bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of high glucose on gene expression in mesangial cells: upregulation of the thiol pathway is an adaptational response
Authors: Morrison Jolean , Knoll Kristen , Hessner Martin J. , Liang Mingyu
Published: March 2004

Pathological alterations in glomerular mesangial cells play a critical role in the development of diabetic nephropathy, the leading cause of end-stage renal disease. Molecular mechanisms mediating such alterations, however, remain to be fully understood. The present study first examined the effect of high glucose on the mRNA expression profile in rat mesangial cells using cDNA microarray. Based on variation-weighted criteria and with a false discovery rate of 4.3%, 459 of 17,664 cDNA elements examined were found to be upregulated and 151 downregulated by exposure to 25 mM d-glucose for 5 days. A large number of differentially expressed genes belonged to several functional categories, indicating high glucose had a profound effect on mesangial cell proliferation, protein synthesis, energy metabolism, and, somewhat unexpectedly, protein sorting and the cytoskeleton. Interestingly, several thiol antioxidative genes (glutathione peroxidase 1, peroxiredoxin 6, and thioredoxin 2) were found by microarray and confirmed by real-time PCR to be upregulated by high glucose. These changes suggested that the oxidative stress known to be induced in mesangial cells by high glucose might be buffered by upregulation of the thiol antioxidative pathway. Upregulation of thiol antioxidative genes also occurred in high-glucose-treated human mesangial cells and in glomeruli isolated from rats after 1 wk of streptozotocin-induced diabetes, but not in human proximal tubule cells. High glucose slightly increased lipid peroxidation and decreased the amount of reduced thiols in rat and human mesangial cells. Disruption of the thiol antioxidative pathway by two different thiol-oxidizing agents resulted in a three- to fivefold increase in high-glucose-induced lipid peroxidation. In summary, the present study provided a global view of the short-term effect of high glucose on mesangial cells at the level of mRNA expression and identified the upregulation of the thiol antioxidative pathway as an adaptational response of mesangial cells to high glucose.
Additive regulation of hepatic gene expression by dwarfism and caloric restriction
Authors: Tsuchiya Tomoshi , Dhahbi Joseph M. , Cui Xinping , Mote Patricia L. , Bartke Andrzej , Spindler Stephen R.
Published: March 2004

Disrupted growth hormone/insulin-like growth factor-1 signaling (DF) and caloric restriction (CR) extend life span and delay the onset of age-related diseases in rodents. In combination, these interventions additively extend life span. To investigate the molecular basis for these effects, we performed genome-wide, microarray expression analysis of liver from homozygous and heterozygous Ames dwarf mice fed ad libitum or CR. CR and DF additively affected a group of 95 genes. Individually and together, DF and CR independently affected the expression of 212 and 77 genes, respectively. These results indicate that DF and CR affect overlapping sets of genes and additively affect a subset of genes. Together, the interventions produced changes in gene expression consistent with increased insulin, glucagon and catecholamine sensitivity, gluconeogenesis, protein turnover, lipid β-oxidation, apoptosis, and xenobiotic and oxidant metabolism; and decreased cell proliferation, lipid and cholesterol synthesis, and chaperone expression. These data suggest that the additive effects of DF and CR on life span develop from their additive effects on the level of expression of some genes and from their independent effects on other genes. These results provide a novel and focused group of genes closely associated with the regulation of life span in mammals.
NF1 Regulatory Element Functions as a Repressor of Tissue Plasminogen Activator Expression
Authors: Pham Nhat-Long , Franzen Amy , Levin Eugene G.
Published: March 2004

Objective—

Analysis of the distribution of endothelial cell tissue plasminogen activator (tPA) in the vasculature of rodents and primates demonstrated that tPA is constitutively expressed predominately in small artery endothelial cells of brain and lung. The regulatory elements responsible for the highly selective expression of arterial endothelial cell tissue plasminogen activator were sought.

Methods and Results—

Transcription factor binding sites were defined by electrophoretic mobility-shift assay (EMSA) analysis using rat lung and brain nuclear extracts and the tPA promoter sequence from −609 to +37 bp. Protein binding to the promoter was found to be mediated by an NF1 site between −158 and −145 bp upstream from the transcriptional start site. Specific binding was confirmed through mutational analysis and competition binding studies. Infection of endothelial cells with a tPA promoter-green fluorescent protein (GFP) (−609 to +37 bp) reporter construct resulted in expression of the GFP, whereas no expression was found in smooth muscle cells. Mutation of the NF1 site increased the GFP expression indicating that the element acts as a repressor.

Conclusions—

These results suggest that the 600 bp of the tPA promoter upstream of the transcription start site conveys cell specificity to tPA expression and that an NF1 site within this region acts as a repressor.
Conformational Rearrangement in C-Reactive Protein Is Required for Proinflammatory Actions on Human Endothelial Cells
Authors: Khreiss Tarek , József Levente , Potempa Lawrence A. , Filep János G.
Published: March 2004

Background—

C-reactive protein (CRP) has been suggested to actively amplify the inflammatory response underlying coronary heart diseases by directly activating endothelial cells. In this study, we investigated whether loss of the cyclic pentameric structure of CRP, resulting in formation of modified or monomeric CRP (mCRP), is a prerequisite for endothelial cell activation.

Methods and Results—

We examined the impact of native CRP and mCRP on the production of monocyte chemoattractant protein-1 (MCP-1) and interleukin-8 (IL-8), key regulators of leukocyte recruitment, and on the expression of intercellular adhesion molecule-1 (ICAM-1), E-selectin, and vascular adhesion molecule-1 (VCAM-1) in human cultured coronary artery endothelial cells (HCAECs). Incubation with mCRP for 4 hours increased MCP-1 and IL-8 secretion and mRNA levels and expression of ICAM-1, E-selectin, and VCAM-1 protein and mRNA. Significant induction occurred at 1 to 5 μg/mL, reached a maximum at 30 μg/mL, and did not require the presence of serum. Native CRP was without detectable effects at 4 hours, whereas it enhanced cytokine release after a 24-hour incubation. An anti-FcγRIII (CD16) but not an anti-FcγRII (CD32) antibody produced a 14% to 32% reduction of the mCRP effects (
P
<0.05). mCRP but not CRP evoked phosphorylation of p38 mitogen-activated protein kinase, and inhibition of this kinase with SB 203580 reversed the effects of mCRP. Furthermore, culture of HCAECs in the presence of SB203580 markedly decreased mCRP-stimulated E-selectin and ICAM-1–dependent adhesion of neutrophils to HCAECs (
P
<0.001).

Conclusions—

Loss of pentameric symmetry in CRP, resulting in formation of mCRP, promotes a proinflammatory HCAEC phenotype through a p38 MAPK–dependent mechanism.
Clonidine Improves Spontaneous Baroreflex Sensitivity in Conscious Mice Through Parasympathetic Activation
Authors: Tank Jens , Jordan Jens , Diedrich André , Obst Michael , Plehm Ralph , Luft Friedrich C. , Gross Volkmar
Published: March 2004

α-2 Adrenoceptors are important in baroreflex regulation. We tested the impact of α-2 adrenoceptors on heart rate variability (HRV) and spontaneous baroreflex sensitivity (BRS) in conscious mice with telemetry (TA11PA-C20). Baseline beat-to-beat measurements (2 hours between 8:00
am
to 12:00
pm
) were compared with measurements after intraperitoneal α-2 adrenoceptor blockade (yohimbine 2 mg/kg) and α-2 adrenoceptor stimulation (clonidine 1, 10, and 50 mg/kg). Blood pressure (BP) was 128±6/87±6 mm Hg and heart rate (HR) was 548±18 bpm at baseline. BRS, calculated with the cross-spectral method, was 1.2±0.1 ms/mm Hg at baseline. BP increased 20±2/13±2 mm Hg with yohimbine. HR increased by 158±23 bpm. BRS did not change. BP decreased 16±7/5±4 mm Hg with 1 mg/kg of clonidine and did not change with a higher dose. HR decreased with clonidine (176±28, 351±21, 310±29 bpm during 1, 10, and 50 mg/kg of clonidine,
P
<0.01). HRV (total power=4629±465, 7002±440, and 6452±341 ms
2
during 1, 10, and 50 mg/kg of clonidine,
P
<0.01) and BRS were profoundly increased with clonidine (14±1, 13±1, and 10±1 ms/mm Hg,
P
<0.01). The effects of clonidine were abolished with atropine (2 mg/kg plus 50 mg/kg of clonidine) but not with metoprolol (4 mg/kg plus 50 mg/kg of clonidine). These data suggest that α-2 adrenoceptors exert a regulatory influence on autonomic cardiovascular control and baroreflex function. The effect of clonidine on baroreflex HR regulation is mediated by the parasympathetic nervous system. These murine data fit well with recent human observations regarding parasympathetic activation via α-2 adrenoceptors.
SM22α Modulates Vascular Smooth Muscle Cell Phenotype During Atherogenesis
Authors: Feil Susanne , Hofmann Franz , Feil Robert
Published: March 2004

The function of cytoskeletal proteins in the modulation of vascular smooth muscle cell (SMC) phenotype during vascular disease is poorly understood. In this report, we used a combination of gene targeting and Cre/lox-mediated cell fate mapping in mice to investigate the role of SM22α, an SMC-specific cytoskeletal protein of unknown function, in the development of atherosclerosis. In hypercholesterolemic ApoE-deficient mice, genetic ablation of SM22α resulted in increased atherosclerotic lesion area and a higher proportion of proliferating SMC-derived plaque cells. These results identify a role for SM22α in the regulation of SMC phenotype during atherogenesis.
New approach for bone marrow transplantation in patients with class 3 thalassemia aged younger than 17 years
Authors: Sodani Pietro , Gaziev David , Polchi Paola , Erer Buket , Giardini Claudio , Angelucci Emanuele , Baronciani Donatella , Andreani Marco , Manna Marisa , Nesci Sonia , Lucarelli Barbarella , Clift Reginald A. , Lucarelli Guido
Published: March 2004

When prepared for transplantation with busulfan (BU) 14 mg/kg and cyclophosphamide (CY) 120 to 160 mg/kg, patients with thalassemia in risk class 3, aged younger than 17 years, who receive transplants from HLA-identical donors, had a 30% incidence of transplant rejection with recurrence of thalassemia. This, relatively poor, outcome was ascribed to insufficient immune suppression or to inadequate eradication of the thalassemic marrow, or both. In an attempt to enhance both immune suppression and eradication of the thalassemic clones, hydroxyurea, azathioprine, and fludarabine were added to the BU and CY. This regimen, called protocol 26, was applied to 33 consecutive patients with class 3 thalassemia aged younger than 17 years and was well tolerated with 93% survival. The incidence of recurrent thalassemia after the transplantation decreased from 30% to 8%. (Blood. 2004;104:1201-1203)
Bone marrow transplantation restores immune system function and prevents lymphoma in Atm-deficient mice
Authors: Bagley Jessamyn , Cortes Maria L. , Breakefield Xandra O. , Iacomini John
Published: March 2004

Ataxia-telangiectasia (A-T) is a human autosomal recessive disease caused by mutations in the gene encoding ataxia-telangiectasia mutated (ATM). A-T is characterized by progressive cerebellar degeneration, variable immunodeficiency, and a high incidence of leukemia and lymphoma. Recurrent sino-pulmonary infections secondary to immunodeficiency and hematopoietic malignancies are major causes of morbidity and mortality in A-T patients. In mice, an introduced mutation in Atm leads to a phenotype that recapitulates many of the symptoms of A-T, including immune system abnormalities and susceptibility to malignancy. Here we show that the replacement of the bone marrow compartment in Atm knockout mice (Atm-/-) using a clinically relevant, nonmyeloablative host-conditioning regimen can be used to overcome the immune deficiencies and prevent the malignancies observed in these mice. Therefore, bone marrow transplantation may prove to be of therapeutic benefit in A-T patients. (Blood. 2004;104:572-578)
A recombinant murine meizothrombin precursor, prothrombin R157A/R268A, inhibits thrombosis in a model of acute carotid artery injury
Authors: Shim Kyuhwan , Zhu Hongfa , Westfield Lisa A. , Sadler J. Evan
Published: March 2004

Mutations in human prothrombin that generate a stable form of meizothrombin or meizothrombin(desF1) cause dysprothrombinemia in both the homozygous and heterozygous state, suggesting that meizothrombin has dominant anticoagulant effects in vivo. The enzymatic characterization of recombinant mouse meizothrombin, meizothrombin(desF1), and thrombin indicates that all 3 enzymes have similar activity toward the chromogenic substrate S-2238, that meizothrombin and meizothrombin(desF1) have less than 10% of the fibrinogen-clotting activity of thrombin, and that meizothrombin is more active than thrombin or meizothrombin(desF1) for thrombomodulin-dependent protein C activation. Thus, activated mouse prothrombin R157A/R268A is similar to human meizothrombin in activity toward S-2238, fibrinogen, and protein C. The time to occlusion after FeCl3-induced carotid artery injury was delayed (11.8 ± 3.6 minutes, n = 5) in Cf2+/- mice infused with prothrombin R157A/R268A compared with control mice infused with wild-type prothrombin (5.3 ± 1.5 minutes, n = 3; P = .006). In this model, prothrombin R157A/R268A has anticoagulant activity that reflects its decreased fibrinogen-clotting activity and preserved protein C-activating activity and is consistent with dominant inhibition of fibrinogen clotting. (Blood. 2004;104:415-419)
Aging and innate immune cells
Authors: Plackett Timothy P , Boehmer Eric D , Faunce Douglas E , Kovacs Elizabeth J
Published: March 2004

The innate immune system serves an important role in preventing microbial invasion. However, it experiences significant changes with advancing age. Among the age-associated changes are: Aged macrophages and neutrophils have impaired respiratory burst and reactive nitrogen intermediates as a result of altered intracellular signaling, rendering them less able to destroy bacteria. Aged neutrophils are also less able to respond to rescue from apoptosis. Aged dendritic cells (DC) are less able to stimulate T and B cells. The altered T cell stimulation is a result of changes in human leukocyte antigen expression and cytokine production, and lower B cell stimulation is a result of changes in DC immune complex binding. Natural killer (NK) cells from the elderly are less capable of destroying tumor cells. NK T cells increase in number and have greater interleukin-4 production with age. Levels of various complement components are also altered with advancing age.
Virus-Directed Enzyme Prodrug Therapy: Intratumoral Administration of a Replication-Deficient Adenovirus Encoding Nitroreductase to Patients With Resectable Liver Cancer
Authors: Palmer Daniel H. , Mautner Vivien , Mirza Darius , Oliff Simon , Gerritsen Winald , van der Sijp Joost R.M. , Hubscher Stefan , Reynolds Gary , Bonney Sarah , Rajaratnam Ratna , Hull Diana , Horne Mark , Ellis John , Mountain Andrew , Hill Simon , Harris Peter A. , Searle Peter F. , Young Lawrence S. , James Nicholas D. , Kerr David J.
Published: March 2004

Purpose

Virus-directed enzyme prodrug therapy depends on selective delivery of virus encoding a prodrug-activating enzyme to tumor, followed by systemic treatment with prodrug to achieve high levels of the activated cytotoxic at the intended site of action. The use of the bacterial enzyme nitroreductase to activate CB1954 (5-(aziridin-1-yl)-2,4-dinitrobenzamide) to a short lived, highly toxic DNA cross-linking agent has been demonstrated in tumor xenografts. In this study, we report the first clinical trial investigating the feasibility, safety, and transgene expression of a replication-defective adenovirus encoding nitroreductase (CTL102) in patients with liver tumors.

Patients and Methods

Patients with resectable primary or secondary (colorectal) liver cancer received a single dose of CTL102 delivered by direct intratumoral inoculation 3 to 8 days before surgical resection.

Results

Eighteen patients were treated with escalating doses of CTL102 (range, 108–5 × 1011 virus particles). The vector was well tolerated with minimal side effects, had a short half-life in the circulation, and stimulated a robust antibody response. Dose-related increases in tumoral nitroreductase expression measured by immunohistochemical analysis have been observed.

Conclusion

Direct intratumoral inoculation of CTL102 to patients with primary and secondary liver cancer is feasible and well tolerated. The high level of nitroreductase expression observed at 1 to 5 × 1011 virus particles mandates further studies in patients with inoperable tumors who will receive CTL102 and CB1954.
Mechanisms Underlying Growth Hormone Effects in Augmenting Nitric Oxide Production and Protein Tyrosine Nitration during Endotoxin Challenge
Authors: Elsasser Ted H. , Kahl Stanislaw , MacLeod Carol , Nicholson Benjamin , Sartin James L. , Li Congjun
Published: March 2004

The present study defined the effects of GH administration on components of the nitric oxide (NO)-generating cascade to account for observed increases in NO production and protein nitration after an immune challenge. Calves were assigned to groups with or without GH treatment (100 μg GH/kg body weight or placebo im, daily for 12 d) and with or without low-level endotoxin [lipopolysaccharide (LPS), 2.5 μg/kg, or placebo, iv]. Plasma was obtained for estimation of NO changes as [NO2− + NO3−] (NOx). Transcutaneous liver biopsies were collected for measurement of protein tyrosine nitration, cationic amino acid transporter (CAT)-2 mRNA transporter, and constitutive NO synthase (cNOS), inducible NOS (iNOS), and arginase activity. Liver protein nitration increased more than 10-fold 24 h after LPS and an additional 2-fold in animals treated with GH before LPS. GH increased plasma NOx after LPS to levels 27% greater than those measured in non-GH-treated calves. LPS increased CAT-2 mRNA after LPS; GH was associated with a 24% reduction in CAT-2 mRNA content at the peak time response. cNOS activity was 3-fold greater than iNOS after LPS. NOS activities were increased 140% (cNOS) at 3 h and 169% (iNOS) at 6 h, respectively, after LPS; GH treatment increased cNOS activity and the phosphorylation of endothelial NOS after LPS more than 2-fold over that measured in non-GH-treated calves. The data suggest that an increased production of nitrated protein develops in the liver during low-level, proinflammatory stress, and nitration is increased by GH administration through a direct effect on the competing activities of NOS and arginase, modulatable critical control points in the proinflammatory cascade.
Endothelium-specific ablation of PDGFB leads to pericyte loss and glomerular, cardiac and placental abnormalities
Authors: Bjarnegård Mattias , Enge Maria , Norlin Jenny , Gustafsdottir Sigrun , Fredriksson Simon , Abramsson Alexandra , Takemoto Minoru , Gustafsson Erika , Fässler Reinhard , Betsholtz Christer
Published: March 2004

Platelet-derived growth factor-B (PDGFB) is necessary for normal cardiovascular development, but the relative importance of different cellular sources of PDGFB has not been established. Using Cre-lox techniques, we show here that genetic ablation of Pdgfb in endothelial cells leads to impaired recruitment of pericytes to blood vessels. The endothelium-restricted Pdgfb knockout mutants also developed organ defects including cardiac, placental and renal abnormalities. These defects were similar to those observed in Pdgfb null mice. However, in marked contrast to the embryonic lethality of Pdgfb null mutants, the endothelium-specific mutants survived into adulthood with persistent pathological changes,including brain microhemorrhages, focal astrogliosis, and kidney glomerulus abnormalities. This spectrum of pathological changes is reminiscent of diabetic microangiopathy, suggesting that the endothelium-restricted Pdgfb knockouts may serve as models for some of the pathogenic events of vascular complications to diabetes.
Organ-specific stress induces mouse pancreatic keratin overexpression in association with NF-κB activation
Authors: Zhong Bihui , Zhou Qin , Toivola Diana M. , Tao Guo-Zhong , Resurreccion Evelyn Z. , Omary M. Bishr
Published: March 2004

Keratin polypeptides 8 and 18 (K8/K18) are the major intermediate filament proteins of pancreatic acinar cells and hepatocytes. Pancreatic keratin function is unknown, whereas hepatocyte keratins protect from mechanical and non-mechanical forms of stress. We characterized steady-state pancreatic keratin expression in Balb/c mice after caerulein and choline-deficient ethionine-supplemented diet (CDD), or on exposure to the generalized stresses of heat and water immersion. Keratins were studied at the protein, RNA and organizational levels. Isolated acini were used to study the role of nuclear factor (NF)-κB using selective inhibitors. Keratins were found to be abundant proteins making up 0.2%, 0.3% and 0.5% of the total cellular protein of pancreas, liver and small intestine, respectively. Caerulein and CDD caused a threefold transcription-mediated overall increase in K8/K18/K19/K20 proteins. Keratin overexpression begins on tissue recovery, peaks 2 days after caerulein injection, or 1 day after CDD discontinuation, and returns to basal levels after 10 days. K19/K20-containing cytoplasmic filaments are nearly absent pre-injury but form post-injury then return to their original membrane-proximal distribution after 10 days. By contrast, generalized stresses of heat or water-immersion stress do not alter keratin expression levels. Caerulein-induced keratin overexpression is associated with NF-κB activation when tested using ex vivo acinar cell cultures. In conclusion, keratins are abundant proteins that can behave as stress proteins in response to tissue-specific but not generalized forms of injury. Pancreatic keratin overexpression is associated with NF-κB activation and may serve unique functions in acinar or ductal cell response to injury.
Sister chromatid separation at human telomeric regions
Authors: Yalon Michal , Gal Shoshana , Segev Yardena , Selig Sara , Skorecki Karl L.
Published: March 2004

Telomeres are nucleoprotein complexes located at chromosome ends, vital for preserving chromosomal integrity. Telomeric DNA shortens with progressive rounds of cell division, culminating in replicative senescence. Previously we have reported, on the basis of fluorescent in situ hybridization, that several human telomeric regions display solitary signals (singlets) in metaphase cells of presenescent fibroblasts, in comparison to other genomic regions that hybridize as twin signals (doublets). In the current study, we show that an additional 12 out of 12 telomeric regions examined also display metaphase singlet signals in pre-senescent cells, and that excess telomere-metaphase singlets also occur in earlier passage cells harvested from elderly individuals. In cancer cell lines expressing telomerase and in pre-senescent fibroblasts ectopically expressing hTERT, this phenomenon is abrogated. Confocal microscope image analysis showed that the telomere metaphase singlets represent regions that have replicated but not separated; this is presumably because of persistent cohesion. The introduction of mutations that interfere with the normal dissolution of cohesion at the metaphase to anaphase transition induced the cut (chromosomes untimely torn) phenotype in early passage fibroblasts, with predominantly telomeric rather than centromeric DNA, present on the chromatin bridges between the daughter nuclei. These results suggest that telomeric regions in animal cells may potentially be sites of persistent cohesion, and that this cohesion may be the basis for an observed excess of fluorescent in situ hybridization metaphase singlets at telomeres. Persistent cohesion at telomeres may be associated with attempted DNA repair or chromosomal abnormalities, which have been described in pre-senescent cells.
Secreted MMP9 promotes angiogenesis more efficiently than constitutive active MMP9 bound to the tumor cell surface
Authors: Mira Emilia , Lacalle Rosa Ana , Buesa José María , de Buitrago Gonzalo González , Jiménez-Baranda Sonia , Gómez-Moutón Concepción , Martínez-A Carlos , Mañes Santos
Published: March 2004

Association of matrix metalloprotease 9 (MMP9) to the cell membrane is considered important in tumor growth and angiogenesis. To dissect this regulatory mechanism, we generated raft and non-raft MMP9 chimeras to force membrane expression in the MCF-7 human breast carcinoma cell line. MMP9 targeting to non-raft cell surface domains rendered a constitutive active membrane MMP9 form, suggesting a contribution by the lipid environment in MMP activation. We generated human breast cancer xenograft models using MCF-7 cells overexpressing secreted and membrane-anchored MMP9. The non-raft MMP9 chimera was constitutively active at the cell membrane in xenografts, but this activation did not correlate with an increase in MMP9-induced angiogenesis. Capillary number and vessel perimeter were specifically increased only in tumors overexpressing wild-type MMP9 (the secreted form); this increase was inhibited when tumors were induced in doxycycline-treated mice. Xenografts from tumor cells overexpressing wild-type MMP9 showed increased vascular endothelial growth factor (VEGF)/VEGFR2 receptor association, which was also dependent on MMP9 activity. These observations indicate that membrane location can influence MMP9 activity in vitro and in vivo, and confirm the relevance of stromal-associated, but not tumor-bound MMP9 in mediating tumor-induced angiogenesis.
Myofilament anchoring of protein kinase C-epsilon in cardiac myocytes
Authors: Huang Xupei , Walker Jeffery W.
Published: March 2004

Regulatory proteins on muscle filaments are substrates for protein kinase C (PKC) but mechanisms underlying activation and translocation of PKC to this non-membrane compartment are poorly understood. Here we demonstrate that the epsilon isoform of PKC (ϵ-PKC) activated by arachidonic acid (AA) binds reversibly to cardiac myofibrils with an EC50 of 86 nM. Binding occurred near the Z-lines giving rise to a striated staining pattern. The delta isoform of PKC (δ-PKC) did not bind to cardiac myofibrils regardless of the activator used, and the alpha isoform (α-PKC) bound only under strong activating conditions. Three established PKC anchoring proteins, filamentous actin (F-actin), the LIM domain protein Cypher-1, and the coatamer protein β′-COP were each tested for their involvement in cytoskeletal anchoring. F-actin bound ϵ-PKC selectively over δ-PKC and α-PKC, but this interaction was readily distinguishable from cardiac myofilament binding in two ways. First, the F-actin/ϵ-PKC interaction was independent of PKC activation, and second, the synthetic hexapeptide LKKQET derived from the C1 region of ϵ-PKC effectively blocked ϵ-PKC binding to F-actin, but was without effect on its binding to cardiac myofilaments. Involvement of Cypher-1 was ruled out on the basis of its absence from detergent-skinned myofibrils that bound ϵ-PKC, despite its presence in intact cardiac myocytes. The ϵ-PKC translocation inhibitor peptide EAVSLKPT reduced activated ϵ-PKC binding to cardiac myofibrils in a concentration dependent manner, suggesting that a RACK2 or a similar protein plays a role in ϵ-PKC anchoring in cardiac myofilaments.
Hydrothermal Synthesis and Characterization of Bi2Fe4O9 Nanoparticles
Authors: Xiong Ying , Wu Mingzai , Peng Zhenmeng , Jiang Nan , Chen Qianwang
Published: March 2004

Sheet-like Bi2Fe4O9 nanoparticles were successfully synthesized by a rather facile hydrothermal process. Transmission electron microscopic (TEM) and selected area electron diffraction (SAED) studies show that the particles are sheet-like, about 30 nm in the direction of thickness. X-ray diffraction (XRD) analysis indicated that the as-prepared particles were pure Bi2Fe4O9, but after storing at room temperature for half a year, γ-Fe2O3 appeared. The magnetic properties of the nanoparticles before and after storing were characterized by a vibration sample magnetometer (VSM).
Self-assembly of Poly(aniline-co-anthranilic acid) Copolymers and PVP into Fibers and Other Microstructures
Authors: Lu Xiaofeng , Yu Youhai , Chen Liang , Mao Huaping , Zhang Wanjin , Wei Yen
Published: March 2004

The morphology of the self-assembly of poly(aniline-co-anthranilic acid) copolymers (PAAA) and poly (N-vinypyrrolidone) (PVP) into particles in DMF/H2O solution and fibers in sodium hydroxide solution was studied. Not only the solvent but also the content of PVP affected the morphology significantly. When the content of PVP is zero, no fibers were formed. With the increasing of the content of PVP, more and more fiber junctions appeared.
Report of the FELASA Working Group on evaluation of quality systems for animal units
Authors: Howard B. , van Herck H. , Guillen J. , Bacon B. , Joffe R. , Ritskes-Hoitinga M.
Published: March 2004

This report compares and considers the merits of existing, internationally available quality management systems suitable for implementation in experimental animal facilities. These are: the Good Laboratory Practice Guidelines, ISO 9000:2000 (International Organization for Standardization) and AAALAC International (Association for Assessment and Accreditation of Laboratory Animal Care International). Good laboratory practice (GLP) is a legal requirement for institutions undertaking non-clinical health and environmental studies for the purpose of registering or licensing for use and which have to be 'GLP-compliant'. GLP guidelines are often only relevant for and obtainable by those institutions. ISO is primarily an external business standard, which provides a management tool to master and optimize a business activity; it aims to implement and enhance 'customer satisfaction'. AAALAC is primarily a peer-reviewed system of accreditation which evaluates the organization and procedures in programmes of animal care and use to ensure the appropriate use of animals, safeguard animal well-being (ensuring state-of-the-art housing, management, procedural techniques, etc.) as well as the management of health and safety of staff. Management needs to determine, on the basis of a facility's specific goals, whether benefits would arise from the introduction of a quality system and, if so, which system is most appropriate. The successful introduction of a quality system confers peer-recognition against an independent standard, thereby providing assurance of standards of animal care and use, improving the quality of animal studies, and contributing to the three Rs—reduction, refinement and replacement.
Continuous intra-arterial blood gas monitoring in rats
Authors: Pakulla M. A. , Obal D. , Loer S. A.
Published: March 2004

Studies on lung injury and its treatment options are often performed on small animals like rats. Because conventional blood gas analyses may not detect rapid changes in gas exchange during respiratory distress syndrome and intermittent blood withdrawal can result in hypo-volaemia and anaemia, we tested the applicability and accuracy of a continuous intravascular blood gas monitor (Paratrend 7+). Anaesthetized and ventilated rats with a body weight of 398 ±45 g ( n =22) had a 20-gauge cannula inserted in both carotid arteries. A photochemical blood gas sensor for continuous measurement (Paratrend 7+) was advanced into the aorta via the left carotid artery. Blood was sampled for intermittent blood gas analysis by means of the right carotid artery. Arterial pO2 was varied by applying different inspiratory oxygen concentrations, and arterial pCO2 by applying different respiratory rates. Paired blood gas measurements ( n =136) were analysed over a wide range of pO2 values (5.3-76.8 kPa). We found an acceptable correlation for pO2 ( r2=0.98), pCO2 ( r2=0.96) and pH ( r2=0.92). The calculated bias and imprecision for pO2 was -1.0 ± 3.3 kPa, for pCO2 0.04 ± 0.28 kPa and for hydrogen ion concentration -0.05 ±2.2 nmol/l. We conclude that in rats, continuous blood gas monitoring with a photochemical blood gas sensor provides pO2, pCO2 and pH measurements with acceptable accuracy.
Preference for social contact versus environmental enrichment in male laboratory mice
Authors: Van Loo P. L. P. , Van de Weerd H. A. , Van Zutphen L. F. M. , Baumans V.
Published: March 2004

Due to their aggressive nature, male mice are less frequently used than female mice in biomedical research. When aggressive males are being used, individual housing is common practice. The question arises whether this is an acceptable housing for a social species. The present study was designed to gain more insight into the nature of inter-male social contact and into the potential of a form of environmental enrichment (nesting material) to compensate for the lack of social contact. In a series of tests, we analysed whether male mice of different ages preferred to spend time (1) near a familiar cage mate versus an empty cage, or (2) near to a familiar cage mate versus direct contact with nesting material (tissues). Dwelling time in each of the test cages and sleeping sites was recorded, as was the behaviour of the test mice. Results indicated that when other conditions were similar, male mice preferred to sleep in close proximity to their familiar cage mate. Furthermore, the need to engage in active social behaviour increased with age. Tissues were used to a large extent for sleeping and sleep-related behaviour. It is concluded that single housing in order to avoid aggression between male mice is a solution with evident negative consequences for the animals. When individual housing is inevitable due to excessive aggressive behaviour, the presence of nesting material could partly compensate for the deprivation of social contact.
Herbal Weight-Loss Supplement Misadventures Per a Regional Poison Center
Authors: Robinson Renee F , Griffith Jill R , Nahata Milap C , Mahan John D , Casavant Marcel J
Published: March 2004

BACKGROUND

Many herbal supplements used for weight loss contain stimulants. The poison control center has noted an increase in reports of adverse events with intentional and unintentional ingestion of herbal weight-loss supplements.

OBJECTIVE

To identify characteristics of the callers (eg, demographic properties, underlying type of ingestion) and, from this information, determine populations at increased risk for adverse events secondary to intentional and unintentional herbal weight-loss supplement ingestion.

METHODS

Demographic information such as patient weight, age, gender, and medical history was recorded from ingestions reported to the Central Ohio Poison Control Center (COPC) in 2000. Ingredients, concurrent medications, ingestion and treatment site, clinical presentation, and therapies received were documented. Type of ingestion, acuity, clinical presentation, and treatment site were used to identify patients at increased risk of adverse events secondary to herbal supplement ingestion.

RESULTS

Eighty calls were recorded in 2000 (49 females involved). Underlying reasons for ingestion differed between males and females (p = 0.025). Twenty-five percent of the intentional ingestions and 51% of the unintentional ingestions occurred in males. Reported symptoms differed with the underlying reason for ingestion (p ≤ 0.001) and were more common in intentional ingestions (80%). Symptoms were reported more often with unknown or higher-than-recommended doses (78%); however, 70% (n = 10) of subjects ingesting the recommended dose reported at least one symptom (p = 0.15).

CONCLUSIONS

Intentional and unintentional ingestions of herbal supplements for weight loss vary with age and gender. The significant presence of symptoms in nonabusers requires more study to assess overall safety and potential toxicity of agents such as Stacker 2. Patients who abuse or misuse herbal weight-loss supplements are generally women, who may seek medical treatment more often.
Rate Versus Rhythm Control in Atrial Fibrillation
Authors: Anthony Korin K , Mauro Vincent F
Published: March 2004

OBJECTIVE

To determine whether rate control is a viable initial treatment approach in persistent atrial fibrillation (AF) through the evaluation of recently completed trials comparing rate and rhythm control.

DATA SOURCES

Biomedical literature was obtained through MEDLINE (1966—December 2003) and the Iowa database.

STUDY SELECTION AND DATA EXTRACTION

Articles identified from the biomedical literature search were reviewed and included if deemed relevant.

DATA SYNTHESIS

Currently available data suggest that rate control is not inferior to rhythm control in patients with persistent AF with respect to mortality. Rate control also reduces hospitalizations and the occurrence of proarrhythmias. No significant difference was observed between treatments with respect to thromboembolism and strokes.

CONCLUSIONS

Due to the increased incidence of hospitalizations and antiarrhythmic adverse effects associated with rhythm control, rate control is a reasonable first-line strategy in the treatment of recurrent AF, especially in elderly patients who are asymptomatic or mildly symptomatic. Further studies are needed to clearly define the role of rate control in younger patients.
On the Problem of Sample Preservation by Freezing
Authors: Rinne Dieter , Schmitt Petra
Published: March 2004

During routine analysis of running water samples differences of the analytical results of water‐soluble anions were observed between analysis carried out immediately after sampling and after storage of the cooled/frozen sample. This phenomenon was investigated for some years with the “model ion” chloride. A high number of samples (ca. 210) were analysed over three years with different analytical methods, and by alteration of the sample containers the discrete physical influence of the wall effect of the sample vessel could be worked out definitely. No significant differences occur with the mean value of the year but the single values have high differences in the positive or negative direction. Assuming a similar behaviour of other water constituents when preserved by freezing the analytical values had to be looked at very critically.
Effects of the Herbicide Metazachlor on Phytoplankton and Periphyton Communities in Outdoor Mesocosms
Authors: Noack Udo , Geffke Thomas , Balasubramanian Ramani , Papenbrock Jutta , Braune Mike , Scheerbaum Dirk
Published: March 2004

The effects of the chloroacetanilide herbicide metazachlor have been investigated in outdoor artificial mesocosms. Decreasing phytoplankton densities were caused by the application, however, the communities recovered after 30 to 35 days. Periphyton growth was found to be affected not only by the herbicide application but by the presence of species with different ability to grow on artificial substrates. Zooplankton diversity was small due to low density of ingestible algae species. Oxygen saturation was found to be correlated with the dosage levels of the herbicide in the second half of the study.
A Perspective of One‐Pot Pyrrole–Aldehyde Condensations as Versatile Self‐Assembly Processes
Authors: Ghosh Abhik
Published: March 2004

Regarded as the classic one‐pot synthetic route to symmetrical porphyrins for well over half a century, pyrrole–aldehyde cyclocondensations have yielded a cornucopia of nonporphyrin macrocycles, such as N‐confused porphyrins, corroles, sapphyrins, and expanded porphyrins, and have thus emerged as versatile self‐assembly processes. A highlight in this field is the remarkably general one‐pot corrole synthesis. The manifold of intermediates generated in the anaerobic phase of a Lindsey‐type synthesis have been viewed as a dynamic covalent self‐assembly system. This raises the possibility that the addition of a suitable host may alter the equilibrium concentrations of these intermediates by molecular recognition and related phenomena and thus determine the major product formed after oxidative quenching.
8‐Oxabicyclo[3.2.1]oct‐6‐en‐3‐ones: Application to the Asymmetric Synthesis of Polyoxygenated Building Blocks
Authors: Hartung Ingo V. , Hoffmann H. Martin R.
Published: March 2004

The development and design of reliable and efficient methods for the construction of chiral building blocks are crucial in modern natural product synthesis. 8‐Oxabicyclo[3.2.1]oct‐6‐en‐3‐ones are readily accessible scaffolds with defined stereochemical features which have been exploited for non‐aldol approaches to the preparation of chiral building blocks. Strategies for their enantioselective synthesis, including asymmetric cycloaddition methods, desymmetrization protocols, and “racemic switch operations”, are presented and evaluated.
Exploring the utility of functional analysis methodology to assess and treat problematic verbal behavior in persons with acquired brain injury
Authors: Dixon Mark R. , Guercio John , Falcomata Terry , Horner Molly J. , Root Shannon , Newell Catherine , Zlomke Kimberly
Published: March 2004

Functional analyses were conducted on four adults with acquired brain injuries who regularly displayed instances of inappropriate verbal behavior including depressive, aggressive, suicidal, profane, and sexually inappropriate utterances. After the functional analysis yielded a maintaining variable for each participant, a function‐based intervention consisting of differential reinforcement of alternative verbal behavior was implemented. Results of the behavioral interventions show that instances of vocal behavior can be assessed and subsequently treated using the functional analysis methodology often reserved for nonverbal forms of behavior. The utility of functional analysis for assessing complex human behavior is discussed. Copyright © 2004 John Wiley & Sons, Ltd.
Genuine Heteroleptic Complexes of Early Rare‐Earth Metals: Synthesis, X‐ray Structure, and Their Use for Stereospecific Isoprene Polymerization Catalysis
Authors: Bonnet Fanny , Visseaux Marc , Barbier‐Baudry Denise , Vigier Estelle , Kubicki Marek M.
Published: March 2004

Genuine heteroleptic neodymium and samarium complexes of formula [Cp*′Ln{(p‐tol)NN}(BH4)] (Cp*′ = C5Me4(nPr), (p‐tol)NN = (p‐tol)NC(Me)CHC(Me)N(p‐tol), Ln = Sm: 1 a, Ln = Nd: 1 b) have been synthesized for the first time. These unprecedented homologues of early lanthanocenes are prepared by a metathetic reaction between their monocyclopentadienylbisborohydrido precursors with the corresponding potassium diketiminate. Both complexes were obtained in good yields and were characterized by 1H NMR spectroscopy and elemental analysis. Complex 1 a has an non‐solvated dimeric structure, as indicated by its crystallographic data. The chloroneodymium analogue [Cp*′Nd{(p‐tol)NN}(Cl)] (2 b) was only obtained as a part of a mixture. Analysis of crystals of 2 b by X‐ray diffraction revealed a molecular structure very similar to that of 1 a. Preliminary isoprene polymerization experiments were carried out with 1 b in the presence of an alkylmagnesium coactivator. The resulting bimetallic Nd/Mg system behaves as an efficient and highly stereospecific catalyst with the synthesis of trans‐1,4‐polyisoprene with more than 98 % regularity. The control of the polymer structure is related to the steric hindrance around the lanthanide atom.
Molecular Logic Gates Based on Pentacyanoferrate Complexes: From Simple Gates to Three‐Dimensional Logic Systems
Authors: Szaciłowski Konrad
Published: March 2004

The article presents new aspects of reactivity of two pentacyanoferrates: [Fe(CN)5NO]2− and [Fe(CN)5N(O)SR]3−. The dependence of thermodynamic functions on cations was found for the reaction between nitroprusside and thiolate. The thermodynamic data are interpreted in terms of ion pairing and changes in the solvation shell of the cations. It was found that the reaction enthalpies and entropies depend strongly on the cation radius. The reaction volume in turn is strongly affected by the structure and properties of the hydration shell. Careful data analysis allowed the contribution of partial cation dehydration to the total reaction volume to be determined. The experimental results were also interpreted in terms of chemical logic gates. Complex logic systems were built from a number of cells containing a switching compound arranged in different geometric patterns. Increasing the dimensionality of these arrangements leads to really complex logic systems containing up to 20 AND and OR logic gates. The system is capable of processing up to 16 bits of input data.
Chiral Nonracemic Late‐Transition‐Metal Organometallics with a Metal‐Bonded Stereogenic Carbon Atom: Development of New Tools for Asymmetric Organic Synthesis
Authors: Malinakova Helena C.
Published: March 2004

Transition‐metal‐catalyzed cross‐coupling reactions and the Heck reaction have evolved into powerful tools for the construction of carbon–carbon bonds. In most cases, the reactive organometallic intermediates feature a carbon–transition‐metal σ bond between a sp2‐hybridized carbon atom and the transition metal (Csp2TM). New, and potentially more powerful approach to transition‐metal‐catalyzed asymmetric organic synthesis would arise if catalytic chiral nonracemic organometallic intermediates with a stereogenic sp3‐hybridized carbon atoms directly bonded to the transition metal (C*sp3TM bond) could be formed from racemic or achiral organic substrates, and subsequently participate in the formation of a new carbon–carbon bond (C*sp3–C) with retention of the stereochemical information. To date, only a few catalytic processes that are based on this concept, have been developed. In this account, both “classical” and recent studies on preparation and reactivity of stable chiral nonracemic organometallics with a metal‐bonded stereogenic carbon, which provide the foundation for the future design of new synthetic transformations exploiting the outlined concept, are discussed, along with examples of relevant catalytic processes.
Chemical Routes for Production of Transition‐Metal Phosphides on the Nanoscale: Implications for Advanced Magnetic and Catalytic Materials
Authors: Brock Stephanie L. , Perera Susanthri C. , Stamm Kimber L.
Published: March 2004

Nanoparticulate transition‐metal phosphides remain an unexplored, though emerging area of interest on the materials landscape, due principally to their promising magnetic and catalytic properties. This review describes synthetic strategies for the formation of both supported and unsupported transition‐metal phosphide nanoparticles, provides a summary of their relevant magnetic and catalytic properties, and indicates new directions for exploration.