bluuebunny/crossref_metadata_2025 huggingface dataset:
Differential expression and characterization of three metallothionein‐like genes in Cavendish banana (Musa acuminata)
Authors: Liu Pei , Goh Chong‐Jin , Loh Chiang‐Shiong , Pua Eng‐Chong
Published: March 2003

Metallothioneins (MTs) are cysteine‐rich polypeptides that are involved in metal detoxification and homeostasis in both prokaryotes and eukaryotes. In this study, we report the isolation and characterization of three members (MT2A, MT2B and MT3) of the MT‐like gene family from ripening banana fruit and their differential expression in various banana organs and during fruit development and ripening. All members of the MT‐like gene encode small cysteine‐rich polypeptides of 65–79 amino acid residues. MT2A shared a high sequence similarity (54–77%) with several type‐2 MTs in plants, while MT3 was highly homologous (51–61%) with type‐3 MTs. The three members expressed differentially in various organs but transcripts were generally more abundant in reproductive than vegetative organs. During fruit development, the MT2A transcript was barely detectable in ovary but increased to a high level in young fruit at 20 days after shooting (DAS) and declined gradually thereafter as fruit developed. In contrast, both MT2B and MT3 expressed poorly in young fruits (20–60 DAS) and transcripts were detected only in fruits at later stages of development. As ripening progressed, expression of MT2A decreased but that of MT3 increased. Expression of MT members during ripening appeared to be differentially regulated by ethylene, whose levels were low in FG and TY fruit but surged climacteristically in MG and declined sharply as ripening advanced further. Exogenous application of ethylene at 5 ppm or higher concentrations down‐regulated MT2A expression and the inhibitory effect of ethylene could be partially suppressed by the presence of norbornadiene, an inhibitor of ethylene action. Ethylene had no effect on transcript accumulation of MT2B and MT3. However, MT3 expression was greatly enhanced in response to metals such as CdSO4, CuSO4 and ZnSO4. These results suggest that increased MT3 expression may be associated with excess metal ions present in ripening fruit tissues. This study also provided evidence, for the first time, that ethylene and metals play a regulatory role in expression of MT‐like genes in banana.
Ozone tolerance in snap bean is associated with elevated ascorbic acid in the leaf apoplast
Authors: Burkey Kent O. , Eason Gwendolyn
Published: March 2003

Ascorbic acid (AA) in the leaf apoplast has the potential to limit ozone injury by participating in reactions that detoxify ozone and reactive oxygen intermediates and thus prevent plasma membrane damage. Genotypes of snap bean (Phaseolus vulgaris L) were compared in controlled environments and in open‐top field chambers to assess the relationship between extracellular AA content and ozone tolerance. Vacuum infiltration methods were employed to separate leaf AA into extracellular and intracellular fractions. For plants grown in controlled environments at low ozone concentration (4 nmol mol−1 ozone), leaf apoplast AA was significantly higher in tolerant genotypes (300–400 nmol g−1 FW) compared with sensitive genotypes (approximately 50 nmol g−1 FW), evidence that ozone tolerance is associated with elevated extracellular AA. For the open top chamber study, plants were grown in pots under charcoal‐filtered air (CF) conditions and then either maintained under CF conditions (29 nmol mol−1 ozone) or exposed to elevated ozone (67 nmol mol−1 ozone). Following an 8‐day treatment period, leaf apoplast AA was in the range of 100–190 nmol g−1 FW for all genotypes, but no relationship was observed between apoplast AA content and ozone tolerance. The contrasting results in the two studies demonstrated a potential limitation in the interpretation of extracellular AA data. Apoplast AA levels presumably reflect the steady‐state condition between supply from the cytoplasm and utilization within the cell wall. The capacity to detoxify ozone in the extracellular space may be underestimated under elevated ozone conditions where the dynamics of AA supply and utilization are not adequately represented by a steady‐state measurement.
Effects of salinity stress on photosystem II function in cyanobacterial Spirulina platensis cells
Authors: Lu Congming , Vonshak Avigad
Published: March 2003

The changes in PSII photochemistry in Spirulina platensis cells exposed to salinity stress (0–0.8 M NaCl) for 12 h were studied. Salinity stress induced a decrease in oxygen evolution activity, which correlated with the decrease in the quantum yield of PSII electron transport (ΦPSII). Phycocyanin content decreased significantly while chlorophyll content remained unchanged in salt‐stressed cells. Salinity stress induced an increase in non‐photochemical quenching (qN) and a decrease in photochemical quenching (qP). Analyses of the polyphasic fluorescence transients (OJIP) showed that with the increase in salt concentration, the fluorescence yield at the phases J, I and P declined sharply and the transient almost levelled off at salt concentration of 0.8 M NaCl. The effects of DCMU on the polyphasic rise of fluorescence transients decreased significantly. Salinity stress resulted in a decrease in the efficiency of electron transfer from QA− to QB. The slope at the origin of the relative variable fluorescence curves (dV/dto) and the relative variable fluorescence at phase J (VJ) increased in the absence of DCMU, but decreased in the presence of DCMU. The shape of the relative variable fluorescence transients in salt‐stressed cells was comparable to that of the control cells incubated with DCMU. The results in this study suggest that salt stress inhibited the electron transport at both donor and acceptor sides of PSII, resulted in damage to phycobilisome and shifted the distribution of excitation energy in favour of PSI.
Maize replicative α‐type DNA polymerase: separation of polymerase and primase activities and recognition of primase subunits
Authors: García Elpidio , Laquel Patricia , Castroviejo Michel , Plasencia Javier , Vázquez‐Ramos Jorge M.
Published: March 2003

DNA polymerase and DNA primase activities in the maize α‐type DNA polymerase 2 were dissociated and DNA polymerase‐free DNA primase was studied. DNA primase synthesized primers that were 8–34 nucleotides long, with more intense bands at 15–17 nucleotides in length. DNA polymerase 1 (a putative δ‐type enzyme) or DNA polymerase 2 were assayed after template‐priming with purified DNA primase and showed a differential use of templates: whereas DNA polymerase 2 used a polydT template more efficiently than a natural template, DNA polymerase 1 used both of them poorly. The molecular size of DNA primase was estimated to be 68 kDa by gel filtration, western blotting and by a DNA primase ‘trapping’ assay.
Non‐enzymatic protein modification by the Maillard reaction reduces the activities of scavenging enzymes in Vigna radiata
Authors: Murthy U. M. Narayana , Liang Yongheng , Kumar Prakash P. , Sun Wendell Q.
Published: March 2003

The non‐enzymatic modification of proteins through the Maillard reaction plays an important role in the loss of seed viability during seed storage. In the present study we examined whether the Maillard reaction reduces the activities of scavenging enzymes in Vigna radiata (mung bean) seeds during storage. Seeds were stored under various conditions for different duration. Maillard products were monitored by measuring protein fluorescence, and the activities of glutathione reductase (GR), superoxide dismutase (SOD), ascorbate peroxidase (APX), catalase (CAT) and peroxidase (POX) were determined. The accumulation of Maillard products in seed axes increased during storage with increasing moisture content and temperature, and was correlated with the decline in seed vigour. The activities of GR, CAT and APX decreased in proportion to the increase in Maillard products at all the moisture contents and temperatures tested. These enzymatic changes were also correlated with seed vigour. However, the activities of SOD and POX remained unchanged and appeared to be less sensitive to the Maillard reaction.
CO2‐concentrating mechanisms in Egeria densa, a submersed aquatic plant
Authors: Lara María V. , Casati Paula , Andreo Carlos S.
Published: March 2003

Egeria densa is an aquatic higher plant which has developed different mechanisms to deal with photosynthesis under conditions of low CO2 availability. On the one hand it shows leaf pH‐polarity, which has been proposed to be used for bicarbonate utilization. In this way, at high light intensities and low dissolved carbon concentration, this species generates a low pH at the adaxial leaf surface. This acidification shifts the equilibrium HCO3–/CO2 towards CO2, which enters the cell by passive diffusion. By this means, E. densa increases the concentration of CO2 available for photosynthesis inside the cells, when this gas is limiting. On the other hand, under stress conditions resulting from high temperature and high light intensities, it shows a biochemical adaptation with the induction of a C4‐like mechanism but without Kranz anatomy. Transfer from low to high temperature and light conditions induces increased levels of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) and NADP‐malic enzyme (NADP‐ME, EC 1.1.1.40), both key enzymes participating in the Hatch‐Slack cycle in plants with C4 metabolism. Moreover, one PEPC isoform, whose synthesis is induced by high temperature and light, is phosphorylated in the light, and changes in kinetic and regulatory properties are correlated with changes in the phosphorylation state of this enzyme. In the present review, we describe these two processes in this submersed angiosperm that appear to help it perform photosynthesis under conditions of extreme temperatures and high light intensities.
Overexpression of a bacterial indole‐3‐acetyl‐l‐aspartic acid hydrolase in Arabidopsis thaliana
Authors: Tam Yuen Yee , Normanly Jennifer
Published: March 2003

Transgenic Arabidopsis lines (ecotype Col‐0) carrying the Enterobacter agglomerans IaaspH gene under CaMV 35S promoter control were more sensitive to exogenous indole‐3‐acetyl aspartic acid (IAA‐Asp) and metabolized [2′‐14C]IAA‐Asp more rapidly than control lines. Free IAA, total IAA and IAN levels in independent transgenic lines that accumulated IaaspH mRNA varied insignificantly from control levels, yet IAA‐Asp levels were significantly reduced. The transgenic lines were grown in a variety of conditions and subjected to morphometric analysis. All three lines showed statistically significant differences in rosette diameter (in soil), root and hypocotyl length (on agar). These effects were transient in some cases and did not manifest themselves under all growth conditions tried. The two independent lines with single T‐DNA insertions had lower seed set compared to control lines.
Differential gene expression in proteoid root clusters of white lupin (Lupinus albus)
Authors: Peñaloza Enrique , Gutierrez Ana , Martínez José , Muñoz Gastón , Bravo León A. , Corcuera Luis J.
Published: March 2003

Proteoid root clusters are induced by P deficiency in white lupin. In their mature stage, these roots excrete organic acids (mainly citrate), thus allowing this species to acquire P from sparingly soluble sources. To screen for P‐regulated genes expressed during the period of citrate efflux, an experimental model based on proteoid root clusters contrasting in citrate efflux was developed. The feasibility of this model in identifying differential gene expression was assessed over a population of mRNAs from P‐starved and P‐starved rescued proteoid root clusters, sampled 24 and 72 h after P addition to 24 days P‐starved white lupin. Approximately 1500 bands of cDNA were displayed by differential display of 21‐primer pair's combination; 52 differentially expressed bands, either up‐ or down‐regulated after P addition, were observed. Sequence analysis of 17 of them revealed that they represent distinct cDNAs. A subsample of seven cDNAs was analysed by northern‐blot, showing that six were truly differential products. Transcripts coding for enzymes involved in carbon flux (glyceraldehyde 3‐phosphate dehydrogenase), glycolytic bypass (phosphoenolpyruvate carboxylase), Pi recycling (sulpholipid synthase), and two unknown cDNAs were shown to be down‐regulated by P supply. Besides, an up‐regulated transcript coding for a putative auxin‐induced protein was identified, whereas P addition did not significantly affect expression of a transcript for cyclophilins. These results show the feasibility of using P‐starved and P‐starved rescued proteoid root clusters as an experimental model to detect and examine the molecular changes occurring in root clusters during the period of citrate efflux in white lupin.
Evidence for the direct 2β‐ and 3β‐hydroxylation of [2H2]GA20‐13‐O‐[6′‐2H2]glucoside in seedlings of Phaseolus coccineus
Authors: Schneider Gernot , Fuchs Petra , Schmidt Jürgen
Published: March 2003

[17‐2H2]GA20‐13‐O‐[6′‐2H2]glucoside was synthesized and applied to seedlings of Phaseolus coccineus L. After incubation for 72 h the conjugate metabolites were purified and shown by LC‐ESI‐tandem‐MS and GC‐MS to be [17‐2H2]GA1‐13‐O‐[6′‐2H2]glucoside and [17‐2H2]GA29‐13‐O‐[6′‐2H2]glucoside. This is the first evidence for the conversion of intact GA‐O‐glucosides, and represents an additional metabolic pathway of the gibberellin metabolism in P. coccineus L. The results indicate that intact GA‐O‐glucosides are accepted by 2‐ and 3‐oxidases in the plant.
4,4,4‐Trifluoro‐3‐(indole‐3‐)butyric acid promotes root elongation in Lactuca sativa independent of ethylene synthesis and pH
Authors: Zhang Nenggang , Hasenstein Karl H.
Published: March 2003

We studied the mode of action of 4,4,4‐trifluoro‐3‐ (indole‐3‐) butyric acid (TFIBA), a recently described root growth stimulator, on primary root growth of Lactuca sativa L. seedlings. TFIBA (100 µM) promoted elongation of primary roots by 40% in 72 h but inhibited hypocotyl growth by 35%. TFIBA induced root growth was independent of pH. TFIBA did not affect ethylene production, but reduced the inhibitory effect of ethylene on root elongation. TFIBA promoted root growth even in the presence of the ethylene biosynthesis inhibitor l‐α‐(2‐aminoethoxyvinyl)glycine. TFIBA and the ethylene‐binding inhibitor silver thiosulphate (STS) had a similar effect on root elongation. The results indicate that TFIBA‐stimulated root elongation was neither pH‐dependent nor related to inhibition of ethylene synthesis, but was possibly related to ethylene action.
Purine and pyrimidine biosynthesis in higher plants
Authors: Boldt Ralf , Zrenner Rita
Published: March 2003

Purine and pyrimidine nucleotides have important functions in a multitude of biochemical and developmental processes during the life cycle of a plant. In higher plants the processes of nucleotide metabolism are poorly understood, but it is in principle accepted that nucleotides are essential constituents of fundamental biological functions. Despite of its significance, higher plant nucleotide metabolism has been poorly explored during the last 10–20 years (Suzuki and Takahashi 1977, Schubert 1986, Wagner and Backer 1992). But considerable progress was made on purine biosynthesis in nodules of ureide producing tropical legumes, where IMP‐synthesis plays a dominant role in primary nitrogen metabolism (Atkins and Smith 2000, Smith and Atkins 2002). Besides these studies on tropical legumes, this review emphasises on progress made in analysing the function in planta of genes involved in purine and pyrimidine biosynthesis and their impact on metabolism and development.
Cryptococcal meningitis in renal transplant patients associated with environmental exposure
Authors: Kapoor A. , Flechner S.M. , O’Malley K. , Paolone D. , File, Jr. T.M. , Cutrona A.F.
Published: March 2003

Fungal infections in renal transplant recipients are less common than bacterial infections; however, the morbidity from fungal infections is high. There is limited information in the literature concerning post‐transplantation cryptococcal infection due to environmental exposure of patients living in high‐risk areas. We report three patients who were diagnosed with cryptococcal meningitis after kidney transplantation. Cryptococcal titers prior to transplant surgery were negative in all three patients. These patients all lived in rural areas and demonstrated evidence of environmental exposure leading to subsequent cryptococcal meningitis. All patients had exposure to pigeon and chicken excreta and, after treatment, two patients are alive and well with excellent allograft function. The third patient has marginal renal function but is currently not on dialysis. Early diagnosis is essential for salvage from these potentially lethal infections. Intense headache was a prominent feature in the clinical presentation of our patients, and should signal the need for early sampling and culture of spinal fluid. Meningismus was not present in any of our patients, even when other systemic symptoms were identified. We recommend a high index of suspicion post‐transplantation for all patients who may have environmental or occupational exposure to cryptococcus. If infection is detected quickly and treatment instituted promptly, patient recovery and allograft survival are possible. Long‐term therapy with fluconazole, a non‐nephrotoxic agent, should permit eradication of the infection with preservation of kidney function.
Differences between synthetic oligosaccharide immunoabsorbents in depletion capacity for xenoreactive anti‐Galα1–3Gal antibodies from human serum
Authors: Gerber Bernhard , Tinguely Caroline , Bovin Nicolai V. , Rieben Robert , Nydegger Urs E.
Published: March 2003

Abstract: Extracorporeal immunoabsorption for removal of anti‐Galα1–3Gal (anti‐Gal) antibodies in putative pig‐to‐human xenotransplantation is considered a major prophylactic measure to avoid hyperacute and acute vascular rejections. However, the efficacy of the procedure does depend on choosing the appropriate oligosaccharide epitopes for the binding of human anti‐Gal. The synthetic oligosaccharides Galα1–3Gal (B‐disaccharide, Bdi) and Galα1–3Galβ1–4Glc (‘type 6’ trisaccharide, Tri6), covalently coupled to Sepharose via polyacrylamide (Sorbents Bdi and –Tri6, respectively), as well as a mixture thereof (Sorbent Mix), were examined for their efficacy to absorb anti‐Gal from 20 human serum samples. Sorbent Bdi removed 81% of anti‐Gal IgM and 85% of –IgG when assessed on Bdi by ELISA, but only 49% of IgG and 75% of IgM when assessed on Tri6. Sorbent Tri6 and –Mix showed significantly better absorption capacities in so far as Sorbent Tri6 removed 65% of anti‐Gal IgM and 80% of –IgG as assessed on Bdi and 85% of IgM/87% of IgG when tested on Tri6, and Sorbent Mix absorbed > 90% anti‐Gal of both isotypes of either specificity. Direct hemagglutination of rabbit erythrocytes (ER) was reduced by 75% (median value, range 0–94%) and the median cytotoxicity to PK15 target cells by > 94% after absorption on Sorbent Mix. Neither the decrease in ER agglutination titers nor the reduction of PK15 cytotoxicity revealed significant differences between the three immunoabsorbents tested. The large variation ranges of absorption efficacies within the 20 tested sera suggest that “tailor‐made” immunoabsorption treatments may be needed for putative xenotransplant recipients.
Effect of cell surface concentration of human DAF on transgenic pig aortic endothelial cells on the degree of protection afforded against human complement deposition
Authors: Carrington Christine A. , Cruz Gabriela dos Santos
Published: March 2003

Abstract: Cultures of hDAF transgenic porcine aortic endothelial cells (TPAEs) with levels of cell surface hDAF expression between 2000 and 300 000 molecules per cell have been used to determine the relationship between expression of hDAF and protection from human complement deposition in an in vitro model. At concentrations below 45 000 molecules per cell, the relationship between hDAF expression and degree of protection conferred is linear. Concentrations of 123 000 molecules per cell and higher give maximal protection (60% reduction of susceptibility to neat human serum) in this model. It is concluded that increasing hDAF expression above that displayed by the A74 line of hDAF transgenic pigs (240 000 ± 15 000 molecules per cell) would not confer any additional benefit.
Modulation of the in vivo primate anti‐Gal response through administration of anti‐idiotypic antibodies
Authors: McMorrow Isabel M. , Buhler Leo , Treter Sarah , Neethling Francisca A. , Alwayn Ian P. J. , Comrack Christopher A. , Kitamura Hiroshi , Awwad Michel , DerSimonian Harout , Cooper David K. C. , Sachs David H. , LeGuern Christian
Published: March 2003

Polyclonal anti‐idiotypic antibodies (AIA) were generated against human Galα1,3Gal antibodies (anti‐Gal) isolated from a single donor. Specificity of the AIA was demonstrated by selective binding to anti‐Gal antibodies (Ab) and absence of reactivity to non‐Gal Ab. The idiotopes identified by AIA were present on anti‐Gal Ab from all of the human samples evaluated (n=59) as well as on pooled samples, demonstrating that a restricted number of dominant idiotopes characterized the human anti‐Gal Ab response. Furthermore, the AIA had cross‐species reactivity with baboon serum samples (n=19), suggesting that the overall shape of the anti‐Gal Ab combining site is conserved throughout the Old World primates and providing additional evidence of the limited heterogeneity of the anti‐Gal Ab repertoire. In order to evaluate the potential effect of AIA in the modulation of the anti‐Gal response in vivo, a baboon was injected with repeated doses of the purified AIA. Following AIA treatment, new Ab were generated that reduced Ab‐mediated cytotoxicity to porcine cells. Furthermore, administration of the AIA to a baboon prolonged the survival of intravenously infused pig hematopoietic cells when compared with their survival in a control baboon that did not receive prior AIA treatment but underwent a similar conditioning regimen.
Expression of xenogeneic MHC class II molecules in HLA‐DR+ and ‐DR– cells: influence of retrovirus vector design and cellular context
Authors: Denaro Maria , Kolber‐Simonds Donna , Schad Victoria , Muthukumar Shanthini , Germana Sharon , White‐Scharf Mary E. , Banerjee Papia T. , LeGuern Christian , Andersson Göran
Published: March 2003

We recently established that molecular chimeras of major histocompatibility complex (MHC) class II molecules, created via retroviral transfer of allogeneic class II cDNAs into bone marrow cells (BMCs), alleviated complications associated with mixed BMC chimeras while leading to T cell tolerance to renal grafts sharing the transferred class II. Initially demonstrated for allogeneic transplants in miniature swine, this concept was extended to T‐dependent antibody (Ab) responses to xenogeneic antigens (Ags) in the pig → baboon combination. Successful down‐regulation of T cell responses appeared, however, to be contingent on a tight lineage‐specific expression of transferred class II molecules. The present studies were, therefore, designed to evaluate the influence of construct design and cellular environment on expression of retrovirally transferred xenogeneic class II cDNAs. Proviral genomes for pig class II SLA‐DR expression, differing only at the marker neo(r) or enhanced green fluorescent protein (EGFP) gene, showed increased membrane SLA‐DR density on HLA‐DR– fibroblasts as well as HLA‐DR+, TF‐1 erythroleukemia cells. More importantly, HLA‐DR+ human B cell lines, although efficiently transduced with pig DR retroviruses, exhibited unstable surface pig DR. Surface pig DR– B cells, nevertheless, stimulated autologous human T cells pre‐sensitized to pig Ags, a proliferation likely occurring through presentation of class II‐derived peptides. Collectively, these data suggest that surface expression of transferred class II molecules is not related to the ability of recipient cells to synthesize xenogeneic class II molecules but rather to their Ag processing capacities.
Do artificial nests reveal relative nest predation risk for real nests?
Authors: Pärt Tomas , Wretenberg Johan
Published: March 2003

Present knowledge of the effects of nest predation on spatial distribution, habitat selection and community structure of birds is to a large extent based on results from experiments with artificial nests. Although nest predation risk is likely to differ between artificial and real nests, most previous studies of nest predation using artificial nests have been lacking a proper control. We investigated whether predation rates on artificial nests predicted those on real nests by simultaneously comparing the fate of real and artificial nests (containing quail Coturnix coturnix and plasticine eggs) in 92 territories of the northern wheatear Oenanthe oenanthe in 1996. We also investigated whether risk for artificial nests was related to relative average risk for real nests in these territories (based on data collected two years before and two years after the experiment). Nest predation on artificial nests did predict relative predation risk for real nests only when quail egg depredation was used as the criterion for artificial nest predation. Despite plasticine egg depredation being the most common type of predation it was not associated with predation risk for real nests. Small mice and vole species dominated among cases with only plasticine egg depredation, while predatory mammals and snakes destroyed most quail eggs in artificial nests and most eggs in real wheatear nests. The results suggest that artificial nests may only predict the risk for real nests when the nest predator species are similar among the two types of nest. Furthermore, our data suggest that small mice and vole species rarely depredate nests of mid‐sized passerine birds. Our results cast doubt on many previous conclusions based on experiments with artificial nests, since predation risk for such nests is likely to be uncorrelated with risk for real nests due to nest‐type‐specific differences in nest preying species.
Nest usurpation is an ‘edge effect’ for Carolina chickadees Poecile carolinensis
Authors: Doherty, Jr. Paul F. , Grubb, Jr. Thomas C.
Published: March 2003

During 1995–1997, we monitored Carolina chickadee Poecile carolinensis nests in a fragmented forest landscape in northcentral Ohio, USA. Nest success was positively correlated with woodlot area and most nest loss was due to nest destruction by house wrens Troglodytes aedon. During 1998 and 1999, we conducted an experiment in both large (>6.8 ha) and small (<6.8 ha) woodlots in which we gave chickadees a choice of nesting on edges of woodlots (preferred wren habitat) or in the center of woodlots. We found no difference in nest success between large and small woodlots, but regardless of woodlot size, nest success was lower on edges than in the center. In the experiment, 100% of nest loss was due to nest destruction by house wrens. Given a choice, Carolina chickadees preferred to nest centrally more often than on edges. These results suggest that in fragmented landscapes where house wrens are common, nest destruction by house wrens is a major cause of nest failure in the Carolina chickadee. Such edge‐dependent interspecific nest‐site usurpation has not been previously recognized as a potentially important selective factor in nest site selection.
Body mass regulation during incubation in female common eiders Somateria mollissima
Authors: Criscuolo François , Gabrielsen Geir W. , Gendner Jean‐Paul , Le Maho Yvon
Published: March 2003

We investigated changes in incubation behaviour induced by body fuel depletion in incubating female common eiders, which, in contrast to pelagic seabirds, fast despite being close to marine food sources. In the Svalbard Archipelago, electronic scales were placed under eider nests and the incubation of six birds was prolonged by using wax‐filled eggs. Based on changes in the rate of body mass loss in normally incubating females and in ten captive birds that did not incubate, body reserves neared depletion on average four days after hatching. During prolonged incubation, females took more frequent and longer recesses. Nest attentiveness consequently decreased, but was still high. In contrast to recesses during normal incubation, during which body mass of the birds decreased, mass remained constant during the recesses of prolonged incubation. The body stores of female eiders seemed to enable them to complete incubation with a limited safety margin. A further drop in body mass is avoided when a critical body mass is reached, because birds then start feeding enough to maintain mass while continuing incubation. Presumably, a similar mechanism will enable eiders to continue incubation when body reserves are prematurely depleted before hatching.
Mass loss in incubating Eurasian dotterel: adaptation or constraint?
Authors: Holt Sue , Whitfield D. Philip , Duncan Keith , Rae Stuart , Smith Rik D.
Published: March 2003

Body mass loss is frequently observed in breeding birds: whether this is an adaptive response to a change in the relative value of body stores and locomotion performance or a consequence of energetic constraint is still in debate. The male alone cares for most nests of the Eurasian dotterel Charadrius morinellus, although females assist at a proportion of nests. Energetic costs are probably high in the dotterel's arctic‐alpine environment and uniparental care restricts the foraging time available to meet these costs, so that incubating dotterel may have to fuel themselves partly using body stores. Nesting male dotterel lost 7.8% of their mass through the incubation period but were 6.8% heavier during periods of high food abundance. Males that were assisted in incubation by a female were 6.7% heavier than uniparental males. We conclude that, since dotterel were heavier when energetic constraints were lifted, mass loss through incubation was principally a consequence of energetic constraint, rather than adaptive mass optimisation.
The natural plasma testosterone profile of male blue tits during the breeding season and its relation to song output
Authors: Foerster Katharina , Poesel Angelika , Kunc Hansjörg , Kempenaers Bart
Published: March 2003

In male birds, the gonadal hormone testosterone (T) is known to influence territorial and mating behaviour. Plasma levels of T show seasonal fluctuations which vary in relation to mating system and social instability. First, we determined the natural T profile of male blue tits Parus caeruleus during the breeding season. We found that plasma levels of T increased at the onset of nest building. Thus, the increase in circulating T was not associated with territory establishment, nor with the fertile period of the males’ mates. In most individuals, T levels dropped to values close to zero during the period of chick feeding. Second, we investigated the relationship between plasma levels of T and male age, size, and singing behaviour. During the mating period, T levels did not differ between 1 yr old and older males and did not correlate with body size or condition. However, song output during the dawn chorus tended to be positively correlated with T levels. Therefore, if high T levels are costly, song output might be an honest indicator of male quality in blue tits. Finally, we show that plasma levels of T are significantly higher during the night than during the day. This pattern has also been observed in captive non‐passerine birds, but its functional significance remains unknown.
Mesiodistal size of deciduous teeth in subjects with unilateral cleft lip and palate
Authors: Jaksˇić N , Sˇćepan I , Glisˇić B , Stamenic E , Stamenković Z
Published: March 2003

The aim of this study was to investigate whether there was an association between presence of a cleft and reduced size of deciduous tooth on the cleft side. In this investigation, 58 study models of patients with unilateral cleft lip and palate with deciduous dentition were analyzed. The largest mesiodistal dimension of deciduous teeth was measured by a sliding caliper. The size of the same teeth on the side of the cleft and on the non‐cleft side was compared. The results of the investigation were statistically analyzed. A difference between the genders was found. In the sample of boys the lateral deciduous incisor and the second deciduous molars on the cleft side were smaller than those on the non‐cleft side, while in girls the central and lateral deciduous incisors were smaller on the cleft side than on the non‐cleft side. It was concluded that the presence of a unilateral cleft lip and palate was associated with smaller tooth size.
Deciduous tooth crown size and asymmetry in strabismic children
Authors: Heikkinen T , Alvesalo L , Tienari J
Published: March 2003

Structured Abstract

Authors –
Heikkinen T, Alvesalo L, Tienari J

Objectives –
To explore deciduous tooth crown dimensions in strabismic children and the relationship between the type of strabismus and tooth crown mesio‐distal (M‐D) and labio‐lingual (L‐L) size asymmetries.

Material –
Dental casts at mixed dentition of 2159 Collaborative Perinatal Study black and white children were measured, 123 of them strabismic at 1 year of age, age ranging from 6 to 12 years.

Methods– Directional and fluctuating asymmetries in antimeric teeth were explored in various types of strabismus having unilateral, bilateral or alternating expression. ANOVA and T‐square test were used for size comparisons and calculated asymmetries were explored by comparing the variances and Pearson correlations.

Results –
Strabismus was associated with significant M‐D size increase of deciduous maxillary canines in black boys and white girls, black girls had size reduction in their mandibular canine, but white boys were unaffected. Right side size dominance was found in the strabismic children in the lower second deciduous molar M‐D dimensions and in the children with alternating strabismus in their upper deciduous canine M‐D dimensions. Children with unilateral strabismus had random fluctuating dental asymmetry in their upper deciduous second molar L‐L dimensions when compared with healthy normals. Higher left‐right correlations were found in lower second deciduous molar dimensions in strabismic girls when compared with that in controls and in strabismic boys, suggesting better developmental canalization in female.

Conclusions –
Asymmetries in the head area, such as promoted here in strabismic children, may have associations with asymmetries in the dentition, focusing the embryonal origins and timing of developmental processes.
Randomized, double‐blind clinical trial, controlled with placebo, of the toxicology of chronic melatonin treatment
Authors: Seabra Maria de Lourdes V. , Bignotto Magda , Pinto Jr. Luciano R. , Tufik Sergio
Published: March 2003

The objective of the present study was to assess the toxicology of melatonin (10 mg), administered for 28 days to 40 volunteers randomly assigned to groups receiving either melatonin (N=30) or placebo (N=10) in a double‐blind fashion. The following measurements were performed: polysomnography (PSG), laboratory examinations, including complete blood count, urinalysis, sodium, potassium and calcium levels, total protein levels, albumin, blood glucose, triglycerides, total cholesterol, high‐density lipoprotein (HDL), low‐density lipoprotein (LDL), and very low‐density lipoprotein (VLDL), urea, creatinine, uric acid, glutamic‐oxalacetic transaminase (GOT), glutamic‐pyruvate transaminase (GPT), bilirubin, alkaline phosphatase, gama‐glutamic transaminase (GGT), T3, T4, TSH, LH/FSH, cortisol, and melatonin serum concentrations. In addition, the Epworth Somnolence Scale (ESS) and a sleep diary (SD) were also applied to the volunteers 1 wk before each PSG. In addition, the volunteers were asked about possible side effects (SE) that appeared during the treatment. The study was carried out according to the following timetable: Visit 0, filling out the term of consent and inclusion criteria; Visit 1, PSG, laboratory examinations, ESS, SD, melatonin serum concentrations; Visit 2, SD, melatonin serum concentrations, SE; Visit 3, melatonin serum concentrations, PSG, ESS, SE; Visit 4, laboratory examinations, SE, melatonin serum concentrations, SD; and Visit 5, PSG, ESS, SE. Analysis of the PSG showed a statistically significant reduction of stage 1 of sleep in the melatonin group. No other differences between the placebo and melatonin groups were obtained. In the present study we did not observe, according to the parameters analyzed, any toxicological effect that might compromise the use of melatonin at a dose of 10 mg for the period of time utilized in this study.
Some quantitative aspects of T‐cell repertoire selection: the requirement for regulatory T cells
Authors: Mason Don
Published: March 2003

Summary: How the adaptive immune system achieves self–non‐self discrimination is not well understood, and in this article consideration is given to some of the quantitative aspects of this problem. In particular, the modification of the T‐cell repertoire as a result of clonotypic deletion in the thymic cortex is discussed and shown to make a major contribution to the achievement of self‐tolerance. An evaluation is also made of the benefit of MHC restriction in preventing clonal deletion in MHC heterozygotes from being more profound than it is in homozygotes, despite the approximately twofold increase in the presentation of self‐peptides in the thymus in heterozygotes. The effect that receptor editing may have on the efficiency of positive selection is estimated. Finally, the conclusions from these considerations are used to suggest why a subset of T cells, the regulatory T cells, are required to control immune responses to certain self‐antigens. The potential value of regulatory T cells to the control of inflammation induced by pathogens is also briefly discussed.
Enhancing antitumor immune responses: intracellular peptide delivery and identification of MHC class II‐restricted tumor antigens
Authors: Wang Rong‐fu
Published: March 2003

Summary: The importance of T‐cell‐mediated antitumor immunity has been demonstrated in both animal models and human cancer therapy. The identification of major histocompatibility complex (MHC) class I‐restricted tumor antigens has generated a resurgence of interest in immunotherapy for cancer. However, recent studies suggest that therapeutic strategies that have mainly focused on the use of CD8+ T cells (and MHC class I‐restricted tumor antigens) may not be effective in eliminating cancer cells in patients. Novel strategies have been developed for enhancing T‐cell responses against cancer by prolonging antigen presentation of dendritic cells to T cells and the inclusion of MHC class II‐restricted tumor antigens. identification of MHC class II‐restricted tumor antigens, which are capable of stimulating CD4+ T cells, not only aids our understanding of the host immune responses against cancer antigens, but also provides opportunities for developing effective cancer vaccines.
Antigenicity and immunogenicity of Melan‐A/MART‐1 derived peptides as targets for tumor reactive CTL in human melanoma
Authors: Romero Pedro , Valmori Danila , Pittet Mikael J. , Zippelius Alfred , Rimoldi Donata , Lévy Frederic , Dutoit Valérie , Ayyoub Maha , Rubio‐Godoy Verena , Michielin Olivier , Guillaume Philippe , Batard Pascal , Luescher Immanuel F. , Lejeune Ferdy , Liénard Danielle , Rufer Nathalie , Dietrich Pierre‐Yves , Speiser Daniel E. , Cerottini Jean‐Charles
Published: March 2003

Summary: Some cancer patients mount spontaneous T‐ and B‐cell responses against their tumor cells. Autologous tumor reactive CD8 cytolytic T lymphocyte (CTL) and CD4 T‐cell clones as well as antibodies from these patients have been used for the identification of genes encoding the target antigens. This knowledge opened the way for new approaches to the immunotherapy of cancer. In this review, we describe the characterization of the structure‐function properties of the melanocyte/melanoma tumor antigen Melan‐A/MART‐1, the assessment of the T‐cell repertoire available against this antigen in healthy individuals, and the analysis of naturally acquired and/or vaccine‐induced CTL responses to this antigen in patients with metastatic melanoma.
Antigens derived from melanocyte differentiation proteins: self‐tolerance, autoimmunity, and use for cancer immunotherapy
Authors: Engelhard Victor H. , Bullock Timothy N. J. , Colella Teresa A. , Sheasley Stacey L. , Mullins David W.
Published: March 2003

Summary: A large set of peptide antigens presented by class I major histocompatibility complex (MHC) molecules on human and murine melanomas and recognized by CD8+ T cells have been defined. These peptides represent attractive candidates for the development of therapeutic and/or prophylactic approaches to treat this cancer. However, the majority of the peptides that are presented by multiple tumors and recognized by T cells from multiple patients arise from proteins that are also expressed in normal melanocytes. It is expected that immune responses to such peptides will be compromised by self‐tolerance or, alternatively, that stimulation of effective immune responses will be accompanied by autoimmune vitiligo. In this review, we describe a preclinical model to evaluate these issues and recent data to suggest that tolerance can be overcome to generate effective antitumor responses. This model also allows the rapid and systematic examination of parameters for the effective use of synthetic peptide vaccines.
The use of HLA class I tetramers to design a vaccination strategy for melanoma patients
Authors: Palmowski Michael , Salio Mariolina , Dunbar Rod P. , Cerundolo Vincenzo
Published: March 2003

Summary: Progress in human tumor immunology has recently been accelerated by new assays for antigen‐specific cytotoxic T lymphocytes (CTLs). We have used tetrameric MHC class I complexes (tetramers) to study melanoma‐specific CTLs both in vivo and in vitro, and have utilized the results to optimize vaccination strategies for patients. Tetramers have provided some of the best evidence to date that CTL responses against melanoma antigens arise spontaneously in patients. However, CTL responses to common (nonmutated) melanoma epitopes are generally weak or localized, and occur mostly in advanced metastatic disease, hence justifying early immunotherapeutic approaches. These observations led us to design a polyvalent vaccine construct for early administration to melanoma patients at high risk of progression. To compare possible vaccination protocols, we encoded this construct in several different vectors, and developed novel tetramers to track responses to the human melanoma epitopes in transgenic mice. Priming and boosting with the same poly‐epitope construct encoded in heterologous vectors led to the expansion of CTLs with a single dominant specificity. Separating the antigens for independent presentation by antigen‐presenting cells reversed the effect of immunodominance and induced a powerful polyvalent CTL response. These results provide important pointers for future vaccination trials, and tetramers will form an important tool in the immunomonitoring of these clinical studies.
Continuous infusion of prostaglandin E1 via the superior mesenteric artery can prevent hepatic injury in hepatic artery interruption through passive portal oxygenation
Authors: Sato Tsutomu , Kato Takeshi , Kurokawa Toshiaki , Yasui Ouki , Hiroshi Nanjo , Miyazawa Hideaki , Asanuma Yoshihiro , Koyama Kenji
Published: March 2003

Abstract: Aims/Background: Hepatic artery interruption (HAI) causes severe ischemic liver damage, especially following hepatopancreatobiliary surgery. In order to inhibit a decrease in oxygen delivery after HAI, continuous infusion of PGE1 via the superior mesenteric artery (SMA) was administered in pigs and changes in hepatic blood flow and oxygen delivery were investigated. Furthermore, its effectiveness in the prevention of liver injury was evaluated by histology and serum enzyme levels. Methods: Animals were subjected to HAI without PGE1 infusion (control group n=6) and to continuous infusion of PGE1 (0.02 μg/kg/min) into the SMA (PGE1 group n=6). Results and Conclusion: PGE1 infusion via the SMA not only increased the portal blood flow but also elevated the oxygen content of the portal blood. The reduction in oxygen delivery to the liver was 50% in the control group, and only 13% in the PGE1 group. Serum aspartate aminotransferase (AST) and lactate dehydrogenase (LDH) levels 24 h after HAI in the control group were 3415±1283 IU/L and 9839±2959 respectively while in the PGE1 group they were 939±426 IU/L and 5510±1545 IU/L respectively. Histological examination showed massive necrosis in the control group at 72 h but only focal liver cell necrosis in the PGE1 group. Based on this finding and the fact that this treatment can be performed easily and safely, continuous infusion of PGE1 via the SMA may be a useful intervention to prevent severe liver damage after hepatic artery interruption.
A prospective study of interferon therapy modified by pre‐treatment viral load in cirrhotic patients
Authors: Shiratori Yasushi , Moriyama Mistuhiko , Imazeki Fumio , Ohkubo Hitoshi , Tanaka Naohide , Arakawa Yasuyuki , Yoshida Haruhiko , Yokosuka Osamu , Shibuya Akitaka , Matsuzaki Kohei , Hashimoto Etsuko , Hayashi Naoaki , Hirata Keiichi , Ohashi Yasuo , Omata Masao ,   (Tokyo‐Chiba Hepatitis Research Group)
Published: March 2003

Abstract: Background/Aims: The relative role of hepatitis C virus (HCV) load and subtype as predictors of the efficacy of interferon therapy has been clarified in patients with chronic hepatitis C, but the effectiveness of interferon therapy in cirrhotic patients is still unclear. Methods: To resolve this issue, we undertook a multicenter, randomized, and prospective study of 114 cirrhotic patients with hepatitis C virus infection. The patients were selected to undergo two different periods (6 or 12 months) of IFN therapy according to viral load. Patients with “low” viral load (≤105.8 copies/ml serum) were randomly divided into three groups, receiving 6 or 9 million units (MU) interferon three times a week for 6 months (total dose: 468 or 702 MU), or of a modified regimen using 6MU of IFN over 6 months (total dose 564 MU), while patients with “high” viral load (≤106.3 copies/ml serum) were also randomly divided into two groups of 6 or 9 MU of IFN three times a week for 12 months (total dose: 936 or 1404 MU). Results: HCV‐RNA negativity rate at the completion of treatment with 6 or 9 MU IFN was 65% in patients with “low” viral load, in contrast to 14% in patients with “high” viral load. Sustained virological response was found in 40% of patients with “low” viral load irrespective of the three different regimens, in contrast to only 1 out of 35 patients (3%) with “high” viral load. Viral eradication was found in approximately 50% of patients having a low virus load (≤104.3 copies/ml) and with HCV subtype 2a. Univariate and multivariate analysis revealed that pretreatment viral load was a significant factor contributing to efficacy of IFN therapy. Conclusions: Sustained response was scarcely achieved in cirrhotic patients with high viral loads even after a 12‐month course of intensive IFN therapy. This result indicates that there is a certain cut‐off level of HCV RNA load which can not be eradicated.