bluuebunny/crossref_metadata_2025 huggingface dataset:
Immunoglobulin uptake and processing by Schistosoma mansoni
Authors: THORS C. , JOKIRANTA T. S. , MERI T. , KAIREMO K. , MERI S. , LINDER E.
Published: August 2006

Intravascular Schistosoma mansoni worms seem to take up immunoglobulins from blood by surface Fc‐receptors, but the process whereby bound immunoglobulins are processed by the parasite is poorly understood. We here present morphological data suggesting that two distinct main processes are involved: Host immunoglobulins were seen at two distinct locations in the parasite: in the frontal part of the enteric tube, the oesophagus, and as a fine granular staining at the surface and in the subtegumental region. The latter staining pattern corresponds to host immunoglobulin localization in discrete organelle‐like aggregates tentatively identified as ‘discoid or elongate bodies’ at the ultrastructural level using immunogold staining. Immunoglobulin uptake by intravascular worms was also demonstrated in vivo after passive administration of 125I‐labelled rabbit and mouse immunoglobulins. Radiolabelled immunoglobulins were taken up by the worms and shown to localize as fine strands running perpendicular to the parasite surface. Our results suggest that intravascular schistosomes take up host immunoglobulins both as part of their enteric digestion and by a surface Fc‐receptor‐mediated mechanism, involving transport and processing within organelles, ‘elongate bodies’. Immunoglobulins taken up by intravascular schistosomes form a distinct organelle‐like granules, which seem to be processed within the excretory system of the parasite.
Anti‐ergotypic Immunoregulation
Authors: Quintana F. J. , Cohen I. R.
Published: August 2006

T‐cell vaccination (TCV) controls pathogenic autoimmune T‐cell responses via two different regulatory cell populations: anti‐idiotypic and anti‐ergotypic T cells. Anti‐idiotypic T cells recognize clone‐specific determinants, like the CDR3 region of the T‐cell receptor. Anti‐ergotypic T cells recognize antigenic determinants derived from activation markers, which are upregulated by activated T cells, like CD25. In this review, we analyse the different components of the anti‐ergotypic response: (1) the target T cells, which can be CD8+ or CD4+ T cells that express TCRαβ or TCRγδ; (2) the ergotope, which can be a T cell‐restricted ergotope not expressed by other cell types or a widely expressed, shared ergotope and (3) the anti‐ergotypic T cells, which are detectable in the naive immune system, but whose numbers can be expanded during the induction of an immune response against, or as a result of TCV or specific, anti‐ergotypic vaccination. Finally, we discuss possible interactions between anti‐ergotypic regulators and other regulatory T cells. We propose that the expression of major histocompatibility complex class II molecules by regulatory CD4+CD25+ T cells may make possible the cross‐regulation of anti‐ergotypic and CD4+CD25+ regulatory T cells, fine‐tuning immunoregulation in the mature immune system.
Regulatory T Cells and Systemic Lupus Erythematosus
Authors: Mudd P. A. , Teague B. N. , Farris A. D.
Published: August 2006

CD4+CD25+ regulatory T cells (Treg) constitute an important mechanism of peripheral immune tolerance. Organ‐specific autoimmune conditions, such as thyroiditis and insulin‐dependent diabetes mellitus have been attributed to a breakdown of this tolerance mechanism. However, this T‐cell subset has not been well studied in patients and mice with systemic lupus erythematosus (SLE; lupus). The information that has been gathered so far using new tools that discriminate Treg from activated T cells indicates that reduced numbers of Treg may exist in patients with lupus. In addition, potential defects in SLE Treg function have been documented in humans and mice. Our group has demonstrated equivalent proportions of thymic Treg in lupus prone and normal mice. We therefore propose that Treg function in SLE is the more important factor to address in future studies of murine lupus. Recent studies have shown that Toll‐like receptor (TLR) ligation can result in an abrogation of Treg‐mediated suppression; specifically ligation of TLR‐2, ‐4, ‐8 and ‐9. We address this new information about TLRs and Treg and propose a model for Treg tolerance breakdown to nucleic acid‐binding SLE autoantigens.
Phenotype of Genetically Regulated Thymic Involution in Young BXD RI Strains of Mice
Authors: Wang X. , Hsu H.‐C. , Wang Y. , Edwards C. K. , Yang P. , Wu Q. , Mountz J. D.
Published: August 2006

Age‐related thymic involution is a multifactorial process related to age‐related changes in intrathymic T‐cell development and cytokines. In contrast, early thymic involution, because of genetic differences that cause rapid or slow thymic involution at younger age, is less well characterized. Here, we analysed three representative rapid‐involuting strains of mice, BXD 8, 18 and 32, compared with three representative slow‐involuting strains, BXD 9, 19 and 29, all at 2 months of age. In rapid‐involuting strains compared with slow involution strains, thymocyte production, as indicated by CD4+ and CD8+ T‐cell receptor recombination excision circle (TREC), were decreased. Rapid‐involution strains of mice exhibited a developmental block at the DN1 to DN2 and CD4−CD8− (DN) to CD4+CD8+ (double positive, DP) transition stages. There was also increased susceptibility to H2O2‐induced apoptosis, decreased thymic expression of IL‐7, decreased expression of an IL‐7 downstream anti‐apoptosis gene, Bcl‐2, and increased expression of a pro‐apoptotic gene, Bad. In contrast, IL‐7R expression was higher on DN thymocytes of rapid‐involution strains. The increased expression of IL‐7R was associated with an increased thymocyte proliferation in response to anti‐CD3 + IL‐7 or anti‐CD3 + IL‐12 + IL‐7. These findings indicate that, even at young age, genetic differences of IL‐7/IL‐7R regulation pathway in BXD strains of mice can lead to characteristic phenotypic changes that have been previously associated with age‐related thymic involution.
Diversity of the Ig Repertoire is Maintained With Age In Spite of Reduced Germinal Centre Cells in Human Tonsil Lymphoid Tissue
Authors: Kolar G. R. , Mehta D. , Wilson P. C. , Capra J. D.
Published: August 2006

Humans and almost all species studied to date exhibit a decreased responsiveness to immunization and increased autoimmunity with age. While this has been observed clinically for decades, only recently has an understanding of the molecular basis for these changes begun to be appreciated. Studies of the B‐cell aspects of these changes in ageing mice and the very few reports in ageing humans have not been conclusive. Here we examine the nucleotide sequence of over 1250 VH transcripts from the tonsils of individuals of various ages for changes to the VH4 immunoglobulin repertoire. An exhaustive examination of VH, DH and JH gene segment utilization revealed a remarkable similarity of the repertoires. The extent of somatic hypermutation was fully maintained or even increased by some measures into the eighth decade of life. However, we found by middle age that the representation of naïve and germinal centre B‐cell subpopulations changed relative to total B lymphocytes in the tonsil. While the percentage of naïve and germinal centre B‐cell subpopulations changes during the second half of life, these findings suggest that even with advancing age, humans remain capable of generating an extremely diverse Ig repertoire while maintaining a similar spectrum of Ig rearrangements once the germinal centre reaction begins.
Autoantibody Determination in the Diagnosis of Systemic Lupus Erythematosus
Authors: Kurien B. T. , Scofield R. H.
Published: August 2006

Systemic lupus erythematosus (SLE) is an autoimmune disease that usually develops in young women aged 18–50 years and is characterized by the presence of autoantibodies. Diagnosis is difficult as SLE is a great imitator of other diseases. When SLE is suspected clinically in a patient (involvement of two or more organ systems), an initial laboratory evaluation would be antinuclear antibody (ANA) testing. If ANA is negative, SLE is unlikely and results positive at less than 1:40 strongly argue against SLE. Other explanations for organ system involvement should be pursued. Results positive at greater than 1:40 may merit further evaluation for SLE and at times referral to a rheumatologist for a full SLE evaluation. While the American College of Rheumatology classification criteria for SLE are primarily a tool for research, they may be useful clinically, in that those patients fulfilling four or more criteria are highly likely to have SLE.
Metalloproteinase‐Dependent Control of Thymocyte Differentiation and Proliferation
Authors: Haidl I. D. , Falk I. , Nerz G. , Eichmann K.
Published: August 2006

The development of T cells in the thymus is dependent on interactions between thymocytes and thymic stromal cells, on stimulation by growth factors, and on the binding to and migration along extracellular matrix (ECM) components. As metalloproteinases (MP) are involved in processes such as growth factor release and ECM modelling, we assessed the effect of MP inhibitors on T‐cell development using fetal thymic organ culture systems. MP inhibitors significantly reduced the numbers of CD4/CD8 double‐positive (DP) and mature single‐positive thymocytes generated, correlated with a reduced number of cell cycles between the double‐negative (DN)3 and DP stages. The progression of early thymocyte progenitors through the DN1–4 stages of development was also severely affected, including incomplete upregulation of CD25, decreased DN3 cell numbers, reduced rearrangement of the T‐cell receptor (TCR)‐β locus and expression of intracellular TCR‐β by fewer DN3 cells. When purified DN1 cells were utilized as donor cells in reaggregate thymic organ cultures, essentially no DP thymocytes were produced in the presence of MP inhibitors. The results suggest that MP inhibitors affect the differentiation of developing thymocytes before, and reduce proliferation after, pre‐TCR‐mediated selection.
Microdialysis for Monitoring Inflammation: Efficient Recovery of Cytokines and Anaphylotoxins Provided Optimal Catheter Pore Size and Fluid Velocity Conditions
Authors: Wælgaard L. , Pharo A. , Tønnessen T. I. , Mollnes T. E.
Published: August 2006

Microdialysis emerges as a useful tool to evaluate tissue inflammation in a number of clinical conditions, like sepsis and transplant rejection, but systematic methodological studies are missing. This study was undertaken to determine the recovery of relevant inflammatory mediators using the microdialysis system, comparing microdialysis membranes with two different molecular weight cut‐offs at different flow rates. Twenty and 100 kDa pore sizes CMA microdialysis catheters were investigated using velocities of 0.3, 1.0 and 5.0 μl/min. Reference preparations for cytokines [tumour necrosis factor (TNF)‐α, interleukin (IL)‐1β, IL‐6 and IL‐10; m.w. 17–28 kDa] and chemokines (IL‐8, MCP‐1, IP‐10 and MIG; m.w. 7–11 kDa) were prepared from plasma after incubating human whole blood with lipopolysaccharide. Reference preparation for complement anaphylatoxins (C3a, C4a, C5a; m.w. 9–11 kDa) was prepared by incubating human plasma with heat‐aggregated immunoglobulin G. The reference preparations were quantified for the respective inflammatory molecules and used as medium for the microdialysis procedure. Through the 20 kDa filter only the four chemokines passed, but with low recovery (3–7%) and limited to the 1.0 μl/min velocity. The recovery with the 100 kDa filter was as follows: IL‐1β = 75%, MCP‐1 = 55%, MIG = 50%, IL‐8 = 38%, C4a = 28%, IP‐10 = 22%, C5a = 20%, C3a = 16%, IL‐6 = 11, IL‐10 = 8% and TNF‐α = 4%. The highest recovery for all chemokines and anaphylatoxins were consistently at velocity 1.0 μl/min, whereas IL‐1β and IL‐10 recovered most efficiently at 0.3 μl/min. Thus, microdialysis using catheters with a cut‐off of 100 kDa is a reliable method to detect inflammation as judged by a defined panel of inflammatory markers. These findings may have important implications for future clinical studies.
Inhibition of Monocytic Differentiation by Phosphorylation‐deficient Stat1 is Associated with Impaired Expression of Stat2, ICSBP/IRF8 and C/EBPɛ
Authors: Dimberg A. , Kårehed K. , Nilsson K. , Öberg F.
Published: August 2006

Monocytic differentiation is coordinated through the ordered activation of multiple signalling pathways, controlling transcription of specific subsets of genes that regulate the development of the mature phenotype. To identify key transcription factors involved in this process, we used the human monoblastic U‐937 cell line as a model of monocytic differentiation. U‐937 cells can be differentiated by treatment with all‐trans retinoic acid (ATRA) and 1,25α‐dihydroxycholecalciferol (VitD3), resulting in G0/G1‐arrested cells expressing monocytic surface markers. We have previously shown that ATRA‐induced differentiation and cell cycle arrest specifically requires Stat1 activation, through phosphorylation of tyrosine 701 and serine 727. In this report, we used U‐937 cells expressing phosphorylation‐deficient mutants of Stat1 (Stat1Y701F and Stat1S727A) to determine myeloid‐specific transcription factors that are activated downstream of Stat1 during induced monocytic differentiation. We demonstrate that ATRA‐induced upregulation of Stat2, ICSBP/IRF8 and C/EBPɛ, key transcription factors linked to myelomonocytic differentiation, is selectively impaired in cells expressing mutant Stat1. In contrast, ATRA‐induced expression of PU.1, C/EBPα, C/EBPβ and IRF‐1 was unaffected. Taken together, our data suggest that ATRA‐induced regulation of Stat2, ICSBP and C/EBPɛ is dependent on active Stat1, and that a failure to correctly regulate these transcription factors is associated with the inhibition of monocytic differentiation.
Migration rate limitations on climate change‐induced range shifts in Cape Proteaceae
Authors: Midgley G. F. , Hughes G. O. , Thuiller W. , Rebelo A. G.
Published: August 2006

Modelling of climate change‐induced species range shifts has generally addressed migration limitations inadequately, often assuming ‘null’ migration or instantaneous ‘full’ migration extremes. We describe methods for incorporating simple migration rate assumptions into multispecies modelling, using the Proteaceae of the Cape Floristic Region. Even with optimistic migration assumptions, range loss projections more closely approximate null migration than full migration assumptions. Full migration results were positively skewed by few species with large range increases, an overestimate eliminated by dispersal‐limited migration rate assumptions. Wind‐ and ant/rodent‐dispersed species responded differently to climate change. Initially larger ranges of wind‐dispersed species were more strongly reduced by climate change, despite far greater assumed dispersal distances — we suggest that these well‐dispersed species populate more marginal areas of potential range, causing lower resilience to climatic changes at range margins. Overall, range loss rate slowed with advancing climate change, possibly because species ranges contracted into core areas most resilient to climate change. Thus, a consideration of simple dynamics of range change (rather than single step, present–future comparisons of range) provide new insights relevant for conservation strategies, in particular, and for guiding monitoring efforts to detect and gauge the impacts of climate change on natural populations.
Telemedicine‐friendly, portable tonometers: an evaluation for intraocular pressure screening
Authors: Kumar Sajeesh , Middlemiss Catherine , Bulsara Max , Guibilato Antonio , Morgan William , Tay‐Kearney Mei‐Ling , Constable Ian J , Yogesan Kanagasingam
Published: August 2006

Abstract

Purpose:  To evaluate the intraocular pressure (IOP) readings from two portable, telemedicine‐friendly tonometers for suitability in glaucoma screening.

Methods:  213 eyes of 107 consenting patients attending an eye clinic were tested with an I‐care tonometer and a Pulsair‐Easy Eye puff‐air tonometer. Gold standard IOP was measured with a Goldmann applanation tonometer (GAT). Effect of central corneal thickness, anterior chamber depth and refractive errors on IOP measurements were also analysed.

Results:  The mean difference of IOP by GAT and both the portable tonometers was ± 2.2 mmHg. The analysis indicates minimal difference between IOP readings of both the portable tonometers. The mean difference between two consecutive readings by I‐care was 0.01 mmHg. Using 21 mmHg as a threshold for suspected glaucoma, both the portable digital tonometers reported a sensitivity of 38% and specificity of >95%. In the subjects studied, central corneal thickness had statistically significant influence on IOP measurements while refractive errors and anterior chamber depth had no significant influence on IOP measurements with any tonometry.

Conclusion:  The IOP readings by both portable tonometers are comparable and were within clinically acceptable range from GAT. These portable tonometers are useful tools for IOP screening.
Trabeculectomy with brief exposure to mitomycin C
Authors: Ben Simon Guy J , Glovinsky Yoseph
Published: August 2006

Abstract

Background:  To evaluate the safety and efficacy of primary trabeculectomy with brief exposure (15 s) to mitomycin C (MMC) (0.4 mg/mL).

Methods:  Medical record review of all patients who underwent primary trabeculectomy with brief exposure to MMC at the Goldschleger Eye Institute in a 4‐year period was performed.

Results:  Sixty‐three patients (35 men, mean age of 55 years) underwent trabeculectomy with brief exposure to MMC. Intraocular pressure (IOP) decreased a mean ± standard deviation of 17.9 ± 9.6 mmHg from 30.4 ± 9.5 mmHg preoperatively to 12.5 ± 6.2 mmHg postoperatively after a mean follow up of 18.3 months (P < 0.001). Number of antiglaucoma medications decreased from 2.9 ± 1.1 preoperatively to 0.2 ± 0.4 postoperatively (P < 0.001, paired samples t‐test). Complete success, defined as IOP < 18 mmHg without antiglaucoma medication, was achieved in 46 patients (73%) and qualified success, defined as IOP ≤ 21 mmHg with or without antiglaucoma medications, was achieved in 59 patients (93.7%). Thirty‐eight patients (60%) had a final IOP < 15 mmHg with no glaucoma medications at the end of follow up. Needle revision was required in four patients (6.3%) and repeated trabeculectomy was performed in three patients (4.8%). Four patients had an IOP of less than 6 mmHg at the end of follow‐up period (three had final IOP of 5 mmHg and one of 4 mmHg); these patients had an average larger bleb size (2.8 ± 1.3).

Conclusions:  Trabeculectomy with brief (15 s) exposure to MMC 0.4 mg/mL is safe and effective in lowering IOP in this group of patients, and results in low rate of postoperative complications. Success is comparable to reported data with longer exposure durations to antimetabolites.
An assessment of recycled spectacles donated to a developing country
Authors: Ramke Jacqueline , Du Toit Renee , Brian Garry
Published: August 2006

Abstract

Background:  A rapid assessment methodology was used to determine the suitability of donated recycled spectacles for the Pacific nation of Tuvalu.

Methods:  Spectacles (102) from a donated cache were examined. Those with astigmatism of >1.00 D, anisometropia of >0.50 D, significant central lens scratches, broken frame, poor cosmetic fit and comfort, or unsuitable frame appearance were excluded. The refractive errors (≥ ±0.50 D distance or near) of 320 Tuvaluans were determined.

Results:  Of the spectacles, 62.7% had >1.00 DC and/or >0.50 D anisometropia, 30% were broken and/or scratched and 50% were uncomfortable or cosmetically unacceptable. Only 13% were optically satisfactory, physically intact, and cosmetically appropriate. Of the people, 8.8% had >1.00 DC and/or >0.50 D anisometropia, requiring custom‐made spectacles. A further 8.1% needed a −0.50 to −2.00 DS correction, for which there were no spectacles in this cache. For the other 83.1% (266), if the cache contained at least 5538 spectacles, each would eventually find a suitable pair.

Conclusion:  If the scheme to Tuvalu is typical, refractive error will remain largely uncorrected if only donated recycled spectacles are available. No amount of efficiency and effectiveness in the delivery chain can justify the output and outcome of this recycling scheme.
Proliferation of spermatogonial stem cells and spermatogenesis in vitro
Authors: OGAWA TAKEHIKO , KITA KAORU , KUBOTA YOSHINOBU
Published: August 2006

Detection of spermatogonial stem cells (SSC) became possible 10 years ago, with the transplantation of germ cells into the seminiferous tubules of mice. Using this assay system, attempts to maintain and expand SSC in vitro finally bore fruit. Gonocytes from neonatal mice and spermatogonial stem cells from adult mice were plated on feeder cells in a medium supplemented with Glial cell line‐derived neurotrophic factor (GDNF) along with certain other factors. The germ cells that emerged under such conditions, named germline stem (GS) cells, proliferated exponentially through self‐renewing division. GS cells in vitro show features of differentiation as well. Some expressed c‐kit, which is a cell surface marker of differentiating spermatogonia. Therefore, it seems that GS cells undergo both self‐renewing and differentiating cell divisions in vitro. There is a century of history behind attempts to reproduce spermatogenesis in vitro and significant progress has been made. Nonetheless, there are few established culture‐based protocols for recreating spermatogenesis in vitro. GS cells would be an ideal starting material in this regard. (Reprod Med Biol 2006; 5: 169–174)
Prediction of candidates for seminal tract reconstructive surgery among patients with clinically suspected idiopathic or inflammatory obstructive azoospermia
Authors: TANAKA TOSHIAKI , ITOH NAOKI , SASAO TAKUMI , MAEDA TOSHIHIRO , TSUKAMOTO TAIJI , KAMIYA HIROFUMI
Published: August 2006

Background and Aim:  We reviewed the findings of scrotal exploration, histological examination and clinical parameters in patients with clinically suspected idiopathic or inflammatory obstructive azoospermia without confirmation by isolated testis biopsy in advance.

Methods:  The present study included 27 patients who underwent scrotal exploration for the purpose of vasoepididymostomy, with simultaneous testicular sperm extraction.

Results:  Sperm in the epididymis was proven in 11 patients (40.7%). In two of these patients, the vas deferens was obstructed on the seminal vesicle side. Histologically, normal spermatogenesis was seen in all patients. The 16 (59.2%) patients with no sperm in the epididymis included two with normal spermatogenesis. Serum follicle stimulating hormone (FSH) levels were significantly higher in men with no sperm in the epididymis in contrast to those in men with sperm proven in the epididymis (P = 0.0057). By using a cut‐off point of 6.02 mIU/mL, serum FSH can predict the existence of sperm in the epididymis, with a sensitivity of 81.8%, a specificity of 81.2% and a positive predictive value of 75.0%.

Conclusion:  No more than a third of the patients in the present study who had clinically suspected obstructive azoospermia were actual candidates for vasoepidydimostomy. A serum FSH level cut‐off point of 6.02 mIU/mL might be useful to determine its indication. (Reprod Med Biol 2006; 5: 211–214)
Influence of the hypogonadism (hgn) locus on female reproduction and ovarian development in an altered genetic background
Authors: SUZUKI HIROETSU , DAIGO KUMI , OKADA MIKA , YAGI MIO , NAKAMIYA EIJIRO , SAITO KENICHI , SUZUKI KATSUSHI
Published: August 2006

Background and Aims:  The hypogonadic rat (hgn/hgn) shows male sterility controlled by a single recessive gene hgn. The hgn/hgn females detected by the presence of renal hypoplasia in the HGN inbred strain show a reduced fertility. Recently, the gene responsible for male hypogonadism was mapped on chromosome 10 by a linkage analysis using only male backcross progeny. Because backcross females could not be categorized as affected or normal because of variations in their renal sizes, we could not examine female fertility in the backcross progeny. In the present experiment, we examined whether the gene mapped on rat chromosome 10 has any influences on female reproduction and ovarian development.

Methods:  The assumptive hgn/hgn females were identified in the backcross progeny by microsatellite markers closely linked to the hgn locus. Postnatal body growth, the weights of reproductive organs, estrus cycle and ovarian histology were examined. In addition, backcross embryos were genotyped, and their body growth and ovarian development was examined.

Results:  The hgn/hgn females showed growth retardation, a short reproductive life and an abnormal ovarian histology as adults. Regarding embryonic development, hgn/hgn females showed body growth retardation and ovarian hypoplasia.

Conclusion:  The mutation of the hgn mapped on chromosome 10 causes not only male sterility but also female reduced fertility related to ovarian hypoplasia beyond the altered genetic background. (Reprod Med Biol 2006; 5: 227–234)
Reliability analysis in fracture mechanics using the first‐order reliability method and Monte Carlo simulation
Authors: PUATATSANANON W. , SAOUMA V. E.
Published: August 2006

The development of a Windows‐based framework to undertake probabilistic fracture mechanics studies is reported. For a selective library of standard case problems, the reliability index of critical and sub‐critical (fatigue) problems with stochastic definition is evaluated. Both first‐order reliability method (FORM) as well as and Monte Carlo simulation method (MCS) techniques are used in critical crack growth, and only MCS is adopted for fatigue problems.

Numerical predictions for the stress intensity factors (SIF) were validated with NASA/FLAGRO and reliability predictions were validated with both RELTRAN and VaP.

With the advent of powerful and inexpensive personal computer, and the user‐friendliness of graphical user interface, programs such as the one developed will indeed make it possible for engineer to correctly account for the stochastic nature of most fracture problems they are confronted with.
Aspects of rapid crack propagation in silicon
Authors: SHERMAN D.
Published: August 2006

Fracture experiments with silicon specimens in recent years have shown the need for a new approach to the analysis of rapidly propagating cracks in single crystals. Behaviour and phenomena have been revealed that fracture in these materials is rather different from the fracture of both amorphous and polycrystalline materials. We show that continuum mechanics is insufficient for analyzing crack propagation in single crystals since it is unable to consider atomistic‐scale phenomena. Accordingly, we describe basic phenomena associated with rapid crack propagation in silicon: (i) anisotropic velocity‐dependent R‐curve behaviour, as a key phenomenon dictating atomistic scale behaviour, (ii) crack deflection from one cleavage plane to another as a mesoscopic scale phenomenon in single‐crystal fracture, (iii) the Rayleigh surface wave speed as the limiting crack tip velocity is re‐examined, (vi) the lowest crack velocity in brittle crystals is examined, and finally (v) the interaction between crack path and preferred cleavage planes in single crystals is depicted.
Correlation of oxygen delivery with central venous oxygen saturation, mean arterial pressure and heart rate in piglets
Authors: OSTHAUS WILHELM A. , HUBER DIRK , BECK CARSTEN , ROEHLER ANJA , MARX GERNOT , HECKER HARTMUT , SÜMPELMANN ROBERT
Published: August 2006

Background:  Accurate assessment and monitoring of the cardiocirculatory function is essential during major pediatric and pediatric cardiac surgery. Invasive monitoring of cardiac output and oxygen delivery (DO2) is expensive and sometimes associated with adverse events. Measurement of central venous oxygen saturation (ScvO2) is less invasive and may reflect the DO2. Therefore, we investigated the correlation of ScvO2 with cardiac index (CI) and DO2 and in comparison the more common monitored parameters heart rate (HR) and mean arterial pressure (MAP) with DO2 in an animal experimental setting.

Methods:  In five fasted, anesthetized and mechanically ventilated piglets CI (transpulmonary thermodilution), venous and arterial blood gases, HR and MAP was measured during normal conditions, volume loading, inotropic support, and exsanguination.

Results:  In the five piglets 168 measurements could be performed. In a wide hemodynamic range (CI 22–335 ml·kg−1min−1) we found significant correlations of ScvO2 with DO2 (r2 = 0.91, P < 0.0001) and CI (r2 = 0.88, P < 0.0001) and also between DO2 and MAP (r = 0.86, P < 0.0001) and HR (r = 0.19, P < 0.05).

Conclusions:  ScvO2 is a better parameter for indirect estimation of DO2 than MAP and heart rate. Measurement of ScvO2 is simple and does not necessitate additional invasive techniques. In the clinical setting ScvO2 should be used in combination with other standard vital parameters, i.e. MAP, central venous pressure, lactate, base excess, and urine output.
Evaluating fair trade consumption: politics, defetishization and producer participation
Authors: Lyon Sarah
Published: August 2006

This paper combines a critical review of the scholarly literature on fair trade with an analysis of data gathered during 19 months of ethnographic research conducted between 2001 and 2003 among the members of a Guatemalan fair trade coffee co‐operative and fair trade coffee roasters and advocates in the US. It explores three common claims made about fair trade consumption that: first, fair trade consumption emerges from the political choices and conscious reflexivity of Northern consumers; second, it defetishizes coffee by revealing the social and environmental conditions of the coffee production; and third, it forges equitable trade relationships between producers and consumers. While the research results demonstrate that there is some validity to each of the three claims, they also highlight two negative trends: the reinforcement of producer–consumer differences and low levels of farmer participation in fair trade networks beyond the realm of commodity production. In conclusion, the paper argues that overstating the exceptional nature of fair trade consumption weakens the market’s transformative potential. In order to nurture equitable trade partnerships fair trade must expand to accommodate a substantially higher degree of producer participation in administrative decision making and goal setting.
Ambiguous framings of political consumerism: means or end, product or process orientation?
Authors: Klintman Mikael
Published: August 2006

For dealing with various societal problems, ‘political’/‘ethical’/‘responsible’ consumerism is often discussed as an effective democratic and participatory tool. However, political consumerism – along with its tools, such as product labelling – is often conceived and discussed in oversimplified ways. Instead, the tension between scientific complexity, knowledge uncertainty and a codified, standardized label involves extensive political strategy, interest conflicts and simplified framings of the consumers’ roles as political decision makers. The purpose of this paper is to analyse how criteria for organic food labelling have been simplified, or framed, within various versions of political consumerism in policy debates. The more general purpose is to examine variations of what consumerism may entail theoretically and practically. Examples are chosen of organic food labelling in the US. The analysis is based on framing theory. The first distinction is made between framings surrounding the extrinsic and intrinsic values of consumerism (i.e. consumer empowerment towards an external goal, or as an overriding principle of democracy). The second distinction is between product‐ and process‐oriented consumerism (i.e. consumer empowerment with regard to the purchased goods or concerning the ‘invisible’ production and disposal processes). These distinctions may facilitate critical examinations of criteria, processes and communication of consumer‐related policies.
Conservation Biology, Genetically Modified Organisms, and the Biosafety Protocol
Authors: HILL RYAN , SENDASHONGA CYRIE
Published: August 2006

Abstract:  Concerns have been raised regarding the potential adverse effects on biological diversity of the use of living modified organisms (LMOs, which are commonly known by similar terms such as genetically modified organisms). At the international level these concerns are addressed in part by an agreement known as the Cartagena Protocol on Biosafety and include potential toxic effects of insect‐resistant crops on nontarget organisms and potential ecological effects of gene flow from modified crops, fish, microorganisms, or insects to wild species or counterparts. We reviewed the protocol's main provisions, including those dealing with risk assessment and risk management, decision making on imports, documentation accompanying shipments, and liability resulting from damages caused by LMOs. A medium‐term program of work has been adopted by the parties, which includes the potential contribution of conservation biologists to delivering capacity building, developing risk assessment guidance, evaluating mechanisms of potential ecological damages from LMOs, and other issues. Conservation biologists and other experts have opportunities to influence the negotiations and implementation of the protocol by providing inputs at meetings, offering expertise to governments and organizations, and participating in or developing relevant projects and initiatives. Involvement of conservation biologists in the implementation and further development of the protocol would contribute to its effectiveness.
Decline in Relative Abundance of Bottlenose Dolphins Exposed to Long‐Term Disturbance
Authors: BEJDER LARS , SAMUELS AMY , WHITEHEAD HAL , GALES NICK , MANN JANET , CONNOR RICHARD , HEITHAUS MIKE , WATSON‐CAPPS JANA , FLAHERTY CINDY , KRÜTZEN MICHAEL
Published: August 2006

Abstract:  Studies evaluating effects of human activity on wildlife typically emphasize short‐term behavioral responses from which it is difficult to infer biological significance or formulate plans to mitigate harmful impacts. Based on decades of detailed behavioral records, we evaluated long‐term impacts of vessel activity on bottlenose dolphins (Tursiops sp.) in Shark Bay, Australia. We compared dolphin abundance within adjacent 36‐km2 tourism and control sites, over three consecutive 4.5‐year periods wherein research activity was relatively constant but tourism levels increased from zero, to one, to two dolphin‐watching operators. A nonlinear logistic model demonstrated that there was no difference in dolphin abundance between periods with no tourism and periods in which one operator offered tours. As the number of tour operators increased to two, there was a significant average decline in dolphin abundance (14.9%; 95% CI =−20.8 to −8.23), approximating a decline of one per seven individuals. Concurrently, within the control site, the average increase in dolphin abundance was not significant (8.5%; 95% CI =−4.0 to +16.7). Given the substantially greater presence and proximity of tour vessels to dolphins relative to research vessels, tour‐vessel activity contributed more to declining dolphin numbers within the tourism site than research vessels. Although this trend may not jeopardize the large, genetically diverse dolphin population of Shark Bay, the decline is unlikely to be sustainable for local dolphin tourism. A similar decline would be devastating for small, closed, resident, or endangered cetacean populations. The substantial effect of tour vessels on dolphin abundance in a region of low‐level tourism calls into question the presumption that dolphin‐watching tourism is benign.
Hippocampal Cell Loss in Posttraumatic Human Epilepsy
Authors: Swartz Barbara E. , Houser Carolyn R. , Tomiyasu Uwami , Walsh Gregory O. , DeSalles Antonio , Rich J. Ronald , Delgado‐Escueta Antonio
Published: August 2006

Summary:  Purpose: We performed this study to determine whether significant head trauma in human adults can result in hippocampal cell loss, particularly in hilar (polymorph) and CA3 neurons, similar to that observed in animal models of traumatic brain injury. We examined the incidence of hippocampal pathology and its relation to temporal neocortical pathology, neuronal reorganization, and other variables.

Methods: Twenty‐one of 200 sequential temporal lobectomies had only trauma as a risk factor for epilepsy. Tissue specimens from temporal neocortex and hippocampus were stained with glial fibrillary acidic protein (GFAP) and hematoxylin and eosin (H&E). Eleven hippocampal specimens had additional analysis of neuronal distributions by using cresyl violet and immunolabeling of a neuron‐specific nuclear protein.

Results: The median age at onset of trauma was 19 years, the median time between trauma and onset of seizures was 2 years, and the median epilepsy duration was 16 years. The length of the latent period was inversely related to the age at the time of trauma (r= 0.75; Spearman). The neocortex showed gliosis in all specimens, with hemosiderosis (n = 8) or heterotopias (n = 6) in some, a distribution differing from chance (p = 0.02; Fisher). Hippocampal neuronal loss was found in 94% of specimens, and all of these had cell loss in the polymorph (hilar) region of the dentate gyrus. Hilar cell loss ranged from mild, when cell loss was confined to the hilus, to severe, when cell loss extended into CA3 and CA1. Some degree of mossy fiber sprouting was found in the dentate gyrus of all 10 specimens in which it was evaluated. Granule cell dispersion (n = 4) was seen only in specimens with moderate to severe neuronal loss.

Conclusions: Neocortical pathology was universally present after trauma. Neuronal loss in the hilar region was the most consistent finding in the hippocampal formation, similar to that found in the fluid‐percussion model of traumatic head injury. These findings support the idea that head trauma can induce hippocampal epilepsy in humans in the absence of other known risk factors.
TEMPERATURE AND SALINITY EFFECTS ON GROWTH OF A NON‐CHAIN‐FORMING STRAIN OF FYMNODINIUM CATENATUM (DINOOHYCEAE) ESTABLISHED FROM A CYST FROM RECENT SEDIMENTS IN THE SOUND (øRESUND), DENMARK1
Authors: Ellegaard Marianne , Christensen Niels F. , Meostrup Øjvind
Published: August 2006

The athecate, marine dinoflagellate Gymnodinium catenatum Graham 1943 was cultured from a resting cyst found in sediment samples from The Sound, Denmark. Gymnodinium catenatum has not previously been registered alive in Danish waters, although fossilized cysts have been found in old sediments. The description (morphology and ultrastructure) of the strain established from the cyst complied with earlier studies of G. catenatum with the exception that chains longer than two cells were never see. Fitting the growth rates of the motile stage of G. catenatum to a linear model showed a signified influence of temperature and salinity. Maximal division rate was 0.4 div‐day−1 at 20–25°C and 20% salinity. Gymnodinium catenatum causes paralytic shellfish poisoning in other parts of the world, but the toxicity of the Danish strain has not been determined. Possible explanations for the presence of G. catenatum in Danish waters ware discussed.
ROLE OF ENCYSTMENT AND EXCYSTMENT OFPERIDINIUM BIPESF.OCCULATUM(DINOPHYCEAE) IN FRESH WATER RED TIDES IN LAKE KIZAKI, JAPAN1
Authors: Park Ho‐Dong , Hayashi Hidetake
Published: August 2006

The encystment flux ofPeridinium bipesf. occulatum (Dinophyceae) was investigated with sediment traps from 1968 to 1990 in Lake Kazki. Cysts ofP. bipeswere formed throughout the blooms, Encystment flux ofP. bipesin the pelagic zone was usually lower than those at shallow sites, and the density ofP. bipescysts in lake sediment was higher in the shallow region than in the pelagic zone. However, in the shallower region, The concentration ofP. bipescysts varied widely, possibly due to high rates of encystment and excystment.

Peridinium bipesencystment occurred between 15° and 25° C in the laboratory, with very little cyst formation below 10°C. Though cyst formation was observed in continous darkness, the rate increased with irradiance. Under continuous darkness, no excystment was observed at any temperature from 5° to 25° C. Eighty‐one percent of the cysts illuminated at 105 μE m−2s−1excysted after 13 days incubation at 15° C, and lower irradiances decreased germination success. Results from laboratory experiments suggest that light is a critical factor in the germination ofP. bipescysts. Bottom depth thus can have a significant effect on germination because cysts only can excyst from depths where light is sufficient. The shallow region of the lake is thus very important as a seed bed forP. bipesduring early spring. Cyst deposited in deeper waters may not ever germinate unless they are resuspended and transported to shallow areas where light reaches the bottom.
PHYSIOLOGICAL AND PHOTOSYNTHETIC CHANGES DURING THE FORMATION OF RED APLANOSPORES IN THE CHILOROPHYTE HAEMATOCOCCUS PLUVIALIS1
Authors: Zlotnik (Shmerler) Ita , Sukenik Assaf , Dubinsky Zvy
Published: August 2006

Changes in physiological and photosynthetic parameters were followed in the freshwater chorophyte Haematococcus pluvialis Flotow (Volvocales) during the transformation of green vegetative cells to red aplanospores.Formation of aplanospores was induced by exposure to a nitrogen‐deficient medium. In spite of an increase in cellular volume (from 6.6 to 41 pL) and amassive accumulation of astaxanthin, chlorophyll content of the mature aplanospore decreased only slightly (from 16 to 14.8 pg'cell−1)as compared to the vegetative cell. Aplanospore formation was characterized by a gradual reduction in the maximal photosynthetic rate and increases in the photosynthetic quantum requirement and minimal turnover time for photosynthetic O2 evolution.Respiration rate increased (4.2 times)and excretion rate decreased (up to 8.8 times) during aplanospore formation. Measurements of photosynthetic unit “size” and estimation of the cellular content of photosystem II reaction centers suggest that the photosynthetic complex remains relatively centers stable during the formation process and in the mature aplanospore.A functional relationship between the describe changes in the physiology of the cells and their photosynthetic parameters is proposed.
LIGHT AND ELECTRON MICROSCOPICAL OBSERVATIONS OF THE DINOFLAGELLATE ACTIMSCUS PESTASTERIAS (DINOPHYCEAE)1
Authors: Hansen Gert
Published: August 2006

I examined the heterotrophic non‐armored dinoflaget‐late Actiniscus pentasterias (Ehrenberg) Ehrenberg by light and electron microscopy. Actiniscus pentasterias contains an internal skeleton consisting of two star‐like siliceous elements. Special emphasis is given to the flagellar apparatus, the nucleus, and a new type of extrusome, named a docidosome. A three dimensional model of the flagerllar apparatus includes a fibrous nuclear connnective, a posterior striated root, and a dorsal striated component of the longitudinal microtabular root. The nucleus is surrounded by a conspicuous fibrous lamina, also visible in the light microscope. The nuclear pores are situated in annulated invaginations of the nuclear envelope, increasing the nuclear surface area by 15–25%. The docidosomes are rod‐shaped membrane‐bound structures that terminate in a distinct proximal head. They show very complex substructure, consisting of an inner medulla with highly ordered paired ribbons and an outer cortex.
SCRIPPSIELLA VELELLAE SP. NOV. (PERIDINIALES) AND GLOEOKINIUM VISCUM SP. NOV. (PHYTODINIALES), DINOFLAGELLATE SYMBIONTS OF TWO HYDROZOANS (CNIDIARIA)1,2
Authors: Banaszak Anastazia T. , Iglestas‐Prieto Roberto , Trench Robert K.
Published: August 2006

The alga symbiotic with the “By the Wind Sailor”Vellela vellela L. (Hydrozoa, Chondrophora) collected off the coast of California, and the alga symbiotic with the hydrocoral Millepora dichotoma Forskal (Hydrozoa, Milleporina) from the Gulf of Aqaba, were isolated and brought into unialgal, axenic culture. Based on light microscopy and ultrastructure analyses by transmission and scanning electron microscopy, the algal population from V. velella is described as Scrippsiella velellae sp. nov. (Peridiniales). The algal population from the dark morph of M. dichotoma is decribed as Gloedinium viscum sp. nov. (Phytodiniales). These are the first descriptions of symbiotic dinoflagellate belonging to the orders Peridiniales and Phytodiniates. When viewed with descriptions of symbiotic dinoglagellates belonging to the Prorocentrales and Gymnodiniales, the evidence currently points to seven genera in four orders of dinoflagellates having representatives that have entered a symbiotic mode of existence.
MACROALGAL RECRUITMENT IN A HIGH MARSH CREEK OF NORTH INLET ESTUARY, SOUTH CAROLINA1
Authors: Flavier Albert B. , Zingmark Richard G.
Published: August 2006

The temporal and spatial variability in recruitment patterns of macroalgae were stuided by evaluating the appearace of propagules on marble tiles set over a depth gradient in a high marsh tidal creek in North Inlet Estuary, South Carolina. Ulvoids and Porphyra occurred over a wide range of depths in the intertidal zone unlike Ectocarpus and members of the Florideophycease, which grew over a more restricted zone. Ulvoid propagules were the most abundant, attaining maximum densities at 0 and ‐15 cm mean low water (MLW) at all seasons except winter. In summer, coincident with high tubbidity, ulvoid densities decreased at ‐15 cm MLW but not in other seasons. Ulvoid densities at 0 MLW were depressed in January, February was preceded with the lowest recoreded temperatures and salinities during the study period, while the decrease in July was preceded by the highest recorded temperature. The number of taxa was highest in April and September, representing winter‐spring and summer‐fall transition periods, respecitively. The biomass of adult forms was higher on the tiles than on naturally occurring substrala, perhaps due to lack of stable suitable substrata in the field. Inhibition of subsequent recruitment by initial recreuitment was evident only on tiles submerged in October. The initial recruitment pattern of Porphyra rosengurtii coll et Cox and Ectocarpus siliculosus (Dillwyn) Lyngbye seem to determine the biomass distribution of adult forms, while that of ulvoids may be altered later by other factors. The considerable decrease in the number of adult forms compared to the initial denisties of propagules indicales high juvenile mortalities.