bluuebunny/crossref_metadata_2025 huggingface dataset:
Isolation of photorespiratory mutants from Lotus japonicus deficient in glutamine synthetase
Authors: Orea Alicia , Pajuelo Purificación , Pajuelo Eloísa , Quidiello Concepción , Romero José M. , Márquez Antonio J.
Published: March 2003

A mutagenesis programme using ethyl methanesulphonate (EMS) was carried out on Lotus japonicus (Regel) Larsen cv. Gifu in order to isolate photorespiratory mutants in this model legume. These mutants were able to grow in a CO2‐enriched atmosphere [0.7% (v/v) CO2] but showed stress symptoms when transferred to air. Among them, three mutants displayed low levels of glutamine synthetase (GS; EC 6.3.1.2) activity in leaves. The mutants accumulated ammonium in leaves upon transfer from 0.7% (v/v) CO2 to air. F1 plants of back crosses to wild type were viable in air and F2 populations segregated 3 : 1 (viable in air : air‐sensitive) indicative of a single Mendelian recessive trait. Complementation tests showed that the three mutants obtained were allelic. Chromatography on DEAE‐Sephacel used to separate the cytosolic and plastidic GS isoenzymes together with immunological data showed that: (1) mutants were specifically affected in the plastidic GS isoform, and (2) in L. japonicus the plastidic GS isoform eluted at lower ionic strength than the cytosolic isoform, contrary to what happens in most plants. The plastidic GS isoform present in roots of wild type L. japonicus was also absent in roots of the mutants, indicating that this plastidic isoform from roots was encoded by the same gene than the GS isoform expressed in leaf tissue. Viability of mutant plants in high‐CO2 conditions indicates that plastidic GS is not essentially required for primary ammonium assimilation. Nevertheless, mutant plants did not grow as well as wild type plants in high‐CO2 conditions.
Role of phosphoenolpyruvate carboxylase in anaplerosis in the green microalga Dunaliella salina cultured under different nitrogen regimes
Authors: Norici Alessandra , Dalsass Alessia , Giordano Mario
Published: March 2003

Anaplerosis plays a very important role in providing C for N assimilation. In green algae and higher plants, phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) is the main anaplerotic carboxylase. On this basis we hypothesize that N availability affects PEPC expression. In order to test this hypothesis, the model organism Dunaliella salina was cultured under a variety of N growth regimes. Our results show that the level of PEC activity was unaffected by the N form in which N was supplied to the cells, when N concentration was low (0.5–0.01 mM). When cells were adapted to growth at 5 mM N, however, PEPC activity on a per cell basis was substantially higher in NH4+‐adapted cells as compared to their NO3–‐adapted counterparts; however, the same difference was not observed on a protein basis. This notwithstanding, even at low N, PEPC of cells cultured in the presence of either NH4+ or NO3– appeared to differ in their molecular masses. These results suggest that cells adapted to different N‐form express distinct PEPC isoforms. In addition to this, we observed that, in algae adapted to high (5 mM) NH4+ concentration, a PEPC isoform was induced that differed from the isoforms observed in algae adapted to lower concentrations of the same N‐source. These findings lead us to conclude that the expression of PEPC isoforms in D. salina responds to the variation in the C‐skeleton demand deriving from changes in the chemical form and availability of N.
A comparative study on the aluminium‐ and copper‐induced organic acid exudation from wheat roots
Authors: Nian Hai , Yang Zheng Ming , Ahn Sung Ju , Cheng Zhi Jun , Matsumoto Hideaki
Published: March 2003

It is well established that aluminium (Al) and some heavy metals can elicit organic acid exudation from a range of species. In the present research we found that copper (Cu) can also induce organic acid exudation from the roots of wheat, rye, triticale, maize and soybean. Using intact wheat plants, we made a comparative study of Al‐ and Cu‐ induced organic acid exudation. In 5‐day‐old wheat seedlings, severe Cu stress (40 µM CuCl2) mainly induced the exudation of malate and citrate, and Al‐tolerant genotypes could release significantly greater amounts of malate than Al‐sensitive genotypes. The time course of the exudation of malate and citrate from the roots of 5‐day‐old seedlings of wheat (cv. Atlas) in 200 µM AlCl3 was similar to that in 40 µM CuCl2. In older wheat plants (15‐day‐old), moderate Cu stress (12 µM CuCl2) induced the exudation of large amounts of citrate and addition of Al or La sharply reduced Cu‐induced citrate exudation, while Cu or La did not affect Al‐induced malate efflux. When half of the root system of Atlas wheat was immersed in Al‐ or Cu‐containing solution and the remaining half in Al‐ or Cu‐free solution, organic acids were only exuded into the solution containing Al or Cu. This suggests that no long distance signal transport is involved in organic acid exudation induced by Al or Cu, and that direct contact of Al or Cu with plant roots is a prerequisite for the induction of organic acid exudation. The anion‐channel inhibitor niflumic acid (NIF) significantly stimulated the exudation of both citrate and malate from 5‐day‐old wheat seedlings under severe Al or Cu stress. Our results suggest that Cu‐induced organic acid efflux may be a common response, which may play a role in alleviating Cu toxicity in plants.
Interaction between exogenous glycine betaine and the photorespiratory pathway in canola leaf discs
Authors: Sulpice Ronan , Gibon Yves , Cornic Gabriel , Larher François Robert
Published: March 2003

The uptake and accumulation of exogenously supplied glycine betaine (GB) by canola (which never accumulates GB in response to stress) leaf discs has been found to induce damage to some of their structural and functional components. As a consequence some free amino acids were accumulated, particularly glutamine and glycine. Similar results were obtained with leaf discs of Arabidopsis thaliana i.e. another cruciferous plant that does not naturally produce significant amounts of GB. In contrast no changes in glutamine and glycine contents were observed in response to the GB treatment in leaf discs of spinach, a natural producer of GB. The change in glutamine content might be related to the senescing effects caused by the GB treatment. Glycine accumulation in response to GB has been more thoroughly studied with canola leaf discs. It only occurred under light conditions and was suppressed under non‐photorespiratory conditions. The accumulation of glycine in canola leaf discs in response to GB was either restricted when GB was added in the presence of aminooxyacetate (an inhibitor of transaminases) or enhanced when added in the presence of aminoacetonitrile (an inhibitor of glycine decarboxylation by mitochondria). Both compounds are known to block the glycolate pathway. Glycine accumulation was not found in leaf discs of Zea mays treated in the light in the presence of GB. These results suggest that the absorbed GB could exert destabilizing effects on the photorespiration of the C3 cruciferous plants canola and Arabidopsis via competitive effects between GB and glycine at the mitochondrial step of the glycolate pathway. The mechanism of the GB effect remains to be elucidated as well as that of its apparent compatibility in spinach, the well known natural producer of GB.
Inhibition of growth and development of root border cells in wheat by Al
Authors: Zhu Mu‐yuan , Ahn Sung‐ju , Matsumoto Hideaki
Published: March 2003

The production and development of border cells vary with genotype, and they are released in wheat at an earlier stage of root development than other species studied so far. No significant difference was observed in the maximum number of border cells between Al‐tolerant (Atlas 66) and Al‐sensitive (Scout 66) cultivars in the absence of Al treatment. Al seriously inhibited the production and release of border cells, resulting in clumping of border cells in Scout 66, but less clustering in Atlas 66. The number of border cells released from roots treated with Al is significantly less than that from roots grown without Al treatment. Al treatment induced the death of detached border cells in vitro and they were killed by a 20‐h treatment with 25 µm Al. No significant difference in survival percentage of detached border cells was observed between Atlas 66 and Scout 66, regardless of the presence or absence of Al. The removal of border cells from root tips of both Atlas 66 and Scout 66 enhanced the Al‐induced inhibition of root elongation concomitant with increased Al accumulation in the root. These results suggest that border cells adhered to the root tips play a potential role in the protection of root from Al injury in wheat.
Current antiviral strategies for controlling cytomegalovirus in hematopoietic stem cell transplant recipients: prevention and therapy
Authors: Boeckh M.
Published: March 2003

Cytomegalovirus (CMV) remains a cause of significant morbidity and mortality after hematopoietic stem cell transplantation (HSCT). Ganciclovir prophylaxis, or preemptive treatment based on detection of antigenemia or CMV DNA by PCR, effectively prevents CMV disease during the first 100 days after transplant in allograft recipients. In recipients of T‐cell depleted transplant or if severe acute graft‐versus‐host disease is present, ganciclovir prophylaxis or preemptive treatment should be started with an induction course of ganciclovir (5 mg/kg BID) and given at least 5 days per week and continued until day 100 after transplant. Although prevention of CMV disease before day 100 is highly effective, there is a continued risk of late‐onset CMV disease after day 100. In CMV‐seropositive recipients, the incidence of late CMV disease may be as high as 17%. Strategies to prevent late CMV infection and disease are needed. In seronegative recipients, seronegative or leukocyte‐reduced blood products are effective in preventing acquisition of CMV through blood products. Controversy exists about the optimal strategy of preventing CMV disease in seropositive autologous HSCT recipients. The outcome of CMV pneumonia remains poor despite treatment with ganciclovir in combination with CMV hyperimmune globulin or intravenous immunoglobulin. Owing to continued clinical significance of CMV in the HSCT setting, new and more effective anti‐CMV drugs with improved pharmacokinetic properties are urgently needed.
Intrathymic inoculation of donor antigen: an ineffective strategy for prolonging xenograft survival
Authors: Tran Hanh M. , Patel Anita , Allen R. D. M. , O’Connell Philip J.
Published: March 2003

The aim of this study was to determine whether intrathymic inoculation of the recipient with donor antigen and short‐term depletion of peripheral lymphocytes would lead to donor‐specific unresponsiveness to rat pancreatic islet xenografts. The results were compared directly with an allograft model to determine whether there were substantial differences in the mechanisms of graft prolongation between allografts and xenografts using an identical conditioning regimen. Streptozotocin‐induced diabetic C57B6 mice were injected with up to 0.3 ml of rat anti‐mouse lymphocyte serum (ALS) 1 day before intrathymic injection of donor splenocytes. DA rat islet xenografts or Balb/c mouse islet allografts were transplanted 3 days later. ALS depleted CD3+ and CD4+ peripheral blood T lymphocytes to less than 5% of values in control mice by 24 h. Median islet xenograft survival (MGS) was 9 days in untreated mice, 28 days in mice receiving 0.2 ml of ALS and 32 days in mice receiving 0.3 ml of ALS alone. Intrathymic injection of 5 × 106 DA splenocytes plus 0.2 ml of ALS did not improve islet xenograft survival beyond 28 days. Increasing the intrathymic inoculum to 107 DA splenocytes with or without a higher dose of ALS (0.3 ml) did not increase MGS beyond 26 days, although 2 out of 18 animals survived beyond 100 days. These long‐term surviving mice rejected a second DA rat islet graft in less than 22 days, indicating that tolerance was not achieved. To confirm the efficacy of this treatment regimen in allotransplantation, diabetic C57B6 mice received 107 Balb/c splenocytes intrathymically and 0.3 ml of ALS. A Balb/c islet allograft was performed 3 days later. Allograft survival was similar to that of rat islet xenografts with 40% (4 out of 10) of grafts surviving beyond 100 days. In contrast to the xenograft recipients, a second Balb/c islet allograft survived indefinitely, indicating that tolerance was achieved. Histology of the long‐surviving allografts showed intact islets with a sparse cellular infiltrate, whereas the long‐surviving xenografts (> 100 days) showed a large cellular infiltrate and significant islet destruction. To investigate further the role of the thymus, adult thymectomized C57B6 mice were treated with 0.3 ml of ALS and received a DA rat islet xenograft. The median graft survival was 52 days and no graft survived beyond 80 days, suggesting that peripheral xenoreactive T cells remained after ALS treatment and greater T‐cell depletion was necessary to obtain permanent engraftment. These results show that peripheral xenoreactive T cells which remain after profound T‐cell depletion are capable of rejecting an islet xenograft despite intrathymic inoculation of donor antigen. The T‐cell‐mediated xenograft response appears to be stronger and more difficult to suppress than the allograft response using this strategy.
Differential galactose α(1,3) galactose expression by porcine cardiac vascular endothelium
Authors: Chen Raymond H. , Mitchell Richard N. , Kadner Alexander , Adams David H.
Published: March 2003

Galactose α(1,3) galactose (Gal) is the terminal carbohydrate moiety recognized by xenoreactive natural antibodies during hyperacute rejection (HAR). Binding of these antibodies in HAR triggers rapid microvascular thrombosis. We examined the distribution of Gal on the endothelium of porcine hearts before and after heterotopic xenotransplantation into baboons. We found that Gal is strongly expressed on the endothelium of porcine capillaries with less expression on the endothelium of larger vessels. The distribution of Gal staining remains unchanged after xenotransplantation and correlates with the intensity of IgM and membrane attack complex (MAC) deposition. Thus, the Gal epitope is differentially expressed in the pig vasculature, which affects the pattern of xenoreactive antibody and MAC deposition and directs the distribution of vascular thrombosis.
Heterotopic cardiac xenotransplantation: fish‐to‐rat
Authors: Yu Weiming , Wright Jr James R.
Published: March 2003

The purpose of this study was to determine whether a vascularized organ transplanted from a teleost fish to a rodent would be hyperacutely rejected. Previous reports describing the results of discordant xenotransplantation are almost exclusively across orders within the class Mammalia. We chose a species combination that crosses many phylogenetic barriers (i.e. species, genus, family, order, and class) as well as several hundred million years on an evolutionary timescale. Because no published methodology existed, we developed a microvascular surgical method for fish (tilapia)‐to‐rat heterotopic cardiac xenotransplantation. To minimize the blood pressure to which the graft would be exposed, the tilapia heart was placed on the venous side of the rat circulation between the left kidney and the inferior vena cava by end‐to‐side anastomoses of the donor aorta to the recipient inferior vena cava and by end‐to‐end anastomosis of the donor sinus venosus to the recipient left renal vein. Tilapia hearts were rejected hyperacutely, based on both routine histopathological examination and immunofluorescent staining for immunoglobulin and complement, but rejection required hours rather than minutes.
Different responses of human anti‐HLA and anti‐αgal antibody to long‐term intravenous immunoglobulin therapy
Authors: Bühler L. , Pidwell D. , Dowling R.D. , Newman D. , Awwad M. , Cooper D.K.C.
Published: March 2003

Concentrated human immunoglobulin (IVIG) has been administered intravenously in the treatment of autoimmune disorders and to reduce anti‐HLA antibodies in highly sensitized patients awaiting organ transplantation. It has also been shown, in experimental animals, to prevent the hyperacute rejection of discordant xenografts, possibly by anticomplement activity. The aim of the present study was to assess the effect of IVIG therapy on both acquired anti‐HLA antibodies and natural antigalactose α1–3 galactose (αGal) antibodies in five patients awaiting heart transplantation. Five patients placed on mechanical circulatory support who had developed high HLA panel‐reactive antibodies (PRA) or in whom the percentage of PRA was increasing rapidly were treated weekly with 500 mg/kg IVIG, which contained 1% of anti‐αGal IgG. Levels of PRA, anti‐αGal IgG and IgM, and serum cytotoxicity to pig cells were measured before, during, and after therapy. PRA percentages in the five patients were initially 85%, 53%, 23%, 19% and 19% (mean 39%). Mean PRA fell by 66% after 3 months of therapy (to a mean PRA of 14%), and by 96% after 6 months therapy (to a mean PRA of 2%). Anti‐αGal antibody levels and serum cytotoxicity to pig aortic endothelial cells did not change significantly. These results confirm the effectiveness of IVIG therapy in reducing PRA in HLA highly sensitized patients. It is likely that IVIG does not contain the relevant anti‐HLA antibody, resulting in an accelerated catabolism of native alloantibodies. However, as IVIG contains a normal level of anti‐αGal IgG, catabolism of anti‐αGal IgG is not modified, as it is being continuously replaced. To achieve a decrease in the anti‐αGal IgG level it would be necessary to use IVIG depleted of this antibody.
The target antigens of naturally occurring human anti‐β‐galactose IgG are cryptic on porcine aortic endothelial cells
Authors: Lucq Julia , Tixier Denis , Guinault Anne Marie , Greffard Anne , Loisance Daniel , Pilatte Yannick
Published: March 2003

Abstract: The identification of the xeno‐antigens/xeno‐antibodies combinations involved in pig‐to‐human xenograft rejection is an essential step for understanding this process and for the development of procedures to prevent it. Although it is widely accepted that the terminal disaccharide Galα1,3Gal‐R is by far the major epitope recognized by human natural antibodies reactive with pig tissues, there is also evidence that other carbohydrates epitopes might be important in xenograft rejection.

In an attempt to further improve our knowledge of the repertoire of human natural antibodies with anti‐pig specificity we sought to determine whether naturally occurring human anti‐β‐galactose IgG could interact with porcine aortic endothelial cells (PAEC). Histochemical analysis of porcine aorta sections revealed that the carbohydrate structures recognized by the anti‐β‐galalactose IgG are present on endothelial cells but in a cryptic form that can be unmasked by sialidase treatment. These structures were also found to be cryptic in cultured PAEC. In addition we demonstrated that PAEC may adsorb fetal calf serum (FCS) glycoproteins when cultured in FCS‐supplemented medium, a process susceptible to generating artifactual observations in carbohydrate antigens analysis.

In conclusion, despite their abundance, human anti‐β‐galactose IgG do not represent a primary concern in pig‐to‐human xenotransplantation as the carbohydrate structures to which they bind are normally masked by sialic acid residues on porcine endothelial cells. However, whether these cryptic epitopes might be exposed on endothelial cells from genetically engineered animals should be further investigated because, if so, additional approaches will be needed to suppress their interaction with human anti‐β‐galactose IgG.
Delayed type hypersensitivity‐associated cytokines in islet xenotransplantation: limited efficacy of interleukin‐2‐ and tumor necrosis factor‐α‐blockade in interferon‐γ receptor‐deficient mice
Authors: Benda Birgitta , Lycke Nils , Holstad Maria , Korsgren Olle
Published: March 2003

Abstract: To investigate the role of interferon (IFN)‐γ and tumor necrosis factor (TNF)‐α and their potential to replace each other in the process of fetal porcine islet‐like cell cluster (ICC) xenograft rejection, mice with a targeted disruption of the IFN‐γ receptor gene and wild‐type controls were transplanted with fetal porcine ICCs under the kidney capsule and given post‐transplant treatment with the TNF‐α‐inhibiting agent MDL 201,449A. Some of the MDL 201,449A‐treated IFN‐γ receptor‐deficient mice received additional treatment with cyclosporinee (CsA). Evaluation of the xenografts was performed 7 days after transplantation (all groups), and in IFN‐γ receptor‐deficient mice treated with MDL 201 449 A, also 10 and 13 days after transplantation. On day 7 after transplantation, a few CD3+ cells were seen accumulated peripherally in the ICC xenograft. Moderate to abundant numbers of F4/80+ and Mac‐1+ cells surrounded a few remaining ICCs present within the xenograft. Histochemical visualization of cyanide‐resistant endogenous peroxidase activity for detection of eosinophils demonstrated only small numbers of eosinophils present within the xenograft by day 7 after transplantation. An increased amount of eosinophilic granulocytes was not found until day 10 after transplantation, i.e. at a time when ICC xenograft rejection has already been completed. However, two out of six IFN‐γ receptor‐deficient mice given post‐transplant treatment with CsA and MDL 201,449A exhibited intact ICC xenografts with ICCs arranged in chords and duct‐like structures on day 7 after transplantation. Taken together, findings in this study indicate that, in the pig‐to‐mouse model, IFN‐γ, TNF‐α, and interleukin‐2 seem to be of importance to fetal porcine ICC xenograft rejection. Nevertheless, in a majority of animals, other cytokines eventually substitute for the lack of IFN‐γ, TNF‐α and interleukin‐2.
Inducible nitric oxide synthetase is expressed in adult but not fetal pig pancreatic islets
Authors: Feng Ximin , Yi Shounan , Hawthorne Wayne J. , Patel Anita T. , Walters Stacey N. , O'Connell Philip J.
Published: March 2003

Abstract: Cytokine‐induced expression of inducible nitric oxide synthetase (iNOS) and production of nitric oxide (NO) by pancreatic islet cells has been suggested as one potential mechanism for beta cell destruction. In this study, we investigated the role of iNOS and NO in islet primary non‐function. Islets were assessed for their function, viability and expression of iNOS. Adult rat and pig islets isolated by collagenase digestion and fetal pig pancreas (FPP) grafts isolated by collagenase digestion or high oxygen culture were transplanted into C57BL6 mice and nude mice. iNOS protein was detected by immunohistochemistry. iNOS protein was found in normal rat and pig pancreas and adult rat and pig islets that were isolated by collagenase digestion and transplanted into either C57BL6 mice or nude mice. iNOS was not detected in fetal pig islet grafts, regardless of whether collagenase was used in the isolation process. In adult pig islet grafts, the presence of iNOS protein correlated with high levels of islet cell apoptosis and primary non‐function. Despite the persistent presence of iNOS in rat islets, there was no evidence that it had a deleterious effect on rat islet viability, or function. Therefore, in isolated adult pig islets, there was a correlation between iNOS expression and apoptosis, suggesting that iNOS activation may be deleterious to the adult pig islets. However, other factors such as the fragility of the islet capsule may be equally important. By contrast, fetal pig islets did not express iNOS and this may be an important reason for their enhanced viability when compared with adult islet tissue.
Comparative study of efficacy of removal of anti‐ABO and anti‐gal antibodies by double filtration plasmapheresis
Authors: Kobayashi Takaaki , Yokoyama Itsuo , Morozumi Kunio , Nagasaka Takaharu , Hayashi Shuji , Uchida Kazuharu , Takagi Hiroshi , Nakao Akimasa
Published: March 2003

Abstract: Successful clinical ABO‐incompatible renal transplantation has been achieved by the removal of anti‐A or anti‐B antibodies using double filtration plasmapheresis (DFPP). We have compared changes in the levels of anti‐donor antibodies and the histopathology of the renal grafts following human ABO‐incompatible allotransplantation and pig‐to‐baboon xenotransplantation using pretransplantDFPP.

DFPP was performed on days −6, −4, −2 and −1 before the ABO‐incompatible transplants (n = 25) and on days −2 and 0 (immediately before reperfusion) in the xenotransplants (n = 4). In two baboons (XenoTx Group I) the extent of antibody removal was comparable to that in the ABO‐incompatible patients, and an even greater level of removal was achieved in another two baboons (XenoTx Group II). Anti‐A and anti‐B and anti‐pig IgM and IgG antibodies were measured by flow cytometry.

All clinical ABO‐incompatible renal grafts are functioning, except two which were lost from recurrence of the original disease or from chronic rejection. Three other grafts underwent humoral rejection episodes, which were successfully treated. DFPP reduced the mean anti‐A/B IgM and IgG antibody levels to 8% and 13% of pre‐treatment levels, respectively. After kidney transplantation, they were maintained at 37% and 46% of pre‐DFPP level. No antibody binding to the transplanted kidney was detected at any time (1 h to 2 yr) after ABO‐incompatible allotransplantation. In contrast, in XenoTx Group I, the same extent of antibody removal (90%) prevented hyperacute rejection, but the two grafts were rejected on days 6 and 7, respectively, from acute vascular rejection. In XenoTx Group II, the additional DFPP that was required to deplete the remaining 10% of anti‐pig antibody was poorly tolerated and the two baboons died 4 h and 2 days, respectively, after renal transplantation. Although anti‐pig IgM antibodies were reduced to 2% of pre‐treatment level, IgM and C3 binding were detected in the graft as early as 1 h post‐transplantation.

These data suggest that the concentration of xeno‐antigen epitopes expressed on pig organs may need to be reduced by genetic engineering to the much lower level of blood group A/B antigens on human kidneys if discordant xenotransplantation is to besuccessful.
Removal of bowel aerobic gram‐negative bacteria is more effective than immunosuppression with cyclophosphamide and steroids to decrease natural α‐Galactosyl IgG antibodies
Authors: Mañez Rafael , Blanco Francisco J. , Díaz Inmaculada , Centeno Alberto , Lopez‐Pelaez Eduardo , Hermida Manuel , Davies Hugh F. S. , Katopodis Andreas
Published: March 2003

Abstract: Natural α‐Galactosyl (Gal) antibodies play an important role in the rejection of pig xenografts by humans and Old World monkeys. In this study we investigate the efficacy of two different strategies to reduce the serum level of natural anti‐Gal antibodies. On the one hand, removal of aerobic gram‐negative bacteria from the intestinal flora, because anti‐Gal antibodies appear to be produced as a result of the continuous sensitization by these microorganisms. On the other hand, we studied the effect on these antibodies of an immunosuppressive regimen of cyclophosphamide and steroids. Ten baboons were treated for three months with norfloxacin (Nor Group; n = 6) or cyclophosphamide and steroids (CyP Group; n = 4). A further four baboons did not receive any treatment (Control Group). Aerobic gram‐negative bacteria became negative in stools of the Nor Group after two weeks of treatment, and remained undetectable until week 7. Thereafter, a gradual increase on the fecal concentration of aerobic gram‐negative bacteria was observed despite the norfloxacin treatment. The mean anti‐Gal IgG in the Nor Group gradually declined from week 4 to 9 to a mean of 62.7 ± 18% of the baseline level, and during this period were significantly lower than in the CyP (P < 0.02) and the Control (P < 0.05) groups. No differences were observed between the three groups during the 16 weeks of follow‐up in serum levels of anti‐Gal IgM, hemolytic anti‐pig antibodies, total IgG, IgM and IgA. In conclusion, removal of normal aerobic gram‐negative bacteria from the intestinal flora is more effective than immunosuppression with CyP and steroids in reducing the level of natural anti‐Gal antibodies, although there is no discernible effect on IgM antibodies.
Sexual character intensity and its relationship to breeding timing, fecundity and mate choice in the great cormorant Phalacrocorax carbo lucidus
Authors: Childress R. Brooks , Bennun Leon A.
Published: March 2003

Reproductive success and the intensity of five separate seasonal sexual characters, expressed similarly in both sexes and likely to be dependent on age and/or individual condition, were documented at a colony of great cormorants at Lake Naivasha, Kenya (00°46′ S, 36°22′ E) in 1996. The characters assessed were head filoplumes, thigh patch feathers, colour of cheek, neck and upper breast plumage, colour of gular skin, and colour of suborbital skin. More intensely developed sexual characters at the time of pair formation were associated with significantly earlier breeding. Pairs that bred earlier fledged significantly more chicks than those breeding later. However, correlations between the number of chicks fledged and the intensity of the parents’ sexual characters at pair formation were generally weak and not significant. An exception was the colour of the cheek, foreneck and upper breast plumage: males (but not females) with the darkest plumage in these areas fledged significantly more chicks than others. Correlations between paired male and female sexual character intensity were weak, and significant only in the case of suborbital skin colour. Other factors may have been more important than these characters in influencing mate selection.
Behavioural and physiological effects of absence of ultraviolet wavelengths on European starlings Sturnus vulgaris
Authors: Maddocks Sam A. , Goldsmith Arthur R. , Cuthill Innes C.
Published: March 2003

As ultraviolet wavelengths are used in normal avian colour perception, the maintenance of captive birds under artificial lighting (which is normally UV‐deficient) may have welfare implications. European starling Sturnus vulgaris juveniles kept in UV‐deficient light environments had significantly higher basal plasma corticosterone concentrations than those kept under full spectrum lighting, in the second of two experimental blocks. UV‐deficient conditions also led to significant changes in behaviour indicative of escape (less perching and more hanging on the cage and pecking at it). However, the birds from the first block, where the interval between transfer to the experimental set‐up from the wild was short (2 days), showed significantly higher basal and maximum plasma corticosterone concentrations than those in the second block and no additional effect of light environment on either corticosterone or behaviour. We hypothesise that this difference between blocks was due to the overriding initial stress of being in captivity swamping any treatment effects. Capture stress had declined in the second set of birds, which entered the experiment after 7–14 days in captivity. Stress effects of UV‐deficient lighting appear small relative to the overall impact of captivity, but may nevertheless become apparent after the initial effects of capture subside.
Rare extra‐pair fertilizations in the semi‐colonially breeding linnet Carduelis cannabina
Authors: Bønløkke‐Pedersen Jesper , Drachmann Jan , Frydenberg Jane , Boomsma Jacobus J.
Published: March 2003

Microsatellite analysis was used to analyse the level of extra‐pair paternity (EPP) in the semi‐colonially breeding linnet Carduelis cannabina in Denmark. During the breeding seasons of 1998 and 1999 EPP accounted for only 3.8% of young (4/106, 95% CL=1–13%). These extra‐pair young were found in 9.1% of the broods (2/22, 95% CL=1–29%). We hypothesize that this low level of EPP is due to an efficient use of both mate guarding and frequent copulations as paternity guards. However, experimental tests with temporary detainment of males would be needed to establish whether there is a causal relationship between the low EPP level and the double paternity guard.
A longitudinal evaluation of pulpal pain during orthodontic tooth movement
Authors: Leavitt AH , King GJ , Ramsay DS , Jackson DL
Published: March 2003

Objectives – To examine the longitudinal changes in pulpal sensitivity to electrical stimulation and the relationship to pulpal sensitivity as measured by electrical stimulation and subjective reports of tooth pain after archwire insertion.

Design – Non‐randomized, prospective trial, with matched controls.

Setting and Sample Population – Regional Clinical Dental Research Center at the University of Washington School of Dentistry. Eighteen adult subjects of age 13–37 years. Nine experimental subjects planned for orthodontic treatment. Nine control subjects matched for gender and age who did not have orthodontic treatment.

Experimental Variable – Fixed orthodontic appliances and initial archwire placement in experimental subjects compared with `no treatment' control subjects.

Outcome Measure – Subjective assessments of orthodontic tooth pain were made using visual analogue scales. Electrically evoked detection and pain thresholds were determined using a computer‐controlled tooth stimulator. Data were gathered at five time points: after bracket placement (baseline), 1 h after placement of initial archwires, 1 day after archwire placement, 1 week after archwire placement, and 1 month after archwire placement. Comparable time intervals were used for the `no treatment' control subjects.

Results – Subjective ratings of treatment‐evoked tooth pain in the experimental group were the greatest at the post‐archwire day 1 observation and progressively decreased for the remaining observations. Control subjects reported little pain at any of these observation times. The detection and pain threshold changes from baseline showed no statistical differences over time or between groups. While not statistically significant, a trend was noted where reports of greater orthodontic tooth pain were associated with increased sensitivity to electrical stimulation (i.e. lower detection and pain thresholds).

Conclusion – Orthodontic patients experience significant pain and discomfort 1 day after initial archwire placement (i.e. activation). Future research should investigate whether self‐reports of treatment‐evoked tooth pain intensity are associated with pulpal sensitivity.
Regional size differences in four commonly used cephalometric atlases: the Ann Arbor, Cleveland (Bolton), London (UK), and Philadelphia atlases compared
Authors: Dibbets JMH , Nolte K
Published: March 2003

Authors– Dibbets JMH, Nolte K

Objective– To explore regional influence on size in roentgenocephalometric atlases.

Design– Comparisons of the size of 10 linear distances in four atlases from geographically different regions, i.e. Ann Arbor Michigan, Cleveland Ohio, Philadelphia Pennsylvania and London, UK.

Distances compared– anterior cranial base length (S–N), posterior cranial base length (S–Ba), total face height (N–Me), upper face height (N–ANS), lower face height (ANS–Me), mandibular diagonal (Ar–Gn), corpus length (Go–Pg), ramus height (Ar–Go), maxillary length (SNP–SNA), posterior face height (S–Go).

Results– Correction for enlargement appeared to be a necessity before distances could be compared. After correction for enlargement, the anterior cranial base was longest in Ann Arbor, lower face height smallest in Cleveland (Bolton standards) and the maxilla was shortest in Philadelphia.

Conclusion– Regional size variance in cephalometric data cannot be ignored.
p75/AIRM1 and CD33, two sialoadhesin receptors that regulate the proliferation or the survival of normal and leukemic myeloid cells
Authors: Mingari Maria Cristina , Vitale Chiara , Romagnani Chiara , Falco Michela , Moretta Lorenzo
Published: March 2003

Summary: Inhibitory receptors originally identified in natural killer (NK) cells have also been detected in other leukocyte types, thus suggesting that they may play a more general role in the control of leukocyte function. Here we report data on p75/adhesion receptor molecule 1 (AIRM1), a surface inhibitory receptor of the sialoadhesin family originally identified in NK cells that is also expressed by normal and leukemic myeloid cells. Given the homology between p75/AIRM1 and CD33, we also reanalyzed CD33, a major myeloid marker of still unknown function. We discuss recent data indicating that engagement of p75/AIRM1 or CD33 sharply inhibits the in vitro proliferation/differentiation of CD34+ myeloid precursors induced by stem cell factor and granulocyte–macrophage colony‐stimulating factor. Importantly, a similar in vitro inhibitory effect occurs in monocyte/macrophages as well as in chronic or acute myeloid leukemias. While CD33 appears to act via the induction of apoptosis, p75/AIRM1 blocks cell proliferation but does not appear to induce apoptosis. A synergistic effect in the induction of apoptosis has also been documented between antibodies specific for CD33 and the chemotherapic agent etoposide. Taken together, the use of appropriate ligands against CD33 or p75/AIRM1 may represent a new therapeutic tool for treatment of myeloid leukemias or diseases characterized by overwhelming macrophage activation.

This work was supported by grants awarded by Associazione Italiana per la Ricerca sul Cancro (A.I.R.C.), Istituto Superiore di Sanità (I.S.S.), Ministero della Sanità, and Ministero dell’Università e della Ricerca Scientifica e Tecnologica (M.U.R.S.T.), MURST 5%–CNR Biotechnology program 95/95 and Consiglio Nazionale delle Ricerche, Progetto Finalizzato Biotecnologie.
The pas de deux of viruses and CD8 T cells
Authors: Doherty Peter C.
Published: March 2003

Summary: The vertebrate immune system has evolved to deal with parasitic life forms, so it is hardly surprising that experiments with pathogens have proved illuminating for immunology. Those of us who have worked for years with infectious processes are acutely conscious that we do little more than probe the vast ‘experiment of nature.’ There is no place for doctrinaire rigidity in this extraordinarily complex area of biology. Though we have obviously tried to do rational experiments, much of the novelty that has been brought in to immunology from the analysis of the virus‐specific host response has, in a very real sense, been the product of what we now call ‘discovery science’. The following relates some of the research that I was involved in personally and attempts to put it in the context of both the history of the field and the events of the time. Virus infections, particularly HIV, pose enormous challenges for the future. It is generally helpful to know a little of what went before.
Uncertainties − discrepancies in immunology
Authors: Zinkernagel Rolf M.
Published: March 2003

Summary: The many immunological observations and results from in‐vitro or in‐vivo experiments vary, and their interpretations differ enormously. A major problem is that within a normal distribution of biological phenomena, which are measurable with many methods, virtually anything is possible. Within a coevolutionary context, the definition of biologically relevant thresholds is an important key to improve our understanding of weaknesses and strengths of the immune system. This review is a personal view, comparing textbook rules and experiments using model antigens with observations on immunity against infections or tumors to critically evaluate our perception and understanding of specificity, affinity maturation, antigen presentation, selection of the class of the immune response, immunological memory and protective immunity, positive selection of T cells and self/nonself discrimination.
Glycosylation in the control of selectin counter‐receptor structure and function
Authors: Lowe John B.
Published: March 2003

Summary: Leukocyte trafficking is characterized by sequential cell adhesion and activation events that deliver specific leukocyte subsets to distinct extravascular locations under different pathophysiological circumstances. E‐, P‐ and/or L‐selectin‐dependent leukocyte–endothelial cell adhesive interactions contribute essentially to this process. Selectin counter‐receptor activity on leukocyte and high endothelial venules is borne by specific glycoproteins whose ability to support adhesion requires specific post‐translational modifications. These modifications are typified by serine/threonine‐linked oligosaccharides capped with the sialyl Lewis x moiety, an α2–3sialylated, α1‐3ucosylated tetrasaccharide synthesized by specific glycosyltransferases. Recent advances in glycan structure analysis and in characterizing mice with targeted deletions of glycosyltransferase and sulfotransferase genes discloses an essential role for 6‐O GlcNAc sulfate modification of the sialyl Lewis x tetrasaccharide in L‐selectin counter‐receptor activity. Related studies identify novel extended Core 1 type O‐glycans bearing the 6‐sulfosialyl Lewis x moiety, define the molecular nature of the MECA‐79 epitope, and disclose a requirement for the α1‐3fucosyltransferases FucT‐IV and FucT‐VII in the elaboration of L‐selectin counter‐receptor activities. Parallel studies also demonstrate that these 2 fucosyltransferases, a core 2 GlcNAc transferase, and core 2‐type sialyl Lewis x determinants make essential contributions to leukocyte P‐selectin counter‐receptor activity, and figure prominently in the control of leukocyte E‐selectin counter‐receptor activity.
α4 integrins and the immune response
Authors: Rose David M. , Han Jaewon , Ginsberg Mark H.
Published: March 2003

Summary: The α4 integrins (α4β1 and α4β7) play multiple roles in the immune system. α4 integrins impact hematopoiesis, leukocyte trafficking in immune surveillance and inflammation, and leukocyte activation and survival. To perform these functions, α4 integrins act as both adhesive and signaling receptors. Paxillin, a signaling adapter molecule, binds directly to the α4 subunit cytoplasmic domain, and its binding is regulated by serine phosphorylation of the α4 subunit. This regulated interaction of paxillin with the α4 subunit is likely to regulate the diverse functions of α4 integrins in the immune system. Furthermore, this protein–protein interaction may provide novel targets for the modulation of the immune response.
Tumor‐specific shared antigenic peptides recognized by human T cells
Authors: Van Der Bruggen Pierre , Zhang Yi , Chaux Pascal , Stroobant Vincent , Panichelli Christophe , Schultz Erwin S. , Chapiro Jacques , Van den Eynde Benoît J. , Brasseur Francis , Boon Thierry
Published: March 2003

Summary: The first tumor‐specific shared antigens and the cancer‐germline genes that code for these antigens were identified with antitumor cytolytic T lymphocytes obtained from cancer patients. A few HLA class I‐restricted antigenic peptides were identified by this ‘direct approach’. A large set of additional cancer‐germline genes have now been identified by purely genetic approaches or by screening tumor cDNA expression libraries with the serum of cancer patients. As a result, a vast number of sequences are known that can code for tumor‐specific shared antigens, but most of the encoded antigenic peptides have not yet been identified. We review here recent ‘reverse immunology’ approaches for the identification of new antigenic peptides. They are based on in vitro stimulation of naive T cells with dendritic cells that have either been loaded with a cancer‐germline protein or that have been transduced with viruses carrying cancer‐germline coding sequences. These approaches have led to the identification of many new antigenic peptides presented by class I or class II molecules. We also describe some aspects of the processing and presentation of these antigenic peptides.
A study of graft versus host disease using bile duct implants under the kidney capsule
Authors: Hardy C. L. , Morahan G. , Bhathal P. S.
Published: March 2003

Abstract: Aims/Background: Graft versus host disease (GVHD) following histoincompatible bone marrow transplantation may be modelled experimentally using irradiated metallothionein promoter‐H‐2Kb transgenic mice (MET‐Kb mice), reconstituted with syngeneic non‐transgenic spleen and lymph node (LN) cells. In this model, inflammation peaks at 3 weeks post‐reconstitution, but resolves by 3 months, and is focussed on portal tracts and bile ducts (BD). The aim of this study was to determine if transgene‐expressing hepatocytes play a role in the immune response, why portal tracts are selectively targeted, and which cell types are involved. Methods: Intrahepatic BD (IHBD) with attached hepatocytes, or extrahepatic BD (EHBD) devoid of hepatoctyes, were isolated from MET‐Kb mice and implanted under the kidney capsule of transgenic (syngeneic) and congenic (allogeneic) mice. Three weeks post‐implantation, BD were scored histologically for rejection or survival, and stained for various cell‐surface molecules. Results: Generally, IHBD survived better than EHBD, and T cells were the predominant infiltrating cell type in both implants. Both types of implants undergoing rejection expressed intercellular adhesion molecule‐1 (ICAM‐1) and leukocyte function antigen‐1 (LFA‐1) at high density; BD and the underlying kidney parenchyma also expressed class I and II major histocompatibility complex (MHC). Conclusions: The rejection of both groups of implants by congenic recipients suggests that BD from MET‐Kb mice express the transgene, but the reason for the selective targeting of portal tracts rather than transgene‐expressing hepatocytes remains unclear. One possible explanation is that dendritic cells/antigen‐presenting cells (DC/APC) in portal tracts, which express high levels of MHC and co‐stimulatory molecules, are the primary targets, and that BD are infiltrated and destroyed as ‘bystanders’.
Reduced hepatic content of dehydroepiandrosterone sulphotransferase in chronic liver diseases
Authors: Elekima Obadiah T. Lulu , Mills Charles O. , Ahmad Afshan , Skinner Gordon R. B. , Ramsden David B. , Bown Jonathan , Young Tom W. , Elias Elwyn
Published: March 2003

Abstract: Aims/Background: Dehydroepiandrosterone sulphotransferase (DHEA ST) is the enzyme responsible for sulphation of lithocholic acid and other potentially hepatotoxic steroids. We have previously shown that DHEA ST activity is reduced in cytosol of liver from miscellaneous patients with chronic liver disease. The aim of this study was to investigate the cause of diminished sulphotransferase activity in order to further our understanding of whether a reduction in the ability to sulphate potentially hepatotoxic bile acids might play a role in the aetiology of primary cholestatic liver disease. Methods: We quantified DHEA ST in human liver cytosol from groups of patients with chronic liver diseases and normal subjects using a semiquantitative sodium dodecyl sulphate/polyacrylamide gel electrophoresis (SDS‐PAGE)/ immunoblotting method, and an enzyme‐linked immunosorbent assay (ELISA). We determined DHEA ST enzyme activity and correlated it with its immunoreactive concentration in 87 samples of human liver tissue. Results: DHEA ST activity and concentration were significantly reduced in primary biliary cirrhosis, primary sclerosing cholangitis, chronic active hepatitis and alcoholic cirrhosis but not in cryptogenic cirrhosis when compared to normal liver. There were no significant differences among disease groups. In all groups enzyme activity and cellular concentration correlated, suggesting that no aberrant non‐functional enzyme was produced. Conclusion: These results confirm that DHEA ST activity is diminished in liver disease and that the reduction is due to diminished enzyme presence. Further studies are required to show whether the reduction has any pathogenetic significance or is merely a consequence of disease.