bluuebunny/crossref_metadata_2025 huggingface dataset:
Breaking the Non‐Responsiveness of C57BL/6 Mice to the Malarial Antigen EB200 – The Role of Carrier and Adjuvant Molecules
Authors: Rahman Q. K. , Berzins K. , López M. C. , Fernández C.
Published: September 2003

Poor immunogenicity and major histocompatibility complex (MHC) restriction of immune responses to certain recombinant proteins or synthetic peptides impose problems in developing effective vaccines. EB200 is one of the vaccine candidate antigens from Plasmodium falciparum, which induces MHC‐restricted immune responses in mice of different haplotypes. A way of overcoming this problem is to conjugate the antigen to an immunogenic protein carrier and to use optimal adjuvant substances. We have investigated the carrier effect of glutathione‐S‐transferase (GST) in CBA and C57BL/6 mice which are high and low responder to EB200, respectively. Our results reveal that the MHC restriction in C57BL/6 mice was broken by the use of GST as a carrier. Studies on the B‐cell repertoires in both strains of mice immunized with GST‐EB200 by preparing hybridoma cell lines indicate that the B‐cell repertoires were similar in both CBA and C57BL/6 mice. However, the antibody affinity and the magnitude of the response were still lower in the low‐responder C57BL/6 mice compared with that in CBA even when cholera toxin (CT) was used as adjuvant. To improve the response, the efficacy of various adjuvant substances like alum and Hsp 70 from Trypanosoma cruzi and the combination of various adjuvants was analysed. CT and Hsp 70 together act synergistically and markedly improve the immunogenicity of EB200 by increasing antibody affinity and the magnitude of the responses in C57BL/6 mice, which may be explained by the complementary effect of adjuvants. These results are of importance in the design of efficient vaccines.
Immunobiological Effects of Glucosamine In Vitro
Authors: Forchhammer L. , Thorn M. , Met O. , Gad M. , Weidner M. S. , Claesson M. H.
Published: September 2003

Glucosamine (GlcN) and N‐acetyl‐d‐glucosamine (GlcNAc) were assayed in vitro for their effects on proliferation, cytotoxicity and cytokine secretion in primary and secondary mixed lymphocyte cultures (MLCs). In addition, we studied the effect of GlcN and GlcNAc on the proliferation of purified CD4+ T cells exposed to immobilized anti‐CD3 antibody. The present data show that GlcN, but not GlcNAc, inhibits CD4+ T‐cell proliferation, the generation of alloreactive cytotoxic T lymphocytes (CTLs) and the secretion of interferon‐γ (IFN‐γ) and interleukin‐5 (IL‐5) in primary MLC. In secondary T helper‐2 (Th2)‐polarized MLC, GlcN, but not GlcNAc, inhibits IL‐4 and IL‐5 secretion, whereas no effect was found on IFN‐γ secretion in Th1‐polarized MLC. Dendritic cells treated with GlcN showed a 75–80% decreased capacity for antigen cross‐presentation and allostimulation. In cellular bioassays, GlcN was shown to inhibit the stimulatory activity of IL‐4 and IL‐2, as well as the cytotoxic activity of tumour necrosis factor‐α (TNF‐α). In conclusion, GlcN suppresses unprimed T‐cell responses by interfering with antigen‐presenting cell functions and by a direct inhibitory effect on T‐cell proliferation. In addition, GlcN inhibits the secretion of cytokines in antigen‐stimulated unprimed T cells and primed Th2‐polarized cells.
Enhanced Adhesion to Laminin by Apoptotic Eosinophils
Authors: Seton K. , Håkansson L. , Venge P.
Published: September 2003

Apoptotic cells are regarded as inert bodies that turn off intracellular processes and functional capabilities. The objective was to study adhesion by eosinophils in relation to the apoptotic process. Eosinophils were cultured for up to 72 h. The living cells were separated from the apoptotic cells, and their adhesion to transfected cell lines expressing vascular cell adhesion molecule‐1 (VCAM‐1), intercellular adhesion molecule‐1 (ICAM‐1), E‐selectin and laminin was measured. To relate the functional studies with cell structure, the surface receptor expression of β1‐ and β2‐integrins was investigated by flow cytometry. Apoptotic eosinophils evidenced an increased expression of the α‐chain of the laminin receptor and CD49f and an increased ability to adhere to a laminin‐coated surface. Adhesion to the endothelial cell adhesion receptors E‐selectin, VCAM‐1 and ICAM‐1 was absent in apoptotic eosinophils and was paralleled by a low expression of CD11b, CD29, CD49d and CD66b. The specifically increased adhesion to laminin and expression of the laminin receptor α‐chain is a unique feature of apoptotic eosinophils. When an eosinophil goes into apoptosis, it still possesses the ability to interact with its environment. Our results point to new ideas as to how the apoptotic eosinophil behaves in apoptosis.
Mycobacterium tuberculosis Virulence Correlates with Mitochondrial Cytochrome c Release in Infected Macrophages
Authors: Abarca‐Rojano E. , Rosas‐Medina P. , Zamudio‐Cortéz P. , Mondragón‐Flores R. , Sánchez‐García F. J.
Published: September 2003

Mitochondria are at the centre of molecular events involved in energy production, cell survival and apoptosis. Mitochondrial membrane potential (Δψm) is maintained by cellular catabolic reactions and the electron transport chain of which cytochrome c is a constituent, whereas the proton leak pathway, ATP synthesis and turnover consume it. Mitochondrial alterations such as a drop in Δψm, swelling and cytochrome c release have been observed in apoptosis. However, there is a paucity of information concerning mitochondrial function in the course of intracellular infections, a process that must certainly induce stress on the host cell. This work analyses the effect that two strains of mycobacteria of opposing virulence have on the mitochondria of murine macrophages in the early stages of infection. It was found that infection of J774 cells with both Mycobacterium tuberculosis H37Ra and M. tuberculosis H37Rv readily induced changes in Δψm as well as in mitochondrial morphology at the ultrastructural level. In addition, an increase in cytosolic ATP was found at 24 h post infection with both strains of M. tuberculosis. Interestingly, only M. tuberculosis H37Rv was able to induce cytochrome c release from mitochondria to the cytosol, thus suggesting the occurrence in M. tuberculosis H37Rv of a specific factor(s) capable of regulating cytochrome c translocation. The precise role of cytochrome c release in the context of a mycobacterial infection remains to be elucidated.
Optimization of Functional Efficacy of Phosphorothioate‐Modified Oligonucleotides in a Human CD8+ T‐Cell Ex Vivo Expansion Model
Authors: Al‐Shanti N. A. , Steward C. G. , Garland R. J.
Published: September 2003

Antisense oligodeoxyribonucleotides (ODNs) can specifically inhibit gene expression, but their application to fresh human CD8+ T cells is limited by poor spontaneous uptake (<2%). We have examined and optimized the uptake of phosphorothioate‐modified oligodeoxyribonucleotides (PS‐ODNs) into these cells in an ex vivo expansion model. Optimal antisense treatments were found to be, for fresh CD8+ T cells, 1 µm PS‐ODNs complexed with lipofectin (LF), which resulted in 35% uptake and 10 µm PS‐ODNs in the absence of LF, for cultured cells, which resulted in 95% uptake. The delivered antisenses were functional, as determined by the inhibition of protein expression. In this respect, partially phosphorothioate‐modified ODNs (PS‐ODNs‐P) were twice as effective as completely modified (PS‐ODNs‐C), and the antisense specific for the cap site showed the highest protein suppression of those tested (68%). Uptake mechanisms were also investigated. To our knowledge, this is the first optimization of the delivery of antisense oligonucleotides into human CD8+ T cells. This protocol could be used to study the function of a particular gene in cytotoxic T lymphocytes and also by those looking for a method to deliver short interfering RNA into cell lines to specifically suppress a gene of interest.
Delta‐F508 cystic fibrosis mutation is not linked to intussusception: Implications for rotavirus vaccine
Authors: Barnes G , Srivastava A , Carlin J , Francis I
Published: September 2003

Objective: To determine whether the cystic fibrosis (CF) delta‐F508 gene mutation predisposes to intussusception, and so selects infants who should not receive rotavirus vaccine.

Methods:  Stored neonatal screening blood spots, retrieved from 81 infants with intussusception and from 79 controls, were tested for the presence of the CF delta‐F508 gene mutation.

Results:  Prevalence of the mutation was similar in blood specimens from intussusception patients and from controls.

Conclusion: Testing for the CF delta‐F508 mutation at birth is unlikely to identify infants predisposed to intussusception, and therefore is not relevant to rotavirus vaccine programs.
Respiratory health in Aboriginal and Torres Strait Islander children in the Australian Capital Territory
Authors: Glasgow NJ , Goodchild EA , Yates R , Ponsonby A‐L
Published: September 2003

Objectives:  To measure the prevalence of respiratory symptoms and atopic disease in Aboriginal and Torres Strait Islander (indigenous) and non‐indigenous children in the Australian Capital Territory (ACT).

Methods:  A two‐stage questionnaire survey of children in the ACT with stage two completed for children identified by parents as having respiratory symptoms or asthma in the first stage cross‐sectional survey. Participants in the study were: (i) all new entrant primary schoolchildren aged 4−6 years in 1999, 2000 and 2001, 217 being indigenous children and 10 604 being non‐indigenous children (80% of eligible); and (ii) Year 1−6 primary schoolchildren in 2000, with 216 being indigenous children and 14 202 being non‐indigenous children (52% of eligible). Respiratory symptoms (including recent wheeze and parent‐reported asthma) and other factors were measured by parental questionnaire.

Results:  Indigenous kindergarten children had more recent wheeze (21%, odds ratio (OR) 1.4 95% confidence interval (CI) 1.0−2.0)) and parent‐reported asthma (24%, OR 1.8 95% CI 1.3−2.5) than non‐indigenous children (both 15%). However, indigenous children had less eczema (25%, OR 0.7 95% CI 0.5−0.9) and hayfever (14%, OR 0.7 95% CI 0.5−1.0) than non‐indigenous children (32% and 19%, respectively). Among children with respiratory symptoms, the symptom severity did not differ between groups, but indigenous children were exposed to more environmental tobacco smoke (ETS) (63%, OR 3.5 95% CI 2.1−5.9) than non‐indigenous children (32%).

Conclusions:  Indigenous children in the ACT have more respiratory morbidity but less of the atopic diseases of hayfever and eczema than non‐indigenous children. Whether the respiratory morbidity represents ‘asthma’ or results from increased ETS exposure is unclear and needs to be further explored.
Vitamin D status of chronically ill or disabled children in Victoria
Authors: Greenway A , Zacharin M
Published: September 2003

Objective:  To establish the percentage prevalence of hypovitaminosis D in chronically ill or disabled children in Melbourne, Australia.

Methodology:  A group of inpatients at the Royal Children's Hospital, Melbourne, Victoria, as identified by the primary unit, were sampled to measure serum vitamin D and parameters of bone turnover. A second group of disabled children (outpatients) were also measured to establish vitamin D status.

Results:  Of the total population, 54.9% were found to have low serum 25 hydroxy (25OH) vitamin D levels. Of the inpatient group, 25.4% were vitamin D deficient (<30 nmol/L), and 27.1% were vitamin D insufficient (30−50 nmol/L). The mean 25OH vitamin D was 52.1 nmol/L. Of the outpatient group, 15.4% were vitamin D deficient, whilst 42.3% were found to be insufficient. The mean vitamin D level was 41.2 nmol/L. No difference attributable to intellectual versus physical disability was found. Anticonvulsant use and ambulatory status was not predictive of vitamin D status in the children examined. Of the total population, 0.05% were found to have secondary hyperparathyroidism. The mean 25OH vitamin D level of this subgroup was 30.6 nmol/L. Dark skin tone was found to be significantly associated with hypovitaminosis D (P = 0.001), where all five children with dark skin tone were found to have serum 25OH vitamin D levels <50 nmol/L. Of the seven disabled children (outpatients) found to be iron deficient, four had coexistent hypovitaminosis D.

Conclusion:  The percentage prevalence of hypovitaminosis D is high in both chronically ill, and physically/intellectually disabled children in Melbourne, Australia. Increased vigilance and recognition of this deficiency state is needed as an important health prevention strategy.
Infestation by cabbage aphid (Brevicoryne brassicae) on oilseed rape (Brassica napus) causes a long lasting induction of the myrosinase system
Authors: Pontoppidan Bo , Hopkins Richard , Rask Lars , Meijer Johan
Published: September 2003

Cabbage aphid, Brevicoryne brassicae (L.) (Hemiptera: Aphididae), is specialised on cruciferous plants and constitutes a world‐wide problem with a substantial negative impact on agriculture and horticulture. The myrosinase‐glucosinolate system present in crucifers is believed to serve as an important barrier to general herbivores, whereas specialist insects rely on this system for host recognition. Two proteins with unknown function, myrosinase binding protein (MBP) and myrosinase associated protein (MyAP), are also present in such plants and bind to specific myrosinases. In order to study regulation and overall effects on the myrosinase system, one leaf of oilseed rape (Brassica napus L.) (Brassicaceae) plants at the two‐leaf stage was exposed to cabbage aphids for 1 h. After removal of the insects, infested and non‐infested leaves were analysed by Northern blot analysis for the presence of MBP, MyAP, and myrosinase transcripts at different time points up to 48 h. MBP transcript levels continued to rise during the whole experiment, and were seven‐ to eight‐fold higher compared with control plants 48 h after removal of the aphids. At 24 h the MyAP transcripts reached maximal levels and were four‐fold higher than the control levels. Myrosinase transcripts were down regulated by aphid infestation and the level was less than half that of the control plants at 48 h. Apparently cabbage aphid infestation causes both transient and more long lasting (up to 48 h) effects on the myrosinase system of the host.
Characteristics associated with Woolly Apple Aphid Eriosoma lanigerum, resistance of three apple rootstocks
Authors: Sandanayaka W.R.M. , Bus V.G.M. , Connolly P. , Newcomb R.
Published: September 2003

The resistance characteristics of the apple resistance genes (Er1, Er2, and Er3) to the woolly apple aphid, Eriosoma lanigerum (Hausmann) (Homoptera: Aphididae) were studied according to the performance measured on apple cultivars containing these resistance genes. The resistance characteristics of Northern Spy (Er1), Robusta 5 (Er2), and Aotea (Er3) were compared to the susceptible cultivar Royal Gala, by measuring the aphid settlement, development, and survival rates correlated with electronically monitored probing behaviour. Er1 and Er2 had a higher level of resistance with a significantly shorter period of phloem feeding, suggesting that the resistance factors were present in the phloem tissue. Phenological measurements indicated that the aphids showed poor settlement, development, and survival on Er2. Er1 also showed low settlement and survival, although not as low as Er2. Aphid performance and feeding on Aotea (Er3) were similar to Royal Gala, suggesting that some woolly apple aphids in New Zealand may have recently overcome Er3 resistance. The differences in resistance mechanisms of Er1, Er2, and Er3 are discussed in relation to the strategy of pyramiding these genes to give a durable resistance to woolly apple aphid.
Resistance of virus to extinction on bottleneck passages: Study of a decaying and fluctuating pattern of fitness loss
Authors: Lázaro Ester , Escarmís Cristina , Pérez-Mercader Juan , Manrubia Susanna C. , Domingo Esteban
Published: September 2003

RNA viruses display high mutation rates and their populations replicate as dynamic and complex mutant distributions, termed viral quasispecies. Repeated genetic bottlenecks, which experimentally are carried out through serial plaque-to-plaque transfers of the virus, lead to fitness decrease (measured here as diminished capacity to produce infectious progeny). Here we report an analysis of fitness evolution of several low fitness foot-and-mouth disease virus clones subjected to 50 plaque-to-plaque transfers. Unexpectedly, fitness decrease, rather than being continuous and monotonic, displayed a fluctuating pattern, which was influenced by both the virus and the state of the host cell as shown by effects of recent cell passage history. The amplitude of the fluctuations increased as fitness decreased, resulting in a remarkable resistance of virus to extinction. Whereas the frequency distribution of fitness in control (independent) experiments follows a log-normal distribution, the probability of fitness values in the evolving bottlenecked populations fitted a Weibull distribution. We suggest that multiple functions of viral genomic RNA and its encoded proteins, subjected to high mutational pressure, interact with cellular components to produce this nontrivial, fluctuating pattern.
Affective style andin vivoimmune response: Neurobehavioral mechanisms
Authors: Rosenkranz Melissa A. , Jackson Daren C. , Dalton Kim M. , Dolski Isa , Ryff Carol D. , Singer Burt H. , Muller Daniel , Kalin Ned H. , Davidson Richard J.
Published: September 2003

Considerable evidence exists to support an association between psychological states and immune function. However, the mechanisms by which such states are instantiated in the brain and influence the immune system are poorly understood. The present study investigated relations among physiological measures of affective style, psychological well being, and immune function. Negative and positive affect were elicited by using an autobiographical writing task. Electroencephalography and affect-modulated eye-blink startle were used to measure trait and state negative affect. Participants were vaccinated for influenza, and antibody titers after the vaccine were assayed to provide anin vivomeasure of immune function. Higher levels of right-prefrontal electroencephalographic activation and greater magnitude of the startle reflex reliably predicted poorer immune response. These data support the hypothesis that individuals characterized by a more negative affective style mount a weaker immune response and therefore may be at greater risk for illness than those with a more positive affective style.
Specificity in the activation and control of transcription factor E2F-dependent apoptosis
Authors: Hallstrom Timothy C. , Nevins Joseph R.
Published: September 2003

Previous work has demonstrated a role for the E2F1 gene product in signaling apoptosis, both as a result of the deregulation of the Rb/E2F pathway as well as in response to DNA damage. We now show that the ability of cells to suppress the apoptotic potential of E2F1, as might occur during the course of normal cellular proliferation, requires the action of the Ras–phosphoinositide 3-kinase–Akt signaling pathway. In addition, we also identify a domain within the E2F1 protein, previously termed the marked-box domain, that is essential for the apoptotic activity of E2F1 and that distinguishes the E2F1 protein from E2F3. We also show that the E2F1-marked-box domain is essential for the induction of both p53 and p73 accumulation. Importantly, a role for the marked-box domain in the specificity of E2F1-mediated apoptosis coincides with recent work demonstrating a role for this domain in achieving specificity in the activation of transcription. We conclude that the unique capacity of E2F1 to trigger apoptosis reflects a specificity of transcriptional activation potential, and that this role for E2F1 is regulated through the action of the Akt protein kinase.
Ionizing radiation induces heritable disruption of epithelial cell interactions
Authors: Park Catherine C. , Henshall-Powell Rhonda L. , Erickson Anna C. , Talhouk Rabih , Parvin Bahram , Bissell Mina J. , Barcellos-Hoff Mary Helen
Published: September 2003

Ionizing radiation (IR) is a known human breast carcinogen. Although the mutagenic capacity of IR is widely acknowledged as the basis for its action as a carcinogen, we and others have shown that IR can also induce growth factors and extracellular matrix remodeling. As a consequence, we have proposed that an additional factor contributing to IR carcinogenesis is the potential disruption of critical constraints that are imposed by normal cell interactions. To test this hypothesis, we asked whether IR affected the ability of nonmalignant human mammary epithelial cells (HMEC) to undergo tissue-specific morphogenesis in culture by using confocal microscopy and imaging bioinformatics. We found that irradiated single HMEC gave rise to colonies exhibiting decreased localization of E-cadherin, β-catenin, and connexin-43, proteins necessary for the establishment of polarity and communication. Severely compromised acinar organization was manifested by the majority of irradiated HMEC progeny as quantified by image analysis. Disrupted cell–cell communication, aberrant cell–extracellular matrix interactions, and loss of tissue-specific architecture observed in the daughters of irradiated HMEC are characteristic of neoplastic progression. These data point to a heritable, nonmutational mechanism whereby IR compromises cell polarity and multicellular organization.
A tale of two TUTases
Authors: Aphasizhev Ruslan , Aphasizheva Inna , Simpson Larry
Published: September 2003

The insertion and deletion of U residues at specific sites in mRNAs in trypanosome mitochondria is thought to involve 3′ terminal uridylyl transferase (TUTase) activity. TUTase activity is also required to create the nonencoded 3′ oligo[U] tails of the transacting guide RNAs (gRNAs). We have described two TUTases, RET1 (RNA editing TUTase 1) and RET2 (RNA editing TUTase 2) as components of different editing complexes. Tandem affinity purification-tagged
Trypanosoma brucei
RET2 (TbRET2) was expressed and localized to the cytosol in
Leishmania tarentolae
cells by removing the mitochondrial signal sequence. Double-affinity isolation yielded tagged TbRET2, together with a few additional proteins. This material exhibits a U-specific transferase activity in which a single U is added to the 3′ end of a single-stranded RNA, thereby confirming that RET2 is a 3′ TUTase. We also found that RNA interference of RET2 expression in
T. brucei
inhibits
in vitro
U-insertion editing and has no effect on the length of the 3′ oligo[U] tails of the gRNAs, whereas down-regulation of RET1 has a minor effect on
in vitro
U-insertion editing, but produces a decrease in the average length of the oligo[U] tails. This finding suggests that RET2 is responsible for U-insertions at editing sites and RET1 is involved in gRNA 3′ end maturation, which is essential for creating functional gRNAs. From these results we have functionally relabeled the previously described TUT-II complex containing RET1 as the guide RNA processing complex.
Correction of proximal tubule phosphate transport defect inHypmicein vivoandin vitrowith indomethacin
Authors: Baum Michel , Loleh Samer , Saini Neel , Seikaly Mouin , Dwarakanath Vangipuram , Quigley Raymond
Published: September 2003

X-linked hypophosphatemia is the most prevalent inherited form of rickets. In this disorder, rickets results from hyperphosphaturia and inappropriately normal levels of 1,25(OH)2-vitamin D. Current therapy with oral phosphate and vitamin D improves the rickets, but has significant morbidity and does not significantly affect the short stature and hypophosphatemia. In the present study, we demonstrate thatHypmice, which have a mutation homologous to that in patients with X-linked hypophosphatemia, have a 2-fold greater urinary prostaglandin E2(PGE2) excretion than C57/B6 mice. To determine whether PGs were involved in the pathogenesis of this disorder,Hypand C57/B6 mice received i.p. injections with vehicle or indomethacin (1 mg/kg of body weight twice daily for 4 days) and were studied ≈12 h after the last dose of indomethacin. In theHypmice, indomethacin treatment decreased the fractional excretion of phosphate from 13.0 ± 3.2% to 2.2 ± 1.1% (P< 0.05), and increased serum phosphate from 2.9 ± 0.2 mg/dl to 4.1 ± 0.2 mg/dl (P< 0.05). There was no effect of indomethacin in C57/B6 mice. Indomethacin did not affect serum creatinine or inulin clearance, demonstrating that the normalization of urinary phosphate excretion was not caused by changes in glomerular filtration rate. Indomethacin treatment increased renal brush border membrane vesicle NaPi-2 protein abundance inHypmice to levels comparable to that of C57/B6 mice, but had no effect in C57/B6 mice.In vitroisolated perfused proximal tubule studies demonstrate directly that 10-6M bath indomethacin normalized the phosphate transport defect inHypmice but had no effect on C57/B6 mice. In conclusion, there is dysregulation of renal PG metabolism inHypmice, and indomethacin treatment normalizes the urinary excretion of phosphate by a direct tubular effect.
The conformation of neurotensin bound to its G protein-coupled receptor
Authors: Luca Sorin , White Jim F. , Sohal Awinder K. , Filippov Dmitri V. , van Boom Jacques H. , Grisshammer Reinhard , Baldus Marc
Published: September 2003

G protein-coupled receptors (GPCRs) mediate the perception of smell, light, taste, and pain. They are involved in signal recognition and cell communication and are some of the most important targets for drug development. Because currently no direct structural information on high-affinity ligands bound to GPCRs is available, rational drug design is limited to computational prediction combined with mutagenesis experiments. Here, we present the conformation of a high-affinity peptide agonist (neurotensin, NT) bound to its GPCR NTS-1, determined by direct structural methods. Functional receptors were expressed inEscherichia coli, purified in milligram amounts by using optimized procedures, and subsequently reconstituted into lipid vesicles. Solid-state NMR experiments were tailored to allow for the unequivocal detection of microgram quantities of13C,15N-labeled NT(8–13) in complex with functional NTS-1. The NMR data are consistent with a disordered state of the ligand in the absence of receptor. Upon receptor binding, the peptide undergoes a linear rearrangement, adopting a β-strand conformation. Our results provide a viable structural template for further pharmacological investigations.
Independent β-arrestin 2 and G protein-mediated pathways for angiotensin II activation of extracellular signal-regulated kinases 1 and 2
Authors: Wei Huijun , Ahn Seungkirl , Shenoy Sudha K. , Karnik Sadashiva S. , Hunyady László , Luttrell Louis M. , Lefkowitz Robert J.
Published: September 2003

Stimulation of a mutant angiotensin type 1A receptor (DRY/AAY) with angiotensin II (Ang II) or of a wild-type receptor with an Ang II analog ([sarcosine
1
,Ile
4
,Ile
8
]Ang II) fails to activate classical heterotrimeric G protein signaling but does lead to recruitment of β-arrestin 2-GFP and activation of extracellular signal-regulated kinases 1 and 2 (ERK1/2) (maximum stimulation ≈50% of wild type). This G protein-independent activation of mitogen-activated protein kinase is abolished by depletion of cellular β-arrestin 2 but is unaffected by the PKC inhibitor Ro-31-8425. In parallel, stimulation of the wild-type angiotensin type 1A receptor with Ang II robustly stimulates ERK1/2 activation with ≈60% of the response blocked by the PKC inhibitor (G protein dependent) and the rest of the response blocked by depletion of cellular β-arrestin 2 by small interfering RNA (β-arrestin dependent). These findings imply the existence of independent G protein- and β-arrestin 2-mediated pathways leading to ERK1/2 activation and the existence of distinct “active” conformations of a seven-membrane-spanning receptor coupled to each.
Polydispersity of a mammalian chaperone: Mass spectrometry reveals the population of oligomers in αB-crystallin
Authors: Aquilina J. Andrew , Benesch Justin L. P. , Bateman Orval A. , Slingsby Christine , Robinson Carol V.
Published: September 2003

The quaternary structure of the polydisperse mammalian chaperone αB-crystallin, a member of the small heat-shock protein family, has been investigated by using electrospray mass spectrometry. The intact assemblies give rise to mass spectra that are complicated by the overlapping of charge states from the different constituent oligomers. Therefore, to determine which oligomers are formed by this protein, tandem mass spectrometry experiments were performed. The spectra reveal a distribution, primarily of oligomers containing 24–33 subunits, the relative populations of which were quantified, to reveal a dominant species being composed of 28 subunits. Additionally, low levels of oligomers as small as 10-mers and as large as 40-mers were observed. Interpretation of the tandem mass spectral data was confirmed by simulating and summing spectra arising from the major individual oligomers. The ability of mass spectrometry to quantify the relative populations of particular oligomeric states also revealed that, contrary to the dimeric associations observed in other small heat-shock proteins, there is no evidence for any stable substructures of bovine αB-crystallin isolated from the lens.
Interaction of a selective cyclooxygenase-2 inhibitor with aspirin and NO-releasing aspirin in the human gastric mucosa
Authors: Fiorucci Stefano , Santucci Luca , Wallace John L. , Sardina Marco , Romano Mario , del Soldato Piero , Morelli Antonio
Published: September 2003

In addition to inhibiting cyclooxygenase (COX)-1-derived prostanoid biosynthesis, aspirin acetylates COX-2, enabling the conversion of arachidonic acid to 15(
R
)-epi lipoxin A
4
, or aspirin-triggered lipoxin (ATL). Selective COX-2 inhibitors block ATL formation and exacerbate mucosal injury in rats treated with aspirin. In the present study, we have examined whether inhibition of COX-2 activity in healthy volunteers taking aspirin exacerbates gastric mucosal injury and if such an effect would be prevented by NCX-4016, a NO-releasing derivative of aspirin. Thirty-two volunteers were randomized to receive 2 wk of treatment with NCX-4016 (800 mg twice a day) or aspirin (100 mg once a day) alone or in combination with 200 mg of celecoxib twice a day. Mucosal damage was assessed by endoscopy. The mean mucosal injury score was 5.8 ± 1.8 in subjects treated with aspirin and 2.4 ± 0.7 (
P
< 0.01 vs. aspirin) in subjects treated with NCX-4016. Administration of celecoxib increased the injury score in volunteers treated with aspirin (9.9 ± 1.9) but not in subjects taking NCX-4016 (1.5 ± 0.8). Aspirin and NCX-4016 caused a comparable suppression of serum thromboxane B
2
levels and increased urinary excretion of ATL. Celecoxib inhibited endotoxin-induced prostaglandin E
2
generation in whole blood by ≈80% and abolished ATL formation. These findings suggests that (
i
) aspirin and NCX-4016 trigger ATL formation in humans, (
ii
) celecoxib inhibits ATL formation and exacerbates the mucosal injury caused by low doses of aspirin, and (
iii
) the NO-donating moiety of NCX-4016 protects the gastric mucosa even in the presence of suppression of COX-1 and COX-2.
Nitric oxide inhibits H
2
O
2
-induced transferrin receptor-dependent apoptosis in endothelial cells: Role of ubiquitin-proteasome pathway
Authors: Kotamraju Srigiridhar , Tampo Yoshiko , Keszler Agnes , Chitambar Christopher R. , Joseph Joy , Haas Arthur L. , Kalyanaraman B.
Published: September 2003

We investigated here the mechanism of cytoprotection of nitric oxide (
•
NO) in bovine aortic endothelial cells treated with H
2
O
2
. NONOates were used as
•
NO donors that released
•
NO slowly at a well defined rate in the extracellular and intracellular milieus. H
2
O
2
-mediated intracellular dichlorofluorescein fluorescence and apoptosis were enhanced by the transferrin receptor (TfR)-mediated iron uptake.
•
NO inhibited the TfR-mediated iron uptake, dichlorofluorescein fluorescence, and apoptosis in H
2
O
2
-treated cells.
•
NO increased the proteasomal activity and degradation of nitrated TfR via ubiquitination.
N
ω
-nitro-
l
-arginine methyl ester, a nonspecific inhibitor of endogenous
•
NO biosynthesis, decreased the trypsin-like activity of 26S proteasome.
•
NO, by activating proteolysis, mitigates TfR-dependent iron uptake, dichlorodihydrofluorescein oxidation, and apoptosis in H
2
O
2
-treated bovine aortic endothelial cells. The relevance of biological nitration on redox signaling is discussed.
Culture and point of view
Authors: Nisbett Richard E. , Masuda Takahiko
Published: September 2003

East Asians and Westerners perceive the world and think about it in very different ways. Westerners are inclined to attend to some focal object, analyzing its attributes and categorizing it in an effort to find out what rules govern its behavior. Rules used include formal logic. Causal attributions tend to focus exclusively on the object and are therefore often mistaken. East Asians are more likely to attend to a broad perceptual and conceptual field, noticing relationships and changes and grouping objects based on family resemblance rather than category membership. Causal attributions emphasize the context. Social factors are likely to be important in directing attention. East Asians live in complex social networks with prescribed role relations. Attention to context is important to effective functioning. More independent Westerners live in less constraining social worlds and have the luxury of attending to the object and their goals with respect to it. The physical “affordances” of the environment may also influence perception. The built environments of the East are more complex and contain more objects than do those of the West. In addition, artistic products of the East emphasize the field and deemphasize individual objects, including people. Western art renders less of the field and emphasizes individual objects and people.
(+)-Larreatricin hydroxylase, an enantio-specific polyphenol oxidase from the creosote bush (
Larrea tridentata
)
Authors: Cho Man-Ho , Moinuddin Syed G. A. , Helms Gregory L. , Hishiyama Shojiro , Eichinger Dietmar , Davin Laurence B. , Lewis Norman G.
Published: September 2003

An enantio-specific polyphenol oxidase (PPO) was purified ≈1,700-fold to apparent homogeneity from the creosote bush (
Larrea tridentata
), and its encoding gene was cloned. The posttranslationally processed PPO (≈43 kDa) has a central role in the biosynthesis of the creosote bush 8–8′ linked lignans, whose representatives, such as nordihydroguaiaretic acid and its congeners, have potent antiviral, anticancer, and antioxidant properties. The PPO primarily engenders the enantio-specific conversion of (+)-larreatricin into (+)-3′-hydroxylarreatricin, with the regiochemistry of catalysis being unambiguously established by different NMR spectroscopic analyses; the corresponding (–)-enantiomer did not serve as a substrate. This enantio-specificity for a PPO, a representative of a widespread class of enzymes, provides additional insight into their actual physiological roles that hitherto have been difficult to determine.
Chronic, multisite, multielectrode recordings in macaque monkeys
Authors: Nicolelis Miguel A. L. , Dimitrov Dragan , Carmena Jose M. , Crist Roy , Lehew Gary , Kralik Jerald D. , Wise Steven P.
Published: September 2003

A paradigm is described for recording the activity of single cortical neurons from awake, behaving macaque monkeys. Its unique features include high-density microwire arrays and multichannel instrumentation. Three adult rhesus monkeys received microwire array implants, totaling 96–704 microwires per subject, in up to five cortical areas, sometimes bilaterally. Recordings 3–4 weeks after implantation yielded 421 single neurons with a mean peak-to-peak voltage of 115 ± 3 μV and a signal-to-noise ratio of better than 5:1. As many as 247 cortical neurons were recorded in one session, and at least 58 neurons were isolated from one subject 18 months after implantation. This method should benefit neurophysiological investigation of learning, perception, and sensorimotor integration in primates and the development of neuroprosthetic devices.
Nuclear actin and protein 4.1: Essential interactions during nuclear assembly
in vitro
Authors: Krauss Sharon Wald , Chen Cynthia , Penman Sheldon , Heald Rebecca
Published: September 2003

Structural protein 4.1, which has crucial interactions within the spectrin–actin lattice of the human red cell membrane skeleton, also is widely distributed at diverse intracellular sites in nucleated cells. We previously showed that 4.1 is essential for assembly of functional nuclei
in vitro
and that the capacity of 4.1 to bind actin is required. Here we report that 4.1 and actin colocalize in mammalian cell nuclei using fluorescence microscopy and, by higher-resolution detergent-extracted cell whole-mount electron microscopy, are associated on nuclear filaments. We also devised a cell-free assay using
Xenopus
egg extract containing fluorescent actin to follow actin during nuclear assembly. By directly imaging actin under nonperturbing conditions, the total nuclear actin population is retained and visualized
in situ
relative to intact chromatin. We detected actin initially when chromatin and nuclear pores began assembling. As nuclear lamina assembled, but preceding DNA synthesis, actin distributed in a reticulated pattern throughout the nucleus. Protein 4.1 epitopes also were detected when actin began to accumulate in nuclei, producing a diffuse coincident pattern. As nuclei matured, actin was detected both coincident with and also independent of 4.1 epitopes. To test whether acquisition of nuclear actin is required for nuclear assembly, the actin inhibitor latrunculin A was added to
Xenopus
egg extracts during nuclear assembly. Latrunculin A strongly perturbed nuclear assembly and produced distorted nuclear structures containing neither actin nor protein 4.1. Our results suggest that actin as well as 4.1 is necessary for nuclear assembly and that 4.1–actin interactions may be critical.
The Optimal Time to License a Biotech “Lemon”
Authors: Furtan W. H. , Gray R. S. , Holzman J. J.
Published: September 2003

Genetically modified (GM) wheat is an example of an irreversible technology that will cause environmental and market externalities. The optimal time to license this irreversible technology is examined using real options theory. Given the likely spread of the GM wheat genetics in the environment, the decision to license and adopt GM wheat will increase future herbicide costs for both adopters and nonadopters. Also, without the ability to segregate GM and non‐GM varieties, the market price of wheat is reduced for all producers. This creates a licensing dilemma due to the “lemon” characteristics of the new technology. (JEL Q18, D62)
Budget Deficits and Inflation: The Roles of Central Bank Independence and Financial Market Development
Authors: Neyapti Bilin
Published: September 2003

This article investigates the relationship between budget deficits and inflation with the view that the nature of this relationship depends on the characteristics of monetary and financial institutions. The main hypothesis is that budget deficits are especially inflationary when both the central bank is not independent and the financial market is not developed enough to contain inflationary expectations. The empirical analysis using a panel data that comprises 54 developed and less developed countries, with one to two decades of observations for each, supports this hypothesis. The findings are also robust to subsets of the sample. (JEL E58, H62)
The Political Economy of Growth in Latin America and East Asia: Some Empirical Evidence
Authors: Comeau Ludovic
Published: September 2003

This article examines the historical records of poor economic performance of Latin America compared to East Asia's relative success in the 1970s and 1980s. Although both regions adopted similar postwar protective inward‐oriented development strategies, their experiences and economic outcomes diverged significantly in subsequent years. Some have argued that East Asian countries outperformed Latin American ones because they implemented appropriate policies that were adaptive to changes in the global market scene. This study shows that the respective sociopolitical and institutional environment of the two regions was also an important factor contributing to their economic outcomes. A growth model augmented with policy‐driven and sociopolitical variables is developed. Using data for selected countries in both regions, the results confirm the hypothesis of a negative direct (efficiency) effect of sociopolitical instability on growth, with an additional indirect (accumulation) effect through investment, irrespective of a country's location. Policies adopted by governments, particularly to control inflation and foreign indebtedness and to enhance economic freedom and human capital accumulation, appear crucial for stability. Such policies influenced economic performance through both the direct and the indirect channels. (JEL B25, E13, F43, H19, O57)
Modeling the Legislator as an Agent for the Party: The Effects of Strict Party Discipline on Legislator Voting Behavior
Authors: Longley Neil
Published: September 2003

This article argues that in legislative systems where absolute party discipline is present, the only means by which a legislator can dissent from the party position is to abstain from voting. It is argued that abstentions are more likely to occur where the party‐imposed position causes conflict for the legislator—either because the party‐imposed position conflicts with the interests of the legislator's constituents or because it conflicts with the legislator's personal ideology. The hypothesis is empirically tested by examining voting in the Canadian House of Commons on the bill to implement the politically controversial Canada–U.S. Free Trade Agreement. The empirical results lend general support to the theoretical notions. (JEL D70, D72)
Identifying Efficient Crime‐Combating Policies by VAR Models: The Example of Switzerland
Authors: Funk Patricia , Kugler Peter
Published: September 2003

Current research suggests that the crime‐combating instrument sentence probability is more effective than sentence severity. However, the focus of the simultaneous (or very short‐run) impact of the law enforcement policy on crime impedes a comparison of these two instruments with respect to their long‐term effectiveness. With Swiss data, this article investigates the dynamic interrelationships between enforcement policy and crime and finds that overall, sentence severity is about the same effective as sentence probability. Furthermore, the authors show how the VAR‐modeling technique can be exploited to conveniently distinguish between deterrence and incapacitation effects. More concrete recommendations toward a cost‐effective crime‐reduction policy can be derived. (JEL C32, K42)
Mystery of Intron Gain
Authors: Fedorov Alexei , Roy Scott , Fedorova Larisa , Gilbert Walter
Published: September 2003

For nearly 15 years, it has been widely believed that many introns were recently acquired by the genes of multicellular organisms. However, the mechanism of acquisition has yet to be described for a single animal intron. Here, we report a large-scale computational analysis of the human, Drosophila melanogaster, Caenorhabditis elegans, and Arabidopsis thaliana genomes. We divided 147,796 human intron sequences into batches of similar lengths and aligned them with each other. Different types of homologies between introns were found, but none showed evidence of simple intron transposition. Also, 106,902 plant, 39,624 Drosophila, and 6021 C. elegans introns were examined. No single case of homologous introns in nonhomologous genes was detected. Thus, we found no example of transposition of introns in the last 50 million years in humans, in 3 million years in Drosophila and C. elegans, or in 5 million years in Arabidopsis. Either new introns do not arise via transposition of other introns or intron transposition must have occurred so early in evolution that all traces of homology have been lost.
The local food sector
Authors: Morris Carol , Buller Henry
Published: September 2003

“Local food” is attracting considerable policy and public interest, but evidence is lacking about the emerging contours of the local food sector. This paper offers a preliminary assessment of the local food sector in the county of Gloucestershire. Based on interviews with farmers and retailers, it investigates the scope of local food production in the county, assesses the nature of the local food chain and considers the potential of local food production and marketing for adding value for the various actors in the chain, from producer to retailer. Questions are raised in the conclusion about the coherence and sustainability of the local food sector in the county given the differences in the ways in which producers and retailers construct “local” and some unintended consequences of the efforts to promote local food.
The entrepreneurial summer school as a successful model for teaching enterprise
Authors: Collins Amanda , Robertson Martyn
Published: September 2003

What is the most effective approach to teaching enterprise? A residential week‐long event brought together students and tutors from a variety of backgrounds and with differing expertise. The result was a melting‐pot of ideas, some of which generated new businesses. This article critically examines the approach taken on the first of what have become an annual event and includes evaluation by the participants themselves. A literature review of teaching in enterprise is given as a back‐cloth to the format of the event itself. Qualitative reports from the participants show a significant degree of success, the main factors in which are highlighted and advanced by recommendations for taking students through to subsequent stages of start‐up.
Innovative organizational structures and performance
Authors: Ogbonna Emmanuel , Harris Lloyd C.
Published: September 2003

Although there has been substantial academic and practitioner interest into innovative structural arrangements, the study of structural transformation and the structural practices of small to medium‐sized organizations in traditional industries has been relatively ignored. This article presents empirical evidence of a company that changed its organizational structure from a traditional bureaucracy to a structure that was fundamentally different from those of other firms within its industry. The changed structure was characterized by many novel attributes such as devolved responsibility, empowerment, community orientation and a lack of hierarchy. Although there was some evidence to suggest that the structure had positive performance implications, the study also finds that the content, context and process of change were influenced by a dominant managing director such that the outcomes masked underlying political issues. The article concludes by discussing the theoretical and practical implications of the findings.