. This study aimed to determine how sterilization method and resin type influenced degradation of PE after 4 years of real‐time shelf aging. It was hypothesized that gamma‐irradiation and stearate containing resins would incur significantly more degradation than nonradiated, stearate‐free resins. Gamma‐irradiated PE samples in air and nitrogen had a significantly increased density and oxidation index, compared to nonirradiated PE after 4 years of shelf aging. Alternative sterilization methods such as ethylene oxide and gas plasma appeared to have significantly less oxidation regardless of PE resin type. A partial correlation demonstrated that density and oxidation index were not correlated (r2 = 0.079) when examining the influence of sterilization method. The data supported that after 4 years of real‐time shelf aging, the type of sterilization method had a larger influence on PE degradation than resin type. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 477–489, 2004
Molecular release from a polymeric microreservoir device: Influence of chemistry, polymer swelling, and loading on device performance
Authors: Grayson Amy C. Richards , Cima Michael J. , Langer Robert
Published: April 2004

A polymeric microreservoir device for controlled‐release drug delivery relies on the degradation of thin poly(lactic‐co‐glycolic acid) membranes that seal each reservoir to achieve pulsatile drug delivery. In vitro release studies in which the swelling of the reservoir membranes was measured indicate a correlation between the release times of various radiolabeled molecules from the devices and the time at which the maximum membrane swelling was observed. Varying the chemistry (lipophilicity/hydrophilicity) or molecular weight of the molecules loaded into the devices did not appear to affect the degree of membrane swelling that was observed, or the time at which the molecules were released from the devices. The amount of drug that was loaded into the reservoirs also did not appear to affect the observed release time of the drug from the device, a significant departure from the behavior of many matrix‐type polymeric drug delivery systems. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 502–512, 2004
Selective protein adsorption and blood compatibility of hydroxy‐carbonate apatites
Authors: Takemoto Shinji , Kusudo Yuko , Tsuru Kanji , Hayakawa Satoshi , Osaka Akiyoshi , Takashima Seisuke
Published: April 2004

We examined the blood compatibility and protein adsorption on hydroxyapatite and hydroxy‐carbonate apatite. Those apatites were synthesized under a 0, 5, or 15% CO2‐containing N2 atmosphere by a wet‐chemical method with a strong ammonia alkali solution of calcium nitrate and diammonium hydrogen phosphate (5:3 in molar ratio) and subsequent calcination in the range of 105–700°C. From infrared (IR) analysis, the carbonate ions substituted both phosphate ions and hydroxyl ions in the hydroxyapatite lattice; the intensities of IR bands assignable to phosphate ions and hydroxyl ions were reduced on calcinations. The specific surface areas of synthesized apatites decreased with increasing calcination temperature. Blood‐clotting properties were evaluated in terms of active partial thromboplastin time, prothrombin time, and the amount of fibrinogen for the plasma in contact with the apatites, indicating that all the apatites barely influenced the blood clotting system. The apatites were in contact with a solution containing both bovine serum albumin (BSA) and β2‐microglobulin (β2‐MG), and the amounts of those proteins adsorbed on them were examined: the amount of absorbed BSA and β2‐MG gradually increased with the calcination temperature below 500°C, while it showed a sudden increase when more than 600°C. Hydroxy‐carbonate apatite synthesized under a 15% CO2‐containing N2 atmosphere and calcined below 400°C had the greatest selectivity in adsorbing β2‐MG. Thus, a higher selectivity for β2‐MG adsorption was empirically correlated to carbonate ions incorporated in the hydroxyapatite lattice. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 69A: 544–551, 2004
Effect of SACCHACHITIN on keratinocyte proliferation and the expressions of type I collagen and tissue‐transglutaminase during skin wound healing
Authors: Hung Wei‐Sheng , Lai Wen‐Fu T. , Leu Bowen , Su Ching‐Hua , Fang Chia‐Lang , Tsai Yu‐Hui
Published: April 2004

SACCHACHITIN is a skin wound‐healing membrane made of residual fruiting body of Ganoderma tsugae. Its effect on proliferating cell nuclear antigen (PCNA) expression in actively proliferating cells, type I collagen expression and tissue remodeling in the healing tissue, and the association of tissue‐transglutaminase (t‐TGase) with wound healing were investigated by immunohistochemical staining. The results demonstrated that PCNA expressed in keratinocytes since day 1 in the SACCHACHITIN group and persisted during entire healing process. In contrast, it was barely detectable on day 3 in the control group. At keratinocyte layer, the SACCHACHITIN group exhibited more type I collagen than did the control group since day 1. At scar tissue, type I collagen was positively stained in the SACCHACHITIN group since day 7 but not in the control group till day 12. Furthermore, t‐TGase was strongly expressed on the inner wall of angiogenic vessels on day 5 of the control group but not on that of the SACCHACHITIN group until day 10. The earlier expressions of PCNA and type I collagen in the keratinocyte layer may lead to accelerated skin wound healing. In addition, the later expression of t‐TGase, an indicator of apoptosis, on the inner wall of angiogenic capillaries in the SACCHACHITIN group may indicate a longer period of blood supply to the wound area, thus facilitating wound healing. These observed phenomena might underline the beneficial effects of SACCHACHITIN membrane on rapid wound healing. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 122–129, 2004
Structural design of the dry fibrin sealant dressing and its impact on the hemostatic efficacy of the product
Authors: Pusateri Anthony E. , Kheirabadi Bijan S. , Delgado Angel V. , Doyle James W. , Kanellos Jerry , Uscilowicz John M. , Martinez Raul S. , Holcomb John B. , Modrow Harold E.
Published: April 2004

We compared the hemostatic efficacy of a production version of a dry fibrin sealant dressing (DFSD) to a prototype that was previously successful in large animal studies. The results were used to improve manufacturing processes. Grade‐V liver injuries were induced in swine and treated with gauze sponges (GAU), the prototype dressings (DFSD‐1), or the scaled‐up production version dressings (DFSD‐2 in experiment 1 and DFSD‐3 in experiment 2). Blood loss, hemostasis, resuscitation volume, and 60‐min survival were quantified. In experiment 1, the DFSD‐1 treatment reduced blood loss (p < 0.01), increased hemostasis at 4 min (p < 0.05), and improved survival (p < 0.05) compared with GAU. The DFSHD‐2 decreased blood loss (p < 0.05) but did not increase hemostasis or survival significantly. Based on these results, manufacturing processes were altered, producing DFSD‐3. In experiment 2, the DFSD‐1 and DFSD‐3 were equally effective in reducing blood loss (p < 0.01) and resuscitation volume (p < 0.05) compared with GAU. Hemostasis occurred more frequently in both the DFSD‐1 and DFSD‐3 groups (p < 0.01) compared with GAU. The structural design of DFSD‐2 did not meet the efficacy requirement for release of the product. The subsequent change incorporated in DFSD‐3 improved all hemostatic parameters of the dressings equal to those of the prototype product. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 114–121, 2004
Electrochemical properties of suprastructures galvanically coupled to a titanium implant
Authors: Oh Keun‐Taek , Kim Kyoung‐Nam
Published: April 2004

In recent years, dental implants have been widely used for the aesthetic and functional restoration of edentulous patients. Dental implants and restorative alloys are required with high corrosion resistance. Suprastructures and implants of different compositions in electrical contact may develop galvanic or coupled corrosion problems. In addition to galvanic corrosion, crevice and pitting corrosion may occur in the marginal gap between dental implant assemblies. In this study, gold, silver–palladium, cobalt–chromium, and nickel–chromium suprastructures were used to investigate their galvanic and crevice corrosion characteristics in combination with titanium (Ti) implants. Potentiodynamic and potentiostatic testing were performed in artificial saliva at 37°C. Potentiodynamic testing was carried out at the potential scan rate of 1 mV/s in the range of −600–1600 mV (SCE). Potentiostatic testing was performed with an open‐circuit potential and current densities at −250, 0, and 250 mV (SCE) in artificial saliva. After electrochemical testing, surface morphologies and cross‐sections were examined using micrographs of the samples. Potentiodynamic test results indicated that suprastructure/Ti implant couples produced passive current densities in the range of 0.5–12 μA/cm2; Ti abutment/Ti implant and gold/Ti implant couples exhibited relatively low passive current densities; Co–Cr/Ti implant couples the highest. Co–Cr and Ni–Cr/Ti implant couples showed breakdown potentials of 700 and 570 mV (SCE), respectively. The open‐circuit potentials of silver, Ti abutment, gold, Ni–Cr, and Co–Cr/Ti implant couples were −93.2 ± 93.9, −123.7 ± 58.8, −140.0 ± 80.6, −223.5 ± 35.1, and −312.7 ± 29.8 mV (SCE), respectively, and did not change with immersion time. The couples exhibited cathodic current densities at −250 mV (SCE); in particular, gold and silver alloys showed high cathodic current densities of −3.18 and −6.63 μA/cm2, respectively. At 250 mV (SCE), Ti abutment/Ti implant couples exhibited a minimum current density of 9.48 × 10−2 μA/cm2, but gold, Ni–Cr, Co–Cr, and silver/Ti implant couples exhibited 0.313, 1.27, 5.60, and 8.06 μA/cm2, respectively. All couples exhibited relatively low current densities at 0 mV (SCE). Photomicrographs after electrochemical testing showed crevice or pitting corrosion in the marginal gap and at the suprastructure surface. Although of the tested samples Co–Cr/Ti implant couples showed the possibility of galvanic corrosion, its degree was not significant. However, it should be borne in mind that galvanic corrosion can accelerate localized corrosion, such as crevice or pitting corrosion. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 318–331, 2004
High release of antibiotic from a novel hydroxyapatite with bimodal pore size distribution
Authors: Hasegawa Masahiro , Sudo Akihiro , Komlev Vladimir S. , Barinov Serguei M. , Uchida Atsumasa
Published: April 2004

We developed a novel hydroxyapatite (HA) cylinder (HA‐A) and compared the slow release of antibiotic in vitro as well as osteoconduction of the material in vivo to a commercially produced porous hydroxyapatite cylinder (HA‐B). HA‐A (4 × 4 mm) was synthesized by mixing HA powder, gelatin, and vegetable oil. The material had a bimodal pore size distribution, with intragranular (10 nm to 10 μm) and intergranular (100 μm) pores, and porosity of 40 vol %, while HA‐B had pore sizes ranging from 50 to 300 μm and identical porosity. In vitro drug release was tested using antibiotics (isepamicin sulfate, vancomycin hydrochloride, and flomoxef sodium) soaked on the HA cylinders using a vacuum system. The mean adsorption efficiency was higher for HA‐A (46%) than for HA‐B (26%) and higher levels of antibiotic were released from HA‐A. Of the antibiotics, ISP showed the longest release duration. Bone ingrowth into the pores was observed for both materials. Because the novel HA showed both the slower release of antibiotic (nanosize pores) and supported excellent osteoconduction (microsize pores), it could be useful for the treatment of osteomyelitis. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 332–339, 2004
3D microtomographic characterization of precision extruded poly‐ϵ‐caprolactone scaffolds
Authors: Darling A. L. , Sun W.
Published: April 2004

One of the dominant approaches to tissue engineering is the seeding of biodegradable, biocompatible polymer scaffolds with progenitor cells prior to 3D culture or implantation. The microarchitecture of these scaffolds has direct effects upon the ability of cells to attach, migrate, and differentiate. Microtomographic (micro‐CT) scanners enable high‐speed 3D characterization of the salient features of these polymer scaffolds. A micro‐CT scan followed by 3D reconstruction of serial image sections can determine porosity, pore size, pore interconnectivity, strut size, and overall 3D microarchitecture. In this study, four polymer samples with different microarchitectures were manufactured through precision extrusion deposition free‐form fabrication and subsequently characterized through micro‐CT analysis. A desktop micro‐CT scanner was used to examine each sample at approximately 19.1‐micron resolution. 2D analyses and 3D reconstructions of core regions of each sample were performed. These results illustrate that qualitative and quantitative analysis of polymer scaffolds is possible using micro‐CT and 3D reconstruction techniques. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 70B: 311–317, 2004
Tissue‐specific regulation of leptin expression and secretion by all‐trans retinoic acid
Authors: Hollung Kristin , Rise Cecilie P. , Drevon Christian A. , Reseland Janne E.
Published: April 2004

In addition to hormones and the sympathetic nervous system, specific nutrients may regulate leptin mRNA expression and adipose tissue metabolism. However, little is known regarding the effect of nutrients on leptin mRNA expression. Retinoic acid (RA) is a ligand of some nuclear receptors and previous reports have demonstrated contradictive effects on plasma leptin levels. Thus, we examined the effect of RA on expression of leptin in adipocytes of murine and human origin. After 48 h incubation of murine 3T3‐L1 adipocytes with 1 and 10 μM all‐trans RA, the expression of leptin mRNA was reduced by 56% and 65%, respectively, whereas the secretion of leptin was reduced by 38% and 77%, respectively. In human adipose tissue explants, 1 μM all‐trans RA reduced leptin mRNA expression levels by 55% and leptin secretion by 25% after 24 h incubation. We observed an increased mRNA expression level of the transcription factors peroxisomal proliferator activated receptor γ (PPARγ), retinoid X receptor α (RXRα), and RA receptor α (RARα) in 3T3‐L1 cells, whereas the mRNA level of these transcription factors was unchanged in human adipose tissue explants after incubation with RA. In two other leptin‐expressing cell systems, the human placental throphoblast cell line BeWo and normal human primary osteoblasts, there was no effect of RA on leptin mRNA expression, but leptin secretion was reduced by 64% after 24 h incubation with 10 μM all‐trans RA in BeWo cells. In conclusion, all‐trans RA reduced both expression and secretion of leptin in human and rodent adipose tissue. In human BeWo cells or primary osteoblasts, leptin mRNA expression levels was not changed by all‐trans RA, indicating a tissue‐specific regulation of leptin mRNA expression by all‐trans RA. © 2004 Wiley‐Liss, Inc.
5‐azacytidine alters TGF‐β and BMP signaling and induces maturation in articular chondrocytes
Authors: Zuscik Michael J. , Baden Jonathan F. , Wu Qiuqian , Sheu Tzong J. , Schwarz Edward M. , Drissi Hicham , O'Keefe Regis J. , Puzas J. Edward , Rosier Randy N.
Published: April 2004

Maintenance of the articular surface depends on the function of articular chondrocytes (ACs) which produce matrix and are constrained from undergoing the maturation program seen in growth plate chondrocytes. Only during pathologic conditions, such as in osteoarthritis, are maturational constraints lost causing recapitulation of the process that occurs during endochondral ossification. With the aim of establishing a model to identify regulatory mechanisms that suppress AC hypertrophy, we examined the capability of 5‐azacytidine (Aza) to have an impact on the maturational program of these cells. Primary ACs do not spontaneously express markers of maturation and are refractory to treatment by factors that normally regulate chondrocyte maturation. However, following exposure to Aza, ACs (i) were induced to express type X collagen (colX), Indian hedgehog, and alkaline phosphatase and (ii) showed altered colX and AP expression in response to bone morphogenetic protein‐2 (BMP‐2), transforming growth factor‐β (TGF‐β), and parathyroid hormone‐related protein (PTHrP). Since Aza unmasked responsiveness of ACs to BMP‐2 and TGF‐β, we examined the effect of Aza treatment on signaling via these pathways by assessing the expression of the TGF‐β Smads (2 and 3), the BMP‐2 Smads (1 and 5), and the Smad2 and 3‐degrading ubiquitin E3 ligase Smurf2. Aza‐treated ACs displayed less Smad2 and 3 and increased Smad1, 5, and Smurf2 protein and showed a loss of TGF‐β signaling on the P3TP‐luciferase reporter. Suggesting that Aza‐induction of Smurf2 may be responsible for the loss of Smad2 and 3 protein via this pathway, immunoprecipitation and metabolic labeling experiments confirmed that Aza accelerated the ubiquitination and degradation of these targets. Overall, Aza‐treated ACs represent a novel model for the study of mechanisms that regulate maturational potential of articular cartilage, with the data suggesting that maturation of these cells may be due to up‐regulation of Smad1 and 5 coupled with a Smurf2‐dependent degradation of Smad2 and 3 and loss of TGF‐β signaling. © 2004 Wiley‐Liss, Inc.
Regulation of neuroinflammation: The role of CXCL10 in lymphocyte infiltration during autoimmune encephalomyelitis
Authors: Klein Robyn S.
Published: April 2004

The movement of lymphocytes from the microvasculature into the central nervous system (CNS) parenchyma is an essential step in the pathogenesis of a variety of infectious and autoimmune neuroinflammatory diseases. The lymphocyte chemoattractant CXCL10 and its receptor, CXCR3, are expressed by the CNS and by CNS infiltrating lymphocytes, respectively, only in patients with ongoing CNS inflammation, suggesting an important role for these molecules in the pathogenic process. Numerous studies utilizing animal models and transgenic approaches have indeed supported a role for CXCL10 in the intraparenchymal trafficking of lymphocytes during acute CNS inflammation; however, other studies suggest that its expression is not required for the development of autoimmune forms of CNS inflammation and, in fact, that interference with CXCL10 signaling could lead to increased neuroinflammation. This review will consider the data from these studies and attempt to reconcile them through comparisons of both the neuroinflammatory models and the effects of CXCL10 in the CNS versus lymphoid tissues. Finally, it will define directions for future analyses of CXCL10 and CXCR3 in CNS inflammation so that their potential therapeutic utility can be more completely determined. © 2004 Wiley‐Liss, Inc.
Overexpression of regucalcin suppresses cell death in cloned rat hepatoma H4‐II‐E cells induced by tumor necrosis factor‐α or thapsigargin
Authors: Izumi Takako , Yamaguchi Masayoshi
Published: April 2004

The role of regucalcin, which is a regulatory protein in intracellular signaling pathway, in the regulation of cell death was investigated by using the cloned rat hepatoma H4‐II‐E cells overexpressing regucalcin. The hepatoma cells (wild‐type) and stable regucalcin (RC)/pCXN2 transfectants were cultured for 72 h in medium containing 10% fetal bovine serum (FBS) to obtain subconfluent monolayers. The proliferation of the cells was significantly suppressed in transfectants cultured for 72 h, as shown previously (Tsurusaki and Yamaguchi [2003]: J Cell Biochem 90:619–626). After culture for 72 h, cells were further cultured for 24–72 h in medium without FBS containing either vehicle, tumor necrosis factor‐α (TNF‐α; 0.1, 1, or 10 ng/ml) or thapsigargin (10−7–10−5 M). The number of wild‐type cells was significantly decreased by culture for 42 or 72 h in the presence of TNF‐α (0.1, 1, or 10 ng/ml) or thapsigargin (10−7–10−5 M). The effect of TNF‐α (0.1 or 1 ng/ml) or thapsigargin (10−7 or 10−6 M) in decreasing the number of hepatoma cells was significantly prevented in transfectants overexpressing regucalcin. The presence of TNF‐α (10 ng/ml) or thapsigargin (10−5 M) caused a significant decrease in cell number of transfectants. Ca2+/calmodulin‐dependent nitric oxide (NO) synthase activity in wild‐type cells was significantly increased by culture with TNF‐α (10 ng/ml) for 48 or 72 h. This increase was significantly prevented in transfectants. Culture with thapsigargin (10−5 M) caused a significant increase in Ca2+/calmodulin‐dependent NO synthase activity in wild‐type cells or transfectants. TNF‐α‐induced decrease in the number of wild‐type cells was significantly prevented by culture with Nω‐nitro‐l‐arginine (10−4 M), an inhibitor of caspase. Agarose gel electrophoresis showed the presence of low‐molecular‐weight deoxyribonucleic acid (DNA) fragments of adherent wild‐type cells cultured with thapsigargin (10−6 M), and this DNA fragmentation was not suppressed by culture with caspase inhibitor. Thapsigargin‐induced DNA fragmentation was significantly suppressed in transfectants cultured with or without caspase inhibitor. This study demonstrates that overexpression of regucalcin has a suppressive effect on cell death induced by TNF‐α or thapsigargin. © 2004 Wiley‐Liss, Inc.
Flavonoid quercetin decreases osteoclastic differentiation induced by RANKL via a mechanism involving NFκB and AP‐1
Authors: Wattel Alice , Kamel Said , Prouillet Christophe , Petit Jean‐Pierre , Lorget Florence , Offord Elizabeth , Brazier Michel
Published: April 2004

Flavonoids are micronutrients widely present in food of plant origin. They have been attributed pharmacological properties such as anticancer and prevention of age‐related pathologies. It has been recently hypothesized that flavonoids increase bone mass and prevent osteoporosis. However, little is known about the in vitro effects of flavonoids on osteoclast activities. We investigated the effects of quercetin, one of the most commonly occurring flavonoids, on osteoclast differentiation which is a critical determinant step of in vivo bone resorption. Two in vitro models of osteoclast differentiation were used in this study: a murine one, involving the culture of RAW 264.7 cells in presence of receptor activator of NFκB ligand (RANKL), and a human model consisting of differentiating peripheral blood monocytic cells (PBMC) isolated from peripheral blood in presence of RANKL and macrophage‐colony stimulating factor (M‐CSF). Osteoclastogenesis was assessed by osteoclast‐like number, tartrate resistant acid phosphatase (TRAP) activity, and bone resorbing activity. We showed that quercetin (0.1–10 μM) decreased osteoclastogenesis in a dose dependent manner in both models with significant effects observed at low concentrations, from 1 to 5 μM. The IC50 value was about 1 μM. Analysis of protein–DNA interaction by electrophoretic mobility shift assay (EMSA) performed on RAW cells showed that a pre‐treatment with quercetin inhibited RANKL‐induced nuclear factor kB (NFκB) and activator protein 1 (AP‐1) activation. NFκB and AP‐1 are transcription factors highly involved in osteoclastic differentiation and their inhibition could play an important role in the decrease of osteoclastogenesis observed in the presence of quercetin. In conclusion, the present results demonstrate for the first time that quercetin, a flavonoid characterized by antioxidant activities, is a potent inhibitor of in vitro osteoclastic differentiation, via a mechanism involving NFκB and AP‐1. © 2004 Wiley‐Liss, Inc.
Therapist affirmation and the process and outcome of psychotherapy: Two sequential analytic studies
Authors: Karpiak Christie P. , Benjamin Lorna Smith
Published: April 2004

Therapist affirmation was examined in two studies, the first with cognitive‐behavioral therapy (CBT, N = 22) and the second with time‐limited dynamic psychotherapy (TLDP, N = 20). Affirmation was identified using Structural Analysis of Social Behavior (SASB), and sequential analysis used to gauge its impact on therapy process and outcome. It was hypothesized that affirmation would correspond with patients' continuation of the current topic of conversation, but relate negatively to outcome if generally offered after maladaptive statements. Patients in Study 1 (CBT) were more likely to continue a topic after it was affirmed, and affirmation of maladaptive statements reliably differentiated patients who evidenced clinically significant change from those who did not at termination and at 12‐months posttreatment. Affirmation of maladaptive statements in Study 2 (TLDP) corresponded with poorer outcome in relationships with significant others, but unexpectedly with improvements in self‐concept. © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Psychological mindedness and cognitive style
Authors: Beitel Mark , Ferrer Elena , Cecero John J.
Published: April 2004

Psychological mindedness (PM) is theorized to be a cognitively toned personality variable, yet, there is a paucity of research addressing the cognitive components of PM. This study was intended to redress this issue by testing the empirical associations between PM and Ambiguity Tolerance, as measured by the Revised Scale for Ambiguity Tolerance (MacDonald, 1970); Locus of Control, as measured by the Locus of Control Scale (Rotter, 1966); and Magical Thinking, as measured by the Magical Ideation Scale (Eckblad & Chapman, 1983). The results indicated that PM is positively associated with ambiguity tolerance, whereas it is inversely related to external locus of control and magical thinking. These findings suggest a cognitive style profile for PM that includes flexibility, a sense of personal agency, and a propensity for realistic thinking. High‐PM individuals are likely to bring these cognitive resources to bear in psychotherapy, a tendency that might explain why high PM patients make better use of treatment. © 2004 Wiley Periodicals, Inc. J Clin Psychol.
Microencapsulation of tannase by chitosan–alginate complex coacervate membrane: synthesis of antioxidant propyl gallate in biphasic media
Authors: Yu Xiaowei , Li Yongquan , Wu Dan
Published: April 2004

Tannase microencapsulated by a chitosan–alginate complex coacervate membrane has been used for synthesis of the food additive antioxidant, propyl gallate. Matrix experiments using standard L9 orthogonal array were used to evaluate the effects of the microencapsulation process on the synthesis of propyl gallate in biphasic media. The statistical analysis of signal‐to‐noise ratio and decomposition of variance (ANOVA) were performed to estimate the optimum levels and determine the relative magnitude of the effects of the three control factors which were chitosan, alginate and hardening time. The optimized capsule for synthesis was formed by dropwise addition of a 15 kg m−3 chitosan and 20 kg m−3 CaCl2 solution into a 14 kg m−3 alginate solution, stirred for 20 min, then hardened for 30 min in 20 kg m−3 CaCl2. Copyright © 2004 Society of Chemical Industry
Enhanced bioremediation of crude oil‐contaminated soil by a Pseudomonas species and mutually associated adapted Azotobacter vinelandii
Authors: Onwurah Ikechukwu NE , Nwuke Chinedu
Published: April 2004

A mixed culture of compatible hydrocarbonoclastic and diazotrophic bacteria, each at a density of 108 organisms cm−3, was developed for optimised bioremediation of crude oil‐contaminated soil. The hydrocarbonoclastic bacterium, Pseudomonas sp and the diazotroph, Azotobacter vinelandii, were both isolated from a previously crude oil‐contaminated soil and thereafter modelled as a unit of mutualistic consortium in situ. Stabilisation of the consortium and hence the optimised bioremediation process occurred when the bacterial growth attained a pseudo‐steady state condition. This was considered to be as a result of a symbiotic association between A vinelandii and the Pseudomonas sp in which A vinelandii produced the required concentration of fixed nitrogen compounds required for the growth of the Pseudomonas sp. Enhancement in biodegradation, due to stimulated growth of Pseudomonas sp and co‐metabolic activity of A vinelandii, was mathematically evaluated as the difference in the specific growth rates (µ) between the consortium Pseudomonas sp/A vinelandii and Pseudomonas sp alone. The proportion of petroleum hydrocarbons degraded by the consortium from the contaminated soil ranged between 66.83 and 69.6% as compared with that of a pure culture of Pseudomonas sp (23.2–44.45%). Hence, beyond their role in biological nitrogen fixation, diazotrophs may be used to contribute to bioremediation of crude oil‐contaminated land. Copyright © 2004 Society of Chemical Industry
Formaldehyde biodegradation and its inhibitory effect on nitrification
Authors: Eiroa Marta , Kennes Christian , Veiga María C
Published: April 2004

The simultaneous removal of formaldehyde and ammonium in aerobic cultures and the inhibitory effect of formaldehyde on ammonium oxidation were investigated. The influence of a co‐substrate, methanol, on formaldehyde biodegradation and on the nitrification process was also evaluated. Formaldehyde was completely removed at all concentrations tested (30–3890 mg dm−3) in assays with that compound as the single carbon source and in the presence of methanol as co‐substrate. An initial formaldehyde biodegradation rate of 4.6 g CH2O g−1 VSS d−1 was obtained for 2000 mg CH2O dm−3 as single carbon source compared with a rate of 7.3 g CH2O g−1 VSS d−1 when methanol was added. Formaldehyde was inhibitory to the nitrification process at initial concentrations higher than 350 mg dm−3. Increasing the initial formaldehyde concentration or adding a co‐substrate such as methanol resulted in a longer lag phase before ammonium oxidation and caused a decrease in the degree of nitrification. Nitrification was completely inhibited at initial formaldehyde concentrations higher than 1500 mg dm−3. Copyright © 2004 Society of Chemical Industry
Exploring process options to enhance metal dissolution in bioleaching of Indian Ocean nodules
Authors: Mukherjee Amitava , Raichur Ashok M , Modak Jayant M , Natarajan KA
Published: April 2004

Polymetallic Indian Ocean nodules offer a lucrative resource for valuable strategic metals such as Cu, Co and Ni. A novel bioleaching process using cell‐free spent growth medium from a fully‐grown culture of a marine organism isolated from the nodules (Bacillus M1) dissolved about 45% Co, and 25% Cu and Ni at a the pH of 8.2 in 4 h. To enhance metal dissolution, different modifications in the bioleaching process, such as increasing the pH of the spent growth medium, carrying out leaching in multiple steps, and introducing organic reductant in the leach pulp, were investigated in this study. Increasing the initial pH of the spent growth medium to above 12 resulted in a 25–30% increase in dissolution of Cu, Co and Ni. The pKa value for the spent growth medium was observed to be in the range of 11.5–12.5. UV‐visible spectroscopy of the growth medium at pH values above 10.0 suggested a change in the structure of complexing phenolic substances present therein. A four‐step leaching process using the spent growth medium, each step lasting for about 4 h, was able to bring around 60% Cu and Ni and 85% Co in solution. About 85% Co, 90% Cu and 60% Ni were dissolved in two‐stage leaching, in which the bioleached residue was treated with the spent growth medium from Acidithiobacillus thiooxidans in the second cycle. The effects of concentration of starch (0.1–10%) as an organic reductant to the spent growth medium were also studied. The dissolution of Cu, Co and Ni stabilized at about 80–85% at a starch concentration of 3% and did not increase much thereafter. Copyright © 2004 Society of Chemical Industry
Kinetics of fluid–solid reaction with an insoluble product: zinc borate by the reaction of boric acid and zinc oxide
Authors: Shete Aparna V , Sawant Sudhir B , Pangarkar Vishwas G
Published: April 2004

Mixing parameters influencing the final particle size and conversion of zinc oxide were studied for the formation of zinc borate. Formation of zinc borate was via a fluid–solid reaction. The process was kinetically controlled above the minimum speed for particle suspension, Ns. The reaction kinetics was developed and the rate constant was estimated. Copyright © 2004 Society of Chemical Industry