bluuebunny/crossref_metadata_2025 huggingface dataset:
Reduced chilling tolerance in elongating cucumber seedling radicles is related to their reduced antioxidant enzyme and DPPH‐radical scavenging activity
Authors: Kang Ho‐Min , Saltveit Mikal E.
Published: March 2003

Cucumber seedling radicles become more chilling sensitive as they elongate. Chilling seedlings with radicles 20 mm long for 48 h at 2.5°C inhibited subsequent growth by 36%, while it reduced the growth of 70 mm‐long radicles by 63%. Although the growth rate of non‐chilled cucumber radicles at 25°C is constant from 20 to 80 mm, tissue viability [i.e. reduction of TTC (2,3,5‐triphenyltetrazolium chloride) to formazan] and DPPH (α,α‐diphenyl‐β‐picrylhydrazyl) radical scavenging activity of apical tissue declines as radicles elongate from 20 to 80 mm in length. TTC reduction, DPPH‐radical scavenging activity and protein content of apical tissue were higher in 20 than in 70 mm radicles immediately after chilling and after an additional 48 h of growth at 25°C. Catalase (CAT; EC 1.11.1.6) and ascorbate peroxidase (APX; EC 1.11.1.11) activity was higher in the apical tissue of 20 than in 70 mm radicles before chilling. Immediately after chilling and after an additional 48 h at 25°C, superoxide dismutase (SOD; EC 1.15.1.1), glutathione reductase (GR; EC 1.6.4.2), and guaiacol peroxidase (GPX; EC 1.11.1.7) activity increased more rapidly in 70 mm radicles than in 20 mm radicles (SOD, GR, and GPX activity in 70 mm radicles was 1.5‐, 1.9‐ and 8.6‐fold higher, respectively, than in 20 mm radicles). However, APX and CAT activity in 20 mm radicles were always higher than in 70 mm radicles. Growth after chilling enhanced the activity of all antioxidant enzymes compared to that found in non‐chilled tissue; however, CAT activity in 70 mm radicles did not recover to levels found in non‐chilled tissue. Higher levels of CAT, APX and DPPH‐radical scavenging activity are correlated with higher chilling tolerance of 20 mm‐long cucumber radicles compared to 70 mm‐long radicles.
Protective role of exogenous polyamines on salinity‐stressed rice (Oryza sativa) plants
Authors: Chattopadhayay Manas Kumar , Tiwari Budhi Sagar , Chattopadhyay Gouri , Bose Anindita , Sengupta Dibyendu Narayan , Ghosh Bharati
Published: March 2003

Salt‐tolerant Pokkali rice plants accumulate higher polyamines (PAs) such as spermidine (Spd) and spermine (Spm) in response to salinity stress, while the sensitive cultivarM‐1–48 is unable to maintain high titres of these PAs under similar conditions. The effects of the triamine Spd and the tetramine Spm on physiological and biochemical changes in 12‐day‐old rice seedlings were investigated during salinity stress to determine whether they could protect the sensitive plants from stress effects. At physiological concentrations Spd and Spm significantly prevented the leakage of electrolytes and amino acids from roots and shoots induced by salinity stress. To different degrees they also prevented chlorophyll loss, inhibition of photochemical reactions of photosynthesis as well as downregulation of chloroplast‐encoded genes like psbA, psbB, psbE and rbcL, indicating a positive correlation between salt tolerance and accumulation of higher PAs in rice. The inhibitory effect of salinity stress and its reversal by exogenous PAs were more pronounced in the salt‐sensitiveM‐1–48 plants than in the tolerant Pokkali plants.
Enhancement of photosynthesis in Sorghum bicolor by ultraviolet radiation
Authors: Johnson Gregory A. , Day Thomas A.
Published: March 2003

We assessed the influence of ultraviolet radiation (UV) on net photosynthetic CO2 assimilation rate (Pn) in Sorghum bicolor, with particular attention to examining whether UV can enhance Pn via direct absorption of UV and absorption of UV‐induced blue fluorescence by photosynthetic pigments. A polychromatic UV response spectrum of leaves was constructed by measuring Pn under different UV supplements using filters that had sharp transmission cut‐offs from 280 to 382 nm, against a background of non‐saturating visible light. When the abaxial surface was irradiated, Pn averaged 4.6% higher with the UV supplement that cut‐off UV at 311 nm, compared to lower and higher UV wavelength supplements. This former supplement differed from higher wavelength supplements by primarily providing more UV between 320 and 350 nm. To assess the possibility of direct absorption of UV by photosynthetic pigments, we measured the absorbance of extracted chlorophylls. Chlorophyll a had absorbance peaks at 340 and 389 nm that were 49 and 72% of that at the sorét peak. Chlorophyll b had absorbance peaks at 315 and 346 nm that were both 35% of that at the sorét peak. Since the epidermis transmits some UV, the strong UV absorbance of chlorophyll implies a potential role for irradiance beyond the bounds of the conventionally defined photosynthetically active radiation waveband (400–700 nm). To assess the role of absorption of UV‐induced blue fluorescence, we measured the UV‐induced fluorescence excitation and emission spectra of leaves. Abaxial excitation peaked at 328 nm, while emission peaked at 446 nm. In this analysis, we used our abaxial fluorescence excitation spectrum and the UV photosynthetic inhibition spectrum of Caldwell et al. (1986) to weight the UV irradiance with each cut‐off filter, thereby estimating the potential contribution of UV‐induced blue fluorescence to photosynthesis and the inhibitory effects of UV irradiance on photosynthesis, respectively. With a non‐saturating visible background, we estimate that the absorption of UV‐induced blue fluorescence and the direct absorption of UV by photosynthetic pigments maximally enhanced photosynthesis by about 1% each with the UV supplement that cut‐off UV at 311 nm. We suggest that a portion of the incident UV on the S. bicolor leaves was used to drive photosynthesis.
Casparian strips in needles of Pinus bungeana: isolation and chemical characterization
Authors: Wu Xiaoqin , Lin Jinxing , Zhu Jinmao , Hu Yuxi , Hartmann Klaus , Schreiber Lukas
Published: March 2003

By using cell wall degrading enzymes, Casparian strips were for the first time isolated from Pinus bungeana needle endodermis. They appeared as a fine network, similar to those isolated from roots. Fourier transform infrared spectroscopic analysis provided evidence that the Casparian strips were impregnated with lignin, suberin, cellulose and cell wall proteins.
Diagnostic approaches to cytomegalovirus infection in bone marrow and organ transplantation
Authors: Griffiths P.D. , Cope A.V. , Hassan‐Walker A.F. , Emery V.C.
Published: March 2003

Cytomegalovirus (CMV) continues to be a clinical problem, impairing the overall success rate of transplantation, either through direct involvement of a variety of end‐organs or by inducing indirect effects such as graft rejection. We review here how the virus manages to evade host immune responses and replicate extensively in allograft recipients. Recent studies show that the quantity of CMV (viral load) is related directly to the development of CMV disease. We review how clinically significant levels of CMV viral load can be defined and summarize the results of studies showing that a high CMV viral load is the major determinant of CMV disease, explaining the previously reported risk factors of pre‐transplant serostatus and the post‐transplant detection of CMV viremia. Note
Preemptive treatment approach to cytomegalovirus (CMV) infection in solid organ transplant patients: relationship between compliance with the guidelines and prevention of CMV morbidity
Authors: Künzle N. , Petignat C. , Francioli P. , Vogel G. , Seydoux C. , Corpataux J.‐M. , Sahli R. , Meylan P.R.A.
Published: March 2003

Cytomegalovirus (CMV) remains a major cause of morbidity in solid organ transplant patients. In order to reduce CMV morbidity, we designed a program of routine virological monitoring that included throat and urine CMV shell vial culture, along with peripheral blood leukocyte (PBL) shell vial quantitative culture for 12 weeks post‐transplantation, as well as 8 weeks after treatment for acute rejection. The program also included preemptive ganciclovir treatment for those patients with the highest risk of developing CMV disease, i.e., with either high‐level viremia (>10 infectious units [IU]/106 PBL) or low‐level viremia (<10 IU/106 PBL) and either D+/R− CMV serostatus or treatment for graft rejection.

During 1995–96, 90 solid organ transplant recipients (39 kidneys, 28 livers, and 23 hearts) were followed up. A total of 60 CMV infection episodes occurred in 45 patients. Seventeen episodes were symptomatic. Of 26 episodes managed according to the program, only 4 presented with CMV disease and none died. No patient treated preemptively for asymptomatic infection developed disease. In contrast, among 21 episodes managed in non‐compliance with the program (i.e., the monitoring was not performed or preemptive treatment was not initiated despite a high risk of developing CMV disease), 12 episodes turned into symptomatic infection (P=0.0048 compared to patients treated preemptively), and 2 deaths possibly related to CMV were recorded. This difference could not be explained by an increased proportion of D+/R− patients or an increased incidence of rejection among patients with episodes treated in non‐compliance with the program. Our data identify compliance with guidelines as an important factor in effectively reducing CMV morbidity through preemptive treatment, and suggest that the complexity of the preemptive approach may represent an important obstacle to the successful prevention of CMV morbidity by this approach in the regular healthcare setting.
Community respiratory virus infections following lung transplantation
Authors: Billings J.L. , Hertz M.I. , Wendt C.H.
Published: March 2003

Abstract: Respiratory infections remain a significant cause of morbidity and mortality after lung transplantation. In addition to cytomegalovirus, the community respiratory viruses such as respiratory syncytial virus (RSV), parainfluenza virus (PIV), influenza virus, and adenovirus, are important causes of infection in transplant recipients, often involve the lower respiratory tract, and may be associated with significant morbidity and mortality. In this review, we summarize the current state of knowledge regarding the epidemiology, clinical manifestations, diagnosis, treatment and outcomes associated with RSV, PIV, influenza virus, and adenovirus infections in lung transplant recipients.
Fetal porcine thymus engraftment, survival and CD4 reconstitution in αGal‐KO mice is impaired in the presence of high levels of antibodies against αGal
Authors: Rodriguez‐Barbosa Jose‐Ignacio , Zhao Yong , Houser Stuart , Zhao Guiling , Sykes Megan
Published: March 2003

Rodriguez‐Barbosa JI, Zhao Y, Houser S, Zhao G, Sykes M. Fetal porcine thymus engraftment, survival and CD4 reconstitution in αGal‐KO mice is impaired in the presence of high levels of antibodies against αGal. Xenotransplantation 2003; 10: 24–40. © Blackwell Munksgaard, 2003

Xenospecific T‐cell tolerance can be induced among murine and human T‐cells by porcine thymic grafting. However, anti‐α 1,3‐galactosyltranserase (αGal) (Galα1–3Galβ1–4GlcNAc‐R) natural antibodies (NAbs) pose a major barrier to porcine xenografts in humans. We used αGal knockout (KO) and μ chain KO mice to explore the effect of natural anti‐αGal and other xenoantibodies on porcine thymic engraftment and to examine the potential of thymic tissue to tolerize anti‐αGal antibody‐producing cells.

Thymectomized [adult thymectomy (ATX)] non‐immunized and rabbit red blood cell (RRBC) pre‐transplant immunized αGal‐KO (knockout), wild‐type (WT) and μ chain KO B6 mice were treated with 3Gy total body irradiation (TBI), and T and natural killer (NK) cell depleting monoclonal antibodies (mAbs). These conditioned mice were grafted with fetal porcine thymus and liver (FP THY/LIV) tissue under the kidney capsule. Flow cytometric analysis was performed to follow CD4 reconstitution as a measure of FP THY engraftment and function. Only mice with >10% CD4+ peripheral blood lymphocytes (PBL) were considered successfully engrafted. Enzyme‐linked immunosorbent assay (ELISA) was used to assess the kinetics of immunoglobulin M (IgM) and IgG anti‐αGal antibodies. Anti‐pig antibodies were monitored by flow cytometry (FCM).

FP THY engrafted successfully in most of the immunoglobulin deficient mice (11 out of 12, 92%) and the outcome was similar in WT B6 controls (8 out of 12, 67%). Non‐immunized αGal‐KO mice grafted with FP THY had a similar success rate (7 out of 11) to that observed in non‐immunized αGal‐WT controls (2 out of 4). In contrast, αGal‐KO mice immunized pre‐transplant with RRBC, then grafted with FP THY/LIV, showed a significant reduction in the success of thymic grafting (2 out of 9, 22%) compared with pre‐transplant immunized WT controls (4 out of 7; 57%) and non‐immunized αGal‐KO mice (7 out of 11, 64%). Anti‐Gal and anti‐pig antibody levels were not markedly augmented by porcine thymus grafts in mice with successful thymus grafts.

FP THY engraftment is impaired in the presence of high levels of anti‐αGal xenoantibodies. However, low levels of anti‐αGal antibodies and other mouse anti‐pig NAbs appear not to play a major role in the rejection of FP THY. Although grafting FP THY expressing the αGal epitope did not tolerize B cells producing anti‐αGal antibodies in a T‐cell independent manner, it prevented T‐cell dependent sensitization by inducing T‐cell tolerance to porcine antigens.
Absence of seasonal variation in great tit offspring sex ratios
Authors: Verboven Nanette , Käkelä Minna , Orell Markku
Published: March 2003

When the timing of breeding affects the reproductive value of sons and daughters differently, parents are expected to increase their fitness by changing the offspring sex ratio during the course of the breeding season. Previous studies have shown that in great tits Parus major hatching date has a stronger effect on the fitness of juvenile males than on that of juvenile females. We tested whether this difference was reflected in a seasonal decline in the proportion of sons per breeding attempt. Although offspring sex ratio was more variable than would be expected from a binomial distribution, there was no significant relationship between the proportion of sons and the laying date of the clutch. Moreover, individual females did not adjust the sex ratio of their offspring following an experimental delay of breeding. This study therefore fails to demonstrate adaptive seasonal variation in great tit offspring sex ratios.
Chimpanzee models for human disease and immunobiology
Authors: Muchmore Elaine A.
Published: March 2003

Summary: Chimpanzees have greater than 98% genomic sequence homology with humans but have significantly more favorable reponses to human imunodeficiency virus (HIV)‐1 and hepatitis B virus (HBV) and an apparently low incidence of epithelial malignancy. Although there are few shared major histocompatibility complex (MHC) alleles between human and chimp, there is considerable overlap in binding repertoires for epitopes of HIV‐1 and HBV. This indicates that differences in viral handling may be due to involvement of cells other than T lymphocytes. Similar mechanisms may be involved in host response to dysplastic or malignant cells. In seeking to understand these differences, most attention has been focused on comparing and contrasting well‐characterized steps in immune response. As an additional possibility, alterations in cell–cell interactions dependent upon sialic acid binding proteins known to be involved in immune responses should also be considered. The lack of a particular sialic acid structure (N‐glycolyl neuraminic acid, or Neu5Gc) in humans, due to a gene mutation in an essential synthetic enzyme, has potentially altered the kinetics of cellular responses dependent upon these lectins. The absence of Neu6Gc represents the only known major biochemical difference between humans and chimpanzees.
Regulation of monocyte gene expression by the extracellular matrix and its functional implications
Authors: De Fougerolles Antonin R. , Koteliansky Victor E.
Published: March 2003

Summary: By binding to extracellular matrix (ECM) proteins, integrins integrate signals from outside the cell and transmit them inwards, thereby providing cells with information about location and allowing them to respond to stimuli in a manner appropriate to their environment. This is particularly important for monocytes and macrophages, given their wide distribution throughout the body and the vital role they play in immune and inflammatory responses. Integrin‐mediated interaction of monocytes with ECM is a potent regulator of gene expression and is strongly synergized by the presence of growth factors. This synergy between growth factors and integrins is also apparent in the overlap seen in their signaling pathways. Integrin‐mediated interaction with ECM results in increased expression of numerous inflammatory and immune response genes, revealing an important role for ECM–integrin interaction in affecting monocyte function and thus impacting on the development of pathologies. This is of particular relevance in the context of immune and inflammatory responses, where integrin‐mediated adhesive interactions with the ECM‐rich peripheral tissues are central to the localization of both resident and infiltrating monocytes at inflammatory sites. Here, we will review the functional effects of integrin–ECM interactions on monocytes, with particular attention to the regulation of gene expression by ECM and its functional implications.
The innate immune response to tumors and its role in the induction of T‐cell immunity
Authors: Diefenbach Andreas , Raulet David H.
Published: March 2003

Summary: Recent genetic studies have resurrected the concept that the adaptive and innate immune systems play roles in tumor surveillance. Natural killer (NK) cells recognize many tumor cells but not normal self cells, and they are thought to aid in the elimination of nascent tumors. Two main strategies are employed by NK cells to recognize tumor targets. Many tumor cells down‐regulate class I major histocompatibility complex (MHC) molecules, thus releasing the NK cell from the inhibition provided by class I MHC‐specific inhibitory receptors (‘missing self recognition’). More recently, it has become clear that a stimulatory receptor expressed by NK cells, T cells and macrophages (NKG2D) recognizes ligands (MHC class I chain related [MIC], H6O, retinoic acid early inducible [Rae1] and UL16 binding proteins [ULBP]) that are up‐regulated on tumor cells and virally infected cells but are not expressed well by normal cells. Ectopic expression of these ligands on tumor cells leads to the potent rejection of the tumors in vivo. Importantly, mice that previously rejected the ligand+ tumor cells develop T‐cell immunity to the parental (ligand–) tumor cells. The recognition of induced‐self ligands as a strategy to recognize abnormal self sets a precedent for a new immune recognition strategy of the innate immune system.
Immunity to cancer: attack and escape in T lymphocyte–tumor cell interaction
Authors: Rivoltini Licia , Carrabba Matteo , Huber Veronica , Castelli Chiara , Novellino Luisa , Dalerba Piero , Mortarini Roberta , Arancia Giuseppe , Anichini Andrea , Fais Stefano , Parmiani Giorgio
Published: March 2003

Summary: Tumor cells may express antigens which are recognized in a form of HLA/peptide complexes by T cells. The frequency at which different antigens are seen by T cells of melanoma patients and healthy donors was evaluated by human leukocyte antigen (HLA)/peptide tetramer technology which stains T cells bearing the specific receptor for a given epitope. By this technique, it was found that the majority of metastatic melanoma patients can recognize differentiation antigens (particularly Melan‐A/MART‐1), whereas such a recognition is scanty in the early phase of the disease and in healthy subjects. Despite the presence of melanoma‐specific T cells infiltrating tumor lesions, tumor rejection rarely occurs. Among the different mechanisms of such inefficient antitumor response, this review discusses the possible anti‐T‐cell counterattack mediated by FasL‐positive tumor cells, and shows that FasL is located in the cytoplasm of melanoma cells and is transported in the tumor microenvironment through the release of melanosomes. Additionally, mechanisms of suboptimal T cell activation through tumor cell expression of peptide analogs with antagonist activity are described, together with the possibility of overcoming such anergy induction by the usage of optimized tumor epitopes. Down‐modulation of HLA expression by target tumor cells and its multiple mechanisms is also considered. Finally, we discuss the role of inducible nitric oxide synthases in determining the inhibition of apoptosis in melanoma cells, which can make such tumor cells resistant to the T‐cell attack.
Thymic selection revisited: how essential is it?
Authors: Von Boehmer Harald , Aifantis Iannis , Gounari Fotini , Azogui Orly , Haughn Loralee , Apostolou Irina , Jaeckel Elmar , Grassi Fabio , Klein Ludger
Published: March 2003

Intrathymic T cell development represents one of the best studied paradigms of mammalian development. Lymphoid committed precursors enter the thymus and the Notch1 receptor plays an essential role in committing them to the T cell lineages. The pre‐T cell receptor (TCR), as an autonomous cell signaling receptor, commits cells to the αβ lineage while its rival, the γδTCR, is involved in generating the γδ lineage of T cells. Positive and negative selection of immature αβTCR‐expressing cells are essential mechanisms for generating mature T cells, committing them to the CD4 and CD8 lineages and avoiding autoimmunity. Additional lineages of αβT cells, such as the natural killer T cell lineage and the CD25+ regulatory T cell lineage, are formed when the αβTCR encounters specific ligands in suitable microenvironments. Thus, positive selection and receptor‐instructed lineage commitment represent a hallmark of the thymus. Ectopically expressed organ‐specific antigens contribute to thymic self–nonself discrimination, which represents an essential feature for the evolutionary fitness of mammalian species.
Efficacy of a short‐term ribavirin plus interferon alpha combination therapy followed by interferon alpha alone in previously untreated patients with chronic hepatitis C: a randomized multicenter trial
Authors: Berg Thomas , Hoffmann Robert M. , Teuber Gerlinde , Leifeld Ludger , Lafrenz Michael , Baumgarten Renate , Spengler Ulrich , Zeuzem Stefan , Pape Gerd R. , Hopf Uwe
Published: March 2003

Abstract: Background: Combination therapy with interferon alpha (IFNα) plus ribavirin has been shown to improve the sustained response rate in patients with chronic hepatitis C but there is little information regarding the lengths of time for this therapeutic regimen. In this study we therefore tried to evaluate whether the analysis of different virological parameters could provide new clues with respect to the early determination of the efficacy of this form of combination therapy. Furthermore, we also examined whether short‐term induction combination therapy followed by IFNα alone is more effective than monotherapy in mounting an initial as well as a sustained virological response. Methods: 185 patients with histologically proven chronic hepatitis C (mean age 42 years (range 19–65 years); 110 males, 75 females) were enrolled in the study. The patients were randomly assigned to receive, over the first 12 weeks, either interferon alpha 2a 6 million units (MU) three times weekly plus ribavirin 14 mg/kg per day (n=93) or the same dose of IFNα alone (n=92). Patients with a virological response (serum HCV RNA undetectable) after 12 weeks were subsequently treated with 3 MU IFNα alone thrice weekly for a further 40 weeks. Otherwise, treatment was discontinued. After the end of treatment, patients were followed up for 24 weeks. Results: Patient characteristics at baseline were not significantly different in the two treatment groups. An initial virological response at week 12 was seen in 61 (66%) patients receiving IFNα plus ribavirin and in 44 (48%) being treated with IFNα alone (p=0.015) and this improvement in the response rate was mainly restricted to HCV genotype 1‐infected patients (58% vs. 38%). In contrast, end‐of‐treatment (week 52) and sustained virological response rates were similar in both groups (37% vs. 29% and 26% vs. 17% [p=0.1], respectively). Interestingly, patients with HCV genotype 3, however, clearly benefited from short‐term combination therapy. Thus, sustained virological response rates in these patients significantly increased from 25% (IFNα monotherapy) to 59% (combination therapy) (p=0.05). Conclusions: Short‐term combined therapy for 12 weeks is more effective than the monotherapy with respect to the induction of an initial virological response but this effect applies only to genotype 1‐infected patients. However, there is no significant difference between both therapeutic schedules with regard to the induction of sustained response. Although HCV genotype 3‐infected patients seem to benefit from this short‐term combined therapy, prolonged combined therapy may be necessary in HCV genotype 1‐infected patients.
Macro‐aspartate aminotransferase in a female with antibodies to hepatitis C virus
Authors: Collins John , Ritter Detlef , Bacon Bruce R , Landt Michael , Creer Michael H
Published: March 2003

Abstract: Persistent elevation of aspartate aminotransferase (AST) activity in serum due to the presence of a macroenzyme form of AST (macro‐AST) may lead to diagnostic confusion in many clinical conditions, particularly those associated with chronic liver disease. We describe a case of macro‐AST arising in an adult female with a false‐positive hepatitis C virus (HCV) RNA test result that was not accompanied by other biochemical or histologic evidence of liver disease. The presence of macro‐AST in serum was confirmed utilizing size‐exclusion, high performance liquid chromatography (HPLC) and Protein G‐agarose beads to precipitate immune complexes of AST and immunoglobulin G followed by centrifugation and AST activity measurements in the supernatant. A brief review of the clinical enzymology of AST and methods used to quantify serum macro‐AST activity is provided.
Portal vein arterialisation as a technical option in liver transplantation: impact on function, regeneration, and morphology of the liver following hemihepatectomy in pigs
Authors: Ott Rudolf , Schuppan Detlef , Tannapfel Andrea , Wittekind Christian , Erhardt Wolf , Henke Julia , Kilic Nu , Köckerling Ferdinand , Reck Thomas , Hohenberger Werner , Müller Volker
Published: March 2003

Abstract: Background: Arterialisation of the portal vein has been propagated as a technical variant in liver transplantation. However, the consequences of this unphysiological vascular supply are insufficiently known. Methods: Twenty‐seven healthy pigs were subjected to a left hemihepatectomy and divided into three groups. The first group received complete arterialisation of the portal vein (PVA). In the second group hepatic artery blood flow was also interrupted by dividing the artery (PVA/DHA). Nine animals served as controls (Group C). Results: Early mortality in the PVA/DHA group (6/9) was significantly increased in comparison with the PVA (2/9) and control (2/9) groups (P < 0.05). In the surviving animals, arterialisation (PVA and PVA/DHA) led to significantly faster hepatic regeneration in comparison with control animals, with comparable liver function and with liver size increasing to 278% and 293% vs 134% (P= 0.002) after 3 weeks, in liver … weeks. This was accompanied by enhanced hepatic expression of the proliferation markers MIB‐1(22.4% and 16.7% vs 5.9%, P = 0.002) and PCNA(86% and 68% vs 66%, P = 0.002) one week postoperation. At the same time, the number of apoptotic hepatocytes increased from 1.6% to 2.5% and 2.3% (P= 0.002). No significant difference was found in the collagen content of the liver after 3 weeks. Conclusions: Arterialisation of the portal vein promotes early and enhanced hepatic regeneration without impairing liver function. This technique may therefore be useful in split‐graft liver transplantation, where this aspect would be of particular importance.
Previous hepatitis B virus infection is associated with worse disease stage and occult hepatitis B virus infection has low prevalence and pathogenicity in hepatitis C virus‐positive patients
Authors: Giannini Edoardo , Ceppa Paola , Botta Federica , Fasoli Alberto , Romagnoli Paola , Ansaldi Filippo , Durando Paolo , Risso Domenico , Lantieri Pasquale B. , Icardi Gian C. , Testa Roberto
Published: March 2003

Abstract: Background: Anti‐hepatitis C virus (anti‐HCV) patients with chronic liver disease (CLD) frequently show markers of previous hepatitis B virus (HBV) infection. Moreover, they may carry occult HBV infection. These features might influence clinical and biochemical features as well as stage of disease. Aim: To assess the prevalence and clinical associations of previous (positivity for anti‐HBs and/or anti‐HBc antibodies) and occult HBV infection (positivity for HBV‐DNA by nested‐PCR) in the serum of anti‐HCV‐positive, HCV‐RNA‐positive, HBsAg‐negative patients with various degrees of CLD seen at a tertiary referral centre. Patients: A total of 119 patients fulfilled the inclusion criteria (84 chronic hepatitis and 35 liver cirrhosis). Results: Forty‐eight patients (40.3%) showed markers of previous HBV infection. This feature was more frequent (P = 0.02) among cirrhotics (57%) as compared to chronic hepatitis patients (33%). Chronic hepatitis patients positive for markers of previous HBV infection had worse histology as compared to negative ones (grading: 6.4 ± 2.7 versus 4.6 ± 3.0, P = 0.004; staging: 1.6 ± 1.2 versus 1.0 ± 1.0, P = 0.01). Eight patients were positive for HBV‐DNA in serum (6.7%). No difference in the presence of occult HBV infection was seen between various degrees of liver disease (7.1% of chronic hepatitis, 5.7% of cirrhosis) and among patients who were positive (10.4%) or negative (4.2%) for markers of previous HBV infection. No significant biochemical, virological, or histological difference was observed between age, age at infection, duration of infection, marker patterns of previous HBV infection‐matched HBV‐DNA‐positive and negative chronic hepatitis patients. Conclusions: Our findings suggest that previous HBV infection among anti‐HCV patients is associated with worse disease stage. In these patients, the prevalence of occult HBV infection is low and there is no difference in distribution among patients with or without markers of previous HBV infection. Furthermore, it does not seem to be associated with disease stage. Lastly, at least among patients with chronic hepatitis, it does not seem to affect the severity of disease.
Spontaneous terminal ileitis resembling Crohn disease in captive tamarins
Authors: Gozalo A. , Dagle G.E. , Montoya E. , Weller R.E.
Published: March 2003

Five tamarins (four Saguinus mystax and one S. labiatus) died with wasting syndrome characterized by chronic diarrhea at the Center for Reproduction and Conservation of Non‐Human Primates in Iquitos, Peru. At necropsy, the terminal ileum of all affected tamarins was found to be markedly thickened. Histologically, the terminal ileal mucosa was completely ulcerated, and effaced by debris and mononuclear inflammatory cells. The submucosa and serosa were thickened by fibroplasia, mononuclear cell infiltrates and variable edema. No infectious agent was observed. The lesions were similar to those described previously for Crohn disease. This is to our knowledge the first report of terminal ileitis resembling Crohn disease in non‐human primates.
Spontaneous pancreatic islet amyloidosis in 40 baboons
Authors: Hubbard G.B. , Steele K.E. , Davis K.J. , Leland M.M.
Published: March 2003

Spontaneous amyloidosis occurs in many nonhuman primate species but remains difficult to diagnose and treat. Nonhuman primates continue to offer promise as animal models in which to study amyloidosis in humans. Amyloidosis was not diagnosed clinically but was found histologically in four male and 36 female baboons. The baboons averaged 18 years of age at death (range, 7–28 years). Clinical signs, if present, were hyperglycemia and cachexia. Blood glucose values were elevated in 12 of 30 baboons with available clinical pathology data. Four baboons had been clinically diagnosed as diabetic and three were treated with insulin. Amyloid was found in the islets of Langerhans of the pancreas in 40 baboons; 35 baboons had amyloid only in the islets of Langerhans. Amyloid was found in nonislet tissue of baboons as follows: five, nonislet pancreas; four, intestine and adrenal; three, kidney; two, prostate and spleen; and one each, lymph node, liver, gall bladder, stomach, tongue, urinary bladder, and salivary gland. Sections of paraffin‐embedded tissues were evaluated for amyloid with hematoxylin and eosin (HE) and congo red (CR) staining, and using immunohistochemistry for human islet amyloid polypeptide (IAPP), calcitonin gene‐related peptide (CGRP), glucagon, pancreatic polypeptide (PP), somatostatin (SS), and porcine insulin. Islet amyloid was positive with HE in 40 baboons, with CR in 39 baboons, and with IAPP and CGRP in 35 baboons. IAPP and CGRP only stained islet amyloid. PP, SS, glucagon, and porcine insulin did not stain amyloid. Islet amyloidosis in the baboon appears to be difficult to diagnose clinically, age‐related, and similar to islet amyloidosis in other species. The baboon may be a good model for the study of islet amyloidosis in humans.
Proliferative response of peripheral blood lymphocytes to mitogens in the owl monkey Aotus nancymae
Authors: Pinzón‐Charry Alberto , Vernot Jean Paul , Rodríguez Raul , Patarroyo Manuel Elkin
Published: March 2003

Abstract: The new world primate Aotus sp. has been recommended by the World Health Organization as a model for evaluation of malaria vaccine candidates, given its susceptibility to experimental infection with the human malaria parasites Plasmodium falciparum and P. vivax. The present study examined the in vitro proliferative response of peripheral blood mononuclear cells (PBMCs) isolated from Aotus monkeys, utilizing a wide range of mitogens. Results presented herein demonstrate that the in vitro proliferative response of PBMCs from the Aotus sp. is quite variable from monkey to monkey for each of the mitogens assessed. PBMCs from the Aotus monkey exhibited a delayed kinetic proliferative response and, particularly, a different sensitivity to proliferation in response to various concentrations of Phytohemagglutinin‐P and favin lectins, the phorbol ester Phorbol myristate acetate and the calcium ionophore ionomycin. Altogether, our findings are consistent with the conclusion that the in vitro proliferative response of PBMCs from the Aotus differ in their activation requirements compared with PBMCs from humans.
Design and implementation of slag practices for reduction in refractory consumption at BHP steelmaking centres
Authors: Lee Mark , Jahanshahi Sharif
Published: March 2003

BHP Steel produces about 8 million tpa of steel for the local and overseas markets. The costs associated with refractory materials are considerable and thus strategies have been developed to reduce the refractory wear in steelmaking operations. The approaches developed take into account some of the key fundamental factors influencing the metallurgical performance of the process and the rate of chemical attack of refractories by molten slags. Thermodynamic models have been used for analysis of plant data and design/tuning of suitable practices to prolong the refractory life via in‐situ coating of refractories with solid phases with high resistance to slag attack. Examples of the results obtained from implementation of such practices are presented.
Estimating predation rates in experimental systems: scale‐dependent effects of aggregative behaviour
Authors: Bergström Ulf , Englund Göran
Published: March 2003

We studied the effect of arena size on estimates of prey mortality rate in predation experiments. In a laboratory experiment involving two of the dominating benthic species in the northern Baltic Sea, the predacious isopodSaduria entomon, and its main prey, the amphipodMonoporeia affinis, the prey mortality rate increased with container radius. The densities of both predator and prey close to the wall increased with container size. We hypothesised that this scale‐dependent coaggregation of predator and prey caused the mortality rates to increase with arena size. We tested the hypothesis with the help of a simple model, by calculating the expected number of prey eaten in containers of different size from experimental data on the distributions of predator and prey within the arenas. A significant relationship between expected and observed numbers eaten supported our hypothesis. As the aggregative response was most pronounced in large arenas, this leads to the counterintuitive conclusion that large containers produced more biased estimates of morality rates than small containers.  To further study the effects of coaggregation we explored a general simulation model where both predator and prey preferred the habitat close to the arena wall. The model predicted a humpshaped relationship between encounter rate and arena size. This suggests that when predators and prey show a scale‐dependent tendency to aggregate along arena walls, the most accurate estimates of predation rates may be obtained with very small or very large arenas.
The costs of mounting an immune response are reflected in the reproductive fitness of the mosquito Anopheles gambiae
Authors: Ahmed A. M. , Baggott S. L. , Maingon R. , Hurd H.
Published: March 2003

We have used Anopheles gambiae, a major vector of malaria in Africa, to test the hypothesis that the operation of a surveillance or immune system against microorganisms and parasites can be costly to the reproductive success of the host. Blood‐fed mosquitoes were challenged with an immune elicitor, lipopolysaccharide (LPS), and their resultant antimicrobial activity, accumulation of yolk protein in the ovary and egg production was monitored. Humoral activity against the Gram‐positive bacterium Micrococcus luteus was induced by LPS injection in a dose‐responsive manner. LPS treatment also caused a concomitant significant reduction in the accumulation of protein in ovaries 24 h after injection and in the production of eggs during the same gonotrophic cycle. Unlike immune stimulation, reduction in reproductive fitness was not dose responsive. Oral administration of LPS also significantly reduced ovarian protein content although we could not detect the presence of anti‐M. luteus activity in the gut tissue by using an inhibition zone assay. These findings indicate that immune stimulation imposed reproductive fitness costs on mosquitoes.
Plant responses to fertilization and exclusion of grazers on an arctic tundra heath
Authors: Grellmann Doris
Published: March 2003

This study investigated the impacts of fertilization and grazing by Norwegian lemmings (Lemmus lemmus), grey‐sided voles (Clethrionomys rufocanus), and reindeer (Rangifer tarandus) on a diverse tundra plant community dominated by deciduous shrubs. Four out of eight study areas, having a size of 2500 m2 each, were fertilized with a N‐P‐K fertilizer and four areas served as unfertilized controls. Two types of exclosures were used within each study area, one to exclude solely reindeer, and one to exclude both rodents and reindeer. Open, grazed plots served as controls. During 5 years following the fertilization event the changes in vegetation inside and outside the exclosures were monitored using a point frequency method. The densities of rodents on the fertilized and unfertilized areas were investigated by live trapping and by counting nests of overwintering individuals. Reindeer do not graze on the study area during the growing season but migrate through this area in autumn and spring. Fertilization increased the abundance of vascular plants while grazing by reindeer and rodents decreased the abundance of vascular plants significantly on both fertilized and unfertilized areas. Rodents preferred clearly the fertilized areas during winter, decreasing the abundance of Vaccinium myrtillus and Vaccinium vitis‐idaea, while very little grazing occurred during summer. Graminoids showed the strongest positive response to fertilization and dominated the plant community on ungrazed plots, while winter grazing by both reindeer and rodents significantly decreased the abundance of graminoids. Deciduous shrubs (Betula nana, Vaccinium myrtillus) increased slightly but significantly due to fertilization and evergreen dwarf shrubs showed no response to fertilization. However, the use of functional growth forms for predicting the responses of nutrient enrichment and grazing must be questioned, as responses to fertilization as well as preferences by herbivores were shown to be species‐specific rather than uniform within functional groups based on plant growth forms.
How perennial are perennial plants?
Authors: Ehrlén Johan , Lehtilä Kari
Published: March 2003

Trade‐offs involving life span are important in the molding of plant life histories. However, the empirical examination of such patterns has so far been limited by the fact that information on life span is mainly available in terms of discrete categories; annuals, semelparous perennials and iteroparous perennials. We used transition matrix models to project continuous estimates of conditional life spans from published information on size‐ or stage‐structured demography for 71 perennial plant species. The projected life span ranged from 4.3 to 988.6 years and more than half of the species had a life span of more than 35 years. Woody plants had on average a projected life span more than four times as long as non‐woody plants. Life spans were higher in forests than in open habitats and individuals of non‐clonal species tended to have a longer life span than ramets of clonal species. Self‐incompatible plants on average lived longer than self‐compatible plants. There were no clear relations between life span and geographical region, dispersal syndrome, pollination mode, seed size or the presence of a seed bank. We conclude that accurate estimates of life span are central to understand how longevity is correlated to other traits within the group of perennial plants.
The additive partitioning of species diversity: recent revival of an old idea
Authors: Veech Joseph A. , Summerville Keith S. , Crist Thomas O. , Gering Jon C.
Published: March 2003

Ecologists have traditionally viewed the total species diversity within a set of communities as the product of the average diversity within a community (alpha) and the diversity among the communities (beta). This multiplicative concept of species diversity contrasts with the lesser known idea that α‐ and β‐diversities sum to give the total diversity. This additive partitioning of species diversity is nearly as old as the multiplicative concept, yet ecologists are just now beginning to use additive partitioning to examine patterns of species diversity. In this review we discuss why additive partitioning remained “hidden” until just a few years ago. The rediscovery of additive partitioning has expanded the way in which ecologists define and measure β‐diversity. Beta diversity is no longer relegated to describing change only along an environmental gradient. Through additive partitioning, β‐diversity is explicitly an average amount of diversity just as is α‐diversity. We believe that the additive partitioning of diversity into α and β components will continue to become more widely used because it allows for a direct comparison of α‐ and β‐diversities. It also has particular relevance for testing ecological theory concerned with the determinants of species diversity at multiple spatial scales and potential applications in conservation biology.
The distribution of Melanoplus femurrubrum: fear and freezing in Connecticut
Authors: Beckerman Andrew P.
Published: March 2003

A central challenge for those studying organism distributions is to identify the relevant scale at which a distribution is established and the relevant mechanism driving the maintenance of the pattern. Melanoplus femurrubrum grasshoppers in NE Connecticut are missing from grass dominated fields. I examined two hypotheses about why the grasshopper is missing from these types of fields in this region. The first hypothesis was that behavioural responses to predation and competition prevent establishment by limiting above ground stages of the grasshopper. The second hypothesis was that soil temperature and grass habitat characteristics influence oviposition behaviour and limit egg development. Testing among these different hypotheses (trophic vs abiotic), data from experiments and field observations indicated that while the within field distribution of M. femurrubrum can be sensitive to the effects of trophic interactions during the above ground phase of the life‐cycle, the among field distribution is limited by female oviposition choice, limited heating degree‐days for egg development, and poor resource conditions for the first instar grasshoppers. These results highlight the need to examine behaviour and community interactions across habitats and life stages in studies of distribution patterns.
Rethinking the role of many plant phenolics – protection from photodamage not herbivores?
Authors: Close Dugald C. , McArthur Clare
Published: March 2003

Phenolics have been considered classic defence compounds for protecting plants from herbivores, ever since plant secondary metabolites were suggested to have evolved for that reason. The resource availability and carbon‐nutrient balance hypotheses proposed that variation in phenolic levels between and within plant species reflects environmental availability of nutrients and light, and represents a trade‐off in allocation by plants to growth and defence against herbivores. In contrast to these concepts, we suggest that (1) the main role of many plant phenolics may be to protect leaves from photodamage, not herbivores; (2) they can achieve this by acting as antioxidants; and (3) their levels may vary with environmental conditions in order to counteract this potential photodamage. We therefore suggest that patterns in phenolic levels, often used to support the concept of trade‐off between growth and herbivore defence in relation to resource availability, may actually reflect different risks of photodamage. We suggest that the level of many phenolics is low under some environmental conditions, not because resources to produce them are limited, but simply because the risk of photodamage is low and they are not required. If our photodamage hypothesis is correct, a reassessment of the ecological and evolutionary role of many phenolics in plant defence theory is required.