bluuebunny/crossref_metadata_2025 huggingface dataset:
Three new alleles of IGHG2 and their prevalence in Danish Caucasians, Mozambican Blacks and Japanese
Authors: Hougs L. , Garred P. , Kawasaki T. , Kawasaki N. , Svejgaard A. , Barington T.
Published: November 2004

Abstract:  The human IGHG2 gene locus is polymorphic, encoding two known allotypes of IgG2: G2m(n–) and G2m(n+). The allele prevalence varies greatly between different ethnic groups and individual genotypes correlate with the level of plasma IgG2 and with antibody responses to certain polysaccharide antigens. In this study, we present three new alleles of IGHG2 (IGHG2*03, 04, and 05), and a complete sequence specific PCR typing system allowing discrimination between the different allotypes of IgG2. A hitherto unknown allotype, which we name G2m(ny), is encoded by IGHG2*04 and differs from G2m(n–) by asparagine rather than serine in CH1 residue 75 and by phenylalanine rather than leucine in CH1 residue 76 (EU numbering 192 and 193). The polymorphic residues are probably surface exposed near the hinge region. The same residues are also found in IgG1, IgG3, and IgG4, and G2m(ny) is therefore an isoallotype that probably arises by gene conversion within the heavy chain locus. The IGHG2*04 allele is present among Danish Caucasians with a low prevalence (2.5%), but was not found in Japanese or Mozambicans. The two other new alleles (IGHG2*03 and IGHG2*05) both encode the G2m(n–) allotype. The IGHG2*03 allele encodes most of the IgG2 of the G2m(n–) allotype in Danish Caucasians.
The chemical syntheses and bioactivities of novel peptide‐based endothelin antagonists
Authors: Yu W.‐S. , Zhao Y. ‐F. , Liang Y.‐J. , Liu K.‐L. , Fei G.‐S. , Wang H.
Published: November 2004

Abstract: Endothelin antagonists, novel tripeptides containing a series of unnatural amino acids, were synthesized and characterized. A linear peptide BQ‐485, perhydroazepin‐1‐yl‐l‐leucyl (1)‐d‐tryptophanyl (2)‐d‐tryptophan (3), was selected as the parent compound. The introduction of d‐Phe derivatives into these peptidic ET antagonists resulted in potent activity against the contraction of rat aortic smooth muscles induced by ET‐1 (10 nm) which activated the ET receptors. Among these compounds, 15 tripeptides had high enough antagonistic activity at the level of 10−7 mol/L (IC50). The activity of three compounds was 10−6 mol/L (IC50). These HIM‐CO‐Leu‐d‐Trp‐d‐Phe(‐R)‐OH compounds as ETA antagonists may provide a tool for the development of therapeutic agents in the treatment of putative ET‐1‐related disorders.
Modeling alternative binding registers of a minimal immunogenic peptide on two class II major histocompatibility complex (MHC II) molecules predicts polarized T‐cell receptor (TCR) contact positions
Authors: Murray J.S. , Schountz T. , Ford S.R. , Tawde M.D. , Murray J.S. , Jois S. D. S. , Siahaan T.J. , Brown J.C.
Published: November 2004

Abstract:  Several major histocompatibility complex class II (MHC II) complexes with known minimal immunogenic peptides have now been solved by X‐ray crystallography. Specificity pockets within the MHC II binding groove provide distinct peptide contacts that influence peptide conformation and define the binding register within different allelic MHC II molecules. Altering peptide ligands with respect to the residues that contact the T‐cell receptor (TCR) can drastically change the nature of the ensuing immune response. Here, we provide an example of how MHC II (I‐A) molecules may indirectly effect TCR contacts with a peptide and drive functionally distinct immune responses. We modeled the same immunogenic 12‐amino acid peptide into the binding grooves of two allelic MHC II molecules linked to distinct cytokine responses against the peptide. Surprisingly, the favored conformation of the peptide in each molecule was distinct with respect to the exposure of the N‐ or C‐terminus of the peptide above the MHC II binding groove. T‐cell clones derived from each allelic MHC II genotype were found to be allele‐restricted with respect to the recognition of these N‐ vs. C‐terminal residues on the bound peptide. Taken together, these data suggest that MHC II alleles may influence T‐cell functions by restricting TCR access to specific residues of the I‐A‐bound peptide. Thus, these data are of significance to diseases that display genetic linkage to specific MHC II alleles, e.g. type 1 diabetes and rheumatoid arthritis.
Evaluation of coagulation in pediatric bone marrow transplantation patients
Authors: Yenicesu İdil , Uçkan Duygu , Çetin Mualla , Tuncer A. M. , Tezcan İlhan , Gürgey Aytemiz
Published: November 2004

Abstract: A hypercoagulable state is frequently described in adult patients undergoing bone marrow transplantation (BMT). In this study, the coagulation profile of 29 children was prospectively investigated in the pre‐ and post‐transplant period. A significant rise in the activated partial thromboplastin time (aPTT) values was detected on days 7 and 14 after transplantation. Moreover, an increase in the d‐dimer level was also notable, regardless of the clinical condition of the patients. The other coagulation parameters investigated (i.e. protein S, protein C, anti‐thrombin III, factor VIII, von Willebrand factor, and prothrombin time) remained essentially unchanged. However, hyper‐fibrinogenemia was observed in all patients with chronic myeloid leukemia (CML) (n=5) before and after transplantation. In summary, in the present study pediatric bone marrow transplantation patients did not show a hyper‐coagulable state after marrow infusion. However, a significant rise in PTT and d‐dimer values were noted.
Indications, results, and complications of tacrolimus conversion in pediatric renal transplantation
Authors: Flynn Joseph T. , Bunchman Timothy E. , Sherbotie Joseph R.
Published: November 2004

Abstract:It is the practice of many pediatric renal transplant programs to ‘convert’ children taking cyclosporin A (CsA) to tacrolimus, although the indications for, outcome, and complications of this practice remain obscure. To better understand these aspects of tacrolimus ‘conversion’, a fax survey was sent to 119 North American pediatric renal transplant centers. Analyzable responses were received from 52 centers (44%), and included data from ≈ 1,815 pediatric renal transplants performed between 1991 and 98. Strong indications for tacrolimus conversion were: antibody‐resistant rejection, CsA‐resistant rejection, and CsA intolerance (strong indication in 72%, 65%, and 52% of centers, respectively). Steroid‐resistant rejection and cosmetic side‐effects were considered strong indications less often. Initial anti‐rejection therapy was usually increased corticosteroid dose (47/52 centers). Antibody therapy was most commonly used for steroid‐resistant rejection (44 centers). For steroid‐ and antibody‐resistant rejection, tacrolimus conversion was most common (33 centers). Tacrolimus conversion for antibody‐resistant rejection led to improvement of serum creatinine (SCr) in 27% of patients, stabilization of SCr in 46%, worsening of SCr in 11%, and graft loss in 16%. Reported complications after tacrolimus conversion included hyperglycemia, hyperkalemia, lymphoproliferative disorder, infection, and neurologic problems. We conclude that the major indication for tacrolimus conversion in pediatric transplant programs appears to be rejection. Outcome after tacrolimus conversion appears good, with the majority of patients experiencing stable or improved allograft function. These data provide direction for further study, including timing of tacrolimus conversion and interaction with other therapies.
Presence of Gal‐α1,3Gal epitope on xenogeneic lines: implications for cellular gene therapy based on the encapsulation technology
Authors: Déglon Nicole , Aubert Vincent , Spertini François , Winkel Laurence , Aebischer Patrick
Published: November 2004

Déglon N, Aubert V, Spertini F, Winkel L, Aebischer P. Presence of Gal‐α1,3Gal epitope on xenogeneic lines: implications for cellular gene therapy based on the encapsulation technology. Xenotransplantation 2003; 10: 204–213. © Blackwell Munksgaard, 2003

Exposure to human serum induces the lysis of xenogeneic cells through natural antibodies and complement activation. The carbohydrate Galactose‐α1,3‐Galactose (Gal‐α1,3‐Gal) epitope, has been shown to be the principal antigenic determinant on target cells. This reaction is, therefore, particularly important for xenogeneic cell‐based therapy. As a first step toward the evaluation of the impact of this phenomenon for encapsulated xenogeneic cells, we have evaluated the presence of the Gal‐α1,3Gal epitope on two cell lines currently being used for the systemic delivery of protein in the periphery or the treatment of neurodegenerative diseases. In the second part of the study, we have tested and compared human serum and cerebrospinal fluid (CSF) for the presence of xenoreactive natural antibodies (XNAs) and their potential impact on the survival of xenogeneic cells. Fluorescence‐activated cell sorting analysis indicated that baby hamster kidney (BHK) cells expressed low levels of the α‐Gal epitope, whereas mouse myoblast C2C12 cells were extensively stained with the specific IB4‐lectin. There was a direct correlation between serum killing and the level of Gal‐α1,3‐Gal epitope expression on these cells. Importantly, we showed that CSF did not lyse BHK and C2C12 cells as determined by cytotoxic crossmatch assays. The reaction was specific as the addition of soluble Gal‐α1,3‐Gal sugar to human serum effectively reduced cell killing, and the overproduction of α‐1,3‐galactosyltransferase in BHK cells significantly increased inactivation by human serum. To interfere with this antibody–antigen reaction and develop cell lines particularly suitable for cell‐based therapy, we either selected C2C12 clones expressing low levels of Gal‐α1,3‐Gal or high levels of α‐1,2‐fucosyltransferase. These cells were found to be resistant to complement‐mediated cytolysis. These strategies may, therefore, protect encapsulated xenogeneic cells transplanted in the periphery or the central nervous system even in an unlikely event of a blood–brain barrier breakage and the post‐transplantation development of an antibody response.
Effect of plasma exchange in combination with deoxyspergualin on the survival of guinea‐pig hearts in macrophage‐depleted C6‐deficient rats
Authors: Wu Guosheng , Korsgren Olle , Sun Shibo , Van Rooijen Nico , Tibell Annika
Published: November 2004

Abstract: The present study aimed to evaluate the effect of plasma exchange (PE) in combination with certain immunosuppressive agents on the survival of guinea‐pig hearts in C6‐deficient (C6–) rats. To deplete macrophages, we gave liposome‐encapsulated dichloromethylene diphosphonate (Lip‐Cl2MDP) intravenously (i.v.) in a dose of 10 mg/kg on day 2 before transplantation and every 5 days until rejection. Deoxyspergualin (DSG) was also given i.v. in a dose of 10 mg/kg/day from day −2 until rejection. Plasma exchange was performed 1 day before xenografting. All animals were splenectomized just before heart transplantation. Heart xenografts were evaluated twice daily and harvested at the time of rejection. The serum levels of anti‐guinea‐pig xenoreactive antibody (IgM, IgG) were measured using enzyme‐linked immunosorbent assay (ELISA). Graft survival was 2.8 ± 0.5 days in control rats, and 4.0 ± 0.3 days with PE alone. A combination of PE with Lip‐Cl2MDP or DSG did not improve the results (4.2 ± 0.6 days vs. 4.8 ± 0.6 days, respectively). While in rats treated with PE and the combination of Lip‐Cl2MDP and DSG, graft survival was significantly prolonged (6.9 ± 1.1 days, P < 0.01 vs. controls). In untreated control rats, xenoreactive antibody (IgM, IgG) levels decreased immediately after PE, but their levels rapidly returned to normal. In rats treated with DSG or DSG + Lip‐Cl2MDP, the IgM levels remained low during the observation period. Immunohistochemistry showed that macrophage infiltration into the graft was suppressed in Lip‐Cl2MDP‐treated groups at the time of rejection. Our results demonstrate that sustained suppression of antibody levels can be achieved by PE in combination with DSG and xenograft survival is further prolonged in macrophage‐depleted C6– rats. These findings suggest that strategies targeting antibody and macrophages may be useful in prolonging xenograft survival.
Xenogeneic skin graft rejection in M‐CSF/macrophage deficient osteopetrotic mice
Authors: Zhao Yong , Xiong Wanfen , Yang Tianyu , Prall Amy , Baxter B. T. , Langnas Alan N.
Published: November 2004

Zhao Y, Xiong W, Yang T, Prall A, Baxter BT, Langnas AN. Xenogeneic skin graft rejection in M‐CSF/macrophage deficient osteopetrotic mice. Xenotransplantation 2003; 10: 232–239. © Blackwell Munksgaard, 2003

Background: The cellular infiltrate in xenografts suggests that macrophages may be involved in xenograft rejection. However, the precise role of macrophages in xenograft rejection has not yet been fully addressed.

Methods: Xenogeneic rat skin grafts were transplanted to macrophage colony stimulating factor (M‐CSF)/macrophage‐deficient osteopetrotic ([OP]–/–) and wild‐type control mice. Skin graft survival and antidonor rat humoral responses were quantified.

Results: Xenogeneic rat skin grafts survived 13 days in wild‐type control mice, survival of rat skin grafts was significantly prolonged to 24 days in [OP]–/– mice (P<0.01). Similar results were observed in sensitized [OP]–/– and control mouse recipients, showing markedly prolonged rat skin graft survival in [OP]–/– mice. Levels of T‐cell‐dependent antirat antibodies [immunoglobulin G (IgG)2a and IgG3] in sera of [OP]–/– mice were significantly lower than that of control mice 2 weeks post‐rat skin grafting. The proliferative responses to xenogeneic rats not to allogeneic mouse stimulation of T cells from [OP]–/– mice were significantly lower than that of wild‐type mice. However, neutrilization of M‐CSF by anti‐M‐CSF monoclonal antibody (mAb) or the addition of M‐CSF to the in vitro culture systems of wild‐type or [OP]–/– mouse T‐responder cells, respectively, did not significantly change proliferative responses and cytolytic function against xenogeneic rat targets of wild‐type or [OP]–/– mouse T‐responder cells.

Conclusions: The in vitro data indicate that M‐CSF does not directly regulate cellular immune responses to xenoantigens. The present studies indicate that macrophages may play an important role in immune rejection of xenografts. The precise role of macrophages in xenograft rejection should be further investigated.
Hypodermin A, a new inhibitor of human complement for the prevention of xenogeneic hyperacute rejection
Authors: Malassagne B. , Regimbeau J. M. , Taboit F. , Troalen F. , Chéreau C. , Moiré N. , Attal J. , Batteux F. , Conti F. , Calmus Y. , Houssin D. , Boulard C. , Houdebine L. M. , Weill B.
Published: November 2004

Abstract: Background: Hyperacute rejection (HAR) of discordant xenografts in the pig‐to‐human combination can be prevented using tranplants expressing transgenic molecules that inhibit human complement. Hypodermin A (HA), a serine esterase that degrades C3, was tested in the guinea‐pig‐to‐rat and in the pig‐to‐human combinations.

Methods: Hypodermin A was tested in vitro, ex vivo, and in vivo models of HAR in the guinea‐pig‐to‐rat combination. Hamster ovary cells (CHO) and a line of porcine aortic endothelial cells (PAEC11) were transfected with HA complementary DNA (cDNA).

Results: The pattern of degradation of rat and human C3 by HA was different (multiple bands lower than 40 kDa) from the physiologic pattern observed after spontaneous degradation of rat C3 or physiologic activation of human C3. The CH50 activity in serum was significantly lower in rats treated with 3.2 mg HA/kg than in untreated rats (45 ± 16 U/ml vs. 700 ± 63 U/ml, P < 0.05). Sera from rats injected with 3.2 mg/kg of HA were less effective in lysing guinea‐pig endothelial cells (12 ± 7%) than normal rat sera (79 ± 3%; P < 0.001). Ex vivo, guinea‐pig hearts perfused by rat serum supplemented with HA survived longer than those perfused by non‐treated serum (210 ± 34 and 154 ± 71 min, respectively; P < 0.05). In vivo, guinea‐pig hearts transplanted into HA treated rats survived longer than in non‐treated rats (27 ± 5 min vs. 13 ± 4 min; P < 0.001). In the presence of human serum, smaller amounts of C6 and C5b‐9 were deposited onto HA‐transfected CHO cells than onto control cells. The mHA‐PAEC11 cells were significantly more resistant to lysis by human C than control PAEC11 cells.

Conclusions: These data suggest that transgenic HA could be used to prevent hyperacute xenogeneic rejection.
Foraging location and range of White‐chinned Petrels Procellaria aequinoctialis breeding in the South Atlantic
Authors: Berrow Simon D. , Wood Andrew G. , Prince Peter A.
Published: November 2004

The foraging range and principal feeding areas of White‐chinned Petrels breeding at South Georgia were determined using satellite telemetry. Foraging trips during incubation lasted 12–15 days and covered 3000–8000 km and 2–11 days and 1100–5900 km during chick‐rearing. Adults covered less distance per day during chick‐rearing (71 km) than during incubation (91 km) but the proportion covered at night (47%) was the same. Mean (31–34 km/h) and maximum (80 km/h) flight velocities were similar during both periods of the breeding season and during day and night. Between incubation shifts, White‐chinned Petrels travelled to the Patagonian shelf; during chick‐rearing they foraged more extensively. Most locations were between 30° to 55°W and 52° to 60°W around South Georgia/Shag Rocks and south to the South Orkney Islands. Diet samples from known foraging locations suggested birds fed mainly on krill and squid. They caught the squid Brachioteuthis? picta and Galiteuthis
glacialis around Shag Rocks/South Georgia and also at sites close to
the South Orkney Islands; Illex argentinus on the Patagonian shelf. Dispersal of adults after breeding failure was south to the South Orkney Islands then west to the Falkland Islands. This study confirms that breeding White‐chinned Petrels are amongst the widest‐ranging of seabirds; they may minimise competition with other Procellariiformes in the South Atlantic by their more extensive foraging range. The nature and extent of their range also brings substantial risk of high mortality rate in South Atlantic long‐line fisheries.
Producing extra eggs does not deplete macronutrient reserves in European Starlings Sturnus vulgaris
Authors: Christians Julian K.
Published: November 2004

Recent studies have suggested that the size of avian clutches may be determined in part by the costs of egg production, which are thought to involve the depletion of endogenous nutrient reserves. I tested the hypothesis that producing extra eggs would deplete protein and lipid reserves in a passerine species, the European Starling Sturnus
vulgaris. The first three eggs of clutches were removed on the days they were laid to induce females to lay extra eggs. Females responded to this manipulation by laying, on average, 1.3 eggs more than controls. However, based on the distribution of clutch sizes, it appears that some females responded to the removal of three eggs by producing more than one extra egg, whereas others responded by laying no extra eggs or by deserting. In unmanipulated females, the lean dry mass of the flight muscles and total body lipid were found to decline throughout breeding, an observation which is often interpreted as evidence that egg production depletes endogenous reserves. However, females experimentally induced to produce an extra egg did not have reduced stores of protein or lipid at clutch completion. No effect was observed in starlings even though this study had substantial (80%) power to detect a change in protein reserves of the same magnitude as that observed in a previous study of gulls. The decrease in flight muscle mass that has frequently been observed during breeding in passerines may not be due simply to mobilization of endogenous protein reserves.
The scaling and selection of sexually dimorphic characters: an example using the Marbled Teal
Authors: Green Andy J.
Published: November 2004

Current theory and empirical evidence suggests that, if a character is sexually dimorphic as a result of sexual selection, it should be positively allometric (i.e. relatively larger in larger individuals), whereas if the dimorphism is the result of natural selection (e.g. niche divergence), it should be isometric. I show how this can be used to study the selective forces responsible for dimorphic morphological characters, using the monochromatic Marbled Teal Marmaronetta angustirostris as an example. In absolute terms, first‐year male teals have a higher body mass, wing length, head length and bill length than females. In relative terms (controlling for body size), males still have longer wings, heads and bills. The scaling in Marbled Teal suggests that bill and head dimorphisms are due to sexual selection, whereas wing dimorphism is due to natural selection. Tail length is sexually monomorphic but positively allometric, possibly because of a display function. Such scaling studies are easy to carry out, and provide a useful complement to direct investigation of the influence of variation in the size of dimorphic characters on mating success, foraging efficiency etc.
Attraction of Hoopoe Upupa epops females and males by means of song playback in the field: influence of strophe length
Authors: Martín‐Vivaldi Manuel , Palomino José Javier , Soler Manuel
Published: November 2004

Experimental Hoopoe Upupa epops songs prepared with synthetic sound to differ in strophe length were used to test whether Hoopoe females prefer long strophes. The songs were broadcast simultaneously in the field from two loudspeakers situated 100 m apart, in early spring, when females actively search for mates. The playbacks attracted a total of 87 individuals, both males and females, with a maximum of five individuals (three males and two females) per trial. A female was considered to have been attracted by the song broadcast from a loudspeaker when she approached unaccompanied by a male, and when there was no male nearby. A total of 15 females chose one of the songs and significantly more were attracted by the one with long strophes. These results suggest that in the Hoopoe, male song attracts females, and that strophe length is a sexually selected song cue. There were no differences in the number or kind of males (classified according to strophe length) attracted by each playback. Frequently the experiment attracted more than one male simultaneously. These aggregations cannot be explained as territorial responses, and their significance is discussed together with that of natural spontaneous groupings of displaying males. Apparently males aggregate where they expect to find females.
Predation risk and moonlight avoidance in nocturnal seabirds
Authors: Mougeot François , Bretagnolle Vincent
Published: November 2004

Unlike most seabird families, the vast majority of small petrel species are nocturnal on their breeding grounds. Further, they reduce markedly their activity when the light level increases. Moonlight avoidance might be a consequence of reduction in foraging profitability, as bioluminescent prey do not come to the sea surface on bright nights. Alternatively, petrels may avoid colonies during moonlit nights because of increased predation risk. We studied predation on petrels by Brown Skuas Catharacta antarctica lönnbergi at Kerguelen, and the
influence of moonlight on behaviour of both skuas and petrels, to test
the ‘predation risk’ hypothesis. On the study area, Brown
Skuas hunt at night and prey heavily upon the Blue Petrel Halobaena
caerulea and the Thin‐billed Prion Pachyptila belcheri. Predation risk was higher on moonlit nights, as skuas caught more prey, and particularly more Blue Petrels when the light level increased. Nightly intakes of Blue Petrel and Thin‐billed Prion by skuas was related to colony attendance of non‐breeders rather than that of breeders. Biometry of prey also suggested that skuas caught a higher proportion of non‐breeding birds than was present at the colonies. Predation risk was thus greater in non‐breeders and on moonlit nights. Colony attendance by non‐breeding Blue Petrels and Thin‐billed Prions was also reduced during moonlit nights. Vocal activity, which is mainly by non‐breeders, was also drastically reduced when the light level increased in the species suffering the highest predation rate. Our results supported the ‘predation risk’ hypothesis, although the ‘foraging efficiency’ and the ‘predation risk’ hypotheses are not mutually exclusive: the former might explain the moonlight avoidance behaviour of breeding, and the latter that of non‐breeding individuals.
Intraspecific variation in size and density of Avocet colonies: effects of nest‐distances on hatching and breeding success
Authors: Hötker Hermann
Published: November 2004

In many colonial bird species there is considerable intraspecific variation in colony size and inter‐nest distance (colony density). Possible causes of this variation and its effects on hatching success (survival of eggs) and breeding success (probability of a pair raising chicks) were studied in 48 Avocet Recurvirostra avosetta colonies in Schleswig‐Holstein (Germany) between 1991 and 1996. Colony density was influenced by time of year and habitat (categories: island or mainland, close to or far from feeding grounds). Colonies on islands had the highest densities. When all available space at a colony site was used, colonies became very dense (mean nearest‐neighbour nest distance less than 1 m). Colony size (number of clutches) was influenced by time of year, but not by habitat. Hatching success was low in high density colonies and in very low density ‘colonies’ (single nests) and high over a broad range of intermediate nest densities. The low success rate of single nests was caused by a very high predation rate, whereas the low success rate in very dense colonies was caused by a high rate of nest abandonment. Nest abandonment in very dense colonies was associated with a high level of aggressiveness among Avocets during the egg‐laying period. Due to territorial behaviour, Avocets seemed to be expelled from the densest breeding sites. In very dense colonies, high frequencies of clutches of unusual size occurred due to conspecific nest parasitism. The number of Avocets taking part in attacks on potential egg predators was small and (in colonies of more than one clutch) depended neither on colony size nor on colony density. Despite a low hatching success in very dense colonies, individuals breeding in the densest colonies had significantly better chances of raising chicks than Avocets breeding in less dense colonies. Coloniality seemed to be obligatory for Avocets in order to ensure hatching success. The size and density of colonies seemed to be associated with the availability of suitable nesting habitats (islands).
Estimation of calcium intake by Meadow Pipit nestlings in an acidified area
Authors: Bureš S. , Weidinger K.
Published: November 2004

Calcium availability might limit reproductive output in birds either by effects on eggshell formation or on skeletal growth of nestlings. Quantitative data on calcium intake by nestlings of free‐living passerines are needed to test the second hypothesis. In an acidified area of the Jeseníky Mountains (Czech Republic), estimates were made of calcium requirements and intake in Meadow Pipit Anthus pratensis
nestlings during the nestling period. Analyses of nestling diet,
determined by neck ligatures, showed that only snail shells were an
important source of calcium. During the whole nestling period dry matter
intake per nestling was 31.1 g, of which snail shells contributed 0.626
g. The total calcium necessary for successful development of each
nestling was estimated as 139.8 mg. Arthropods in the diet provided only
16% of the calcium requirement. However, sufficient calcium was ensured
by intake of snails (mainly Arianta arbustorum), despite their low abundance in the area.
Orthodontically stressed periodontium of transgenic mouse as a model for studying mechanical response in bone: The effect on the number of osteoblasts
Authors: Pavlin Dubravko , Goldman Eric S. , Gluhak‐Heinrich Jelica , Magness Marla , Zadro Renata
Published: November 2004

A better understanding of cellular and molecular mechanisms involved in response to mechanical stress is a prerequisite for future improvements in orthodontic treatment. To expand the application of molecular biology techniques in this area of research, we developed and characterized a mouse tooth movement model. The aim of this study was to biomechanically characterize this model and to evaluate the effect of orthodontic stress on the proliferation of periodontal osteoblasts. We used an orthodontic coil spring appliance with a low force/deflection rate, which produced an average force of 10–12 g. This design provided a predictable tipping movement of the molar with the center of rotation at the level of root apices. Histological observations of paradental tissues revealed a response favoring a fast onset of tooth movement and deposition of new osteoid starting after 3 days of treatment. The effect of treatment on the histomorpometric parameter of the number of osteoclasts per unit bone perimeter was determined after 1, 2, 3, 4, 6, and 12 days of treatment. Starting with day 2, the osteoblast number showed a modest but consistent increase in treated periodontal sites at all time‐points, ranging from 14 to 39% and becoming significant only at day 6. Only a moderate increase in the number of osteoblasts in the areas of otherwise intense bone matrix synthesis suggests that, during bone formation, proliferation of cells has a smaller role compared to a marked increase in differentiation of individual cells. The mouse model, which allows for a controlled, reproducible, orthodontic mechanical loading, can be applied to both wild‐type and transgenic animals and should enhance the research of the transduction of mechanical orthodontic signal into a biological response.
Craniofacial computed tomography scanning: technology, applications and future trends
Authors: Vannier MW
Published: November 2004

Structured Abstract

Author –
Vannier MW

Objectives – Craniofacial imaging in three dimensions depends on computed tomography (CT) and related technologies. This paper explains the state‐of‐the‐art for medical and dedicated craniofacial cone‐beam CT scanners.

Method – Current medical CT scanners are surveyed, especially the recently announced 16 simultaneous slice models with subsecond source–detector rotation times and spiral/helical third generation geometry. The medical scanner technology is contrasted with dedicated low‐cost craniofacial cone‐beam CT scanners to delineate the relevant technologies and clarify the differences.

Results – CT scanners performance in any task is determined by their detectors and reconstruction algorithm primarily and to a lesser extent by the X‐ray source, dose utilization, computational and display electronics, and software for post‐processing. Each of these components differs between medical and low‐cost cone‐beam scanners, and the differences are tabulated and explained.

Conclusion – Low‐cost craniofacial CT scanners are significantly different from general purpose medical CT scanners, with compromises in technical performance. Despite their limitations, these instruments are remarkably useful for their intended application domain and should improve as computers continue to increase their performance.
Dynamic stereometry of the temporomandibular joint
Authors: Palla S , Gallo LM , Gössi D
Published: November 2004

Authors
– Palla S, Gallo LM, Gössi D

Studies on jaw kinematics have provided a good understanding of the motion of the mandible in space, but are of little biomechanical relevance because they could not relate the movements to anatomic structures. This is possible by the combination of three‐dimensional reconstructions of the temporomandibular joint (TMJ) anatomy with jaw motion recordings. This technique allows us to analyze the variation of the relationship between the articular surfaces, providing indirect insight into disk deformation during function and parafunction as well as TMJ loading.

As far as the variation of the condyle–fossa distance is concerned, data indicated that during chewing the distance was smaller 1) on closing than on opening; 2) on the balancing than on the working side; and 3) during chewing of hard than soft food. Moreover, during a forceful static biting, the condyle–fossa distance decreased more on the contralateral, i.e. on the balancing side than on the working side. The decrease was related to the degree of clenching force. These results support the content that both condyles are loaded during chewing and the balancing side joint more than the working one.

Biomechanically, the development of osteoarthrosis is more likely related to the magnitude and frequency of stresses applied on the cartilage. Joint movements produce tractional forces that may cause shear stresses contributing to cartilage wear and fatigue. Tractional forces are the result of frictional forces caused by the cartilage surface rubbing and of plowing forces caused by the translation of a stress‐field through the cartilage matrix, as the intra‐articular space changes during motion. Translation of the stress‐field in mediolateral direction seems to be particularly important for the integrity of the TMJ disk because of its anisotropic properties. Dynamic stereometry showed that stress‐fields translate in mediolateral direction during opening/closing, protrusion and laterotrusion, and that their translatory velocity varies intraindividually and with the rate of the condylar movement. Furthermore, the results seem to indicate that the lateral area of the TMJ disk is more often exposed to shear stresses caused by stress‐field translation than the medial one.

In conclusion, dynamic stereometry provides a good visualization of the movement of the condyles in the respective fossae. This helps improving our understanding for the complexity of condylar movements. The technique may also contribute to ameliorate our knowledge of TMJ biomechanics and therefore of the etiology of degenerative joint diseases and possibly also of internal derangement.
Development of the dentition: four‐dimensional visualization and open questions concerning the morphogenesis of tooth form and occlusion
Authors: Radlanski RJ
Published: November 2004

Structured Abstract

Author

– Radlanski RJ

Objectives – The formation of the dental primordial should be visualized with special reference to characteristic differences for each single primordium. Until today, it has not been clear how traffic of the ameloblasts is controlled, how the folding pattern of the occlusal relief is generated or how the enamel production is terminated at the enamel surface.

Design – Using computer‐aided reconstructions from histological serial sections, the dental primordial were visualized and, using fractured enamel specimens, the traces of each single ameloblast were followed by means of scanning electron microscopy. In this way, the developmental movements of the inner enamel epithelium can be reconstructed.

Results – Gathering morphological knowledge, three‐dimensional polygon sets of shape data were input into a computer workstation and animated by means of the software Soft Image (Microsoft).

Conclusions – The development of the human primary and permanent dentition was animated to simulate growth.
Prenatal craniofacial morphogenesis: four‐dimensional visualization of morphogenetic processes
Authors: Radlanski RJ
Published: November 2004

Structured Abstract

Author –
Radlanski RJ

Objectives – Basic research concerning craniofacial development presently runs along two pathways, namely the molecular and the morphometric. This gap needs to be bridged.

Design – Using histological serial sections of human fetuses computer‐aided three‐dimensional reconstructions were made (Software Analysis, SIS) with special focus given to all anatomical structures of the orofacial region of the growing head.

Results – All reconstructions can be viewed from any rotation and they are available for virtual dissection according to anatomical rules. As an example, the prenatal development of the human mandible with the formation of the mental foramen therein is described. Furthermore, the spatial arrangement of bone, cartilage and nerves is presented in three dimensions in different developmental stages. The interaction of tissues with possible morphogenetic interaction is discussed.

Conclusions – This work serves as a reference system for prenatal development in comparison with pathological development.
Validation of Align Technology's Treat IIITM digital model superimposition tool and its case application
Authors: Miller RJ , Kuo E , Choi W
Published: November 2004

Structured Abstract

Authors – Miller RJ, Kuo E, Choi W

Objective – An assessment of the efficacy and accuracy of three‐dimensional computer‐based predictive orthodontic systems requires that new methods of treatment analysis be developed and validated.

Design – Invisalign® is a digitally fabricated, removable orthodontic appliance that has been commercially available since 1999. It is made up of two main components: 1) computerized graphical images of a patient's teeth moving through a series of stages from initial to final position; 2) pressure formed clear plastic appliances made from stereolithography models of the images in the first component.

Setting and sample population – The manufacturer of Invisalign (Align Technology, Inc.) has created a software tool that can be used to superimpose digital models to evaluate treatment outcomes in three dimensions. Using this software, research was conducted to determine if a single operator could repeatedly superimpose two identical digital models using 12 selected points from the palatal rugae over 10 trials. The tool was then applied to one subject's orthodontic treatment.

Experiment variables – The output from this tool includes rotations, translations and morphological changes. For this study, translations and rotations were chosen.

Results – The results showed that the digital superimposition was reproducible, and that after multiple trials, the superimposition error decreased. The average error in x, y, z, Rx, Ry and Rz after 10 trials was determined to approach approximately 0.2 mm in translation and less than 1° in rotation, with a standard deviation of 0.15 mm and 0.7 mm, respectively. The treatment outcome from a single Invisalign‐treated bicuspid extraction case was also evaluated tooth‐by‐tooth in x, y, z, Rx, Ry and Rz dimensions.

Conclusion – Using the palate, as a stable reference seemed to work well and the evaluation of the single case showed that many, but not all, of the planned movements occurred.
Development of dento‐maxillofacial cone beam X‐ray computed tomography system
Authors: Yamamoto K , Ueno K , Seo K , Shinohara D
Published: November 2004

Authors– Yamamoto K, Ueno K, Seo K, Shinohara D

We have developed a cone beam X‐ray computed tomography (CT) system to make more accurate three‐dimensional (3‐D) images for diagnosis of dento‐maxillofacial region. The developed system has sufficient spatial resolution, resolution of 3‐D images and image distortion for diagnosis of dento‐maxillofacial region.
The impact of medical technology on office workflow
Authors: McEvoy SP
Published: November 2004

Author– McEvoy SP

Digital technologies are gaining wider acceptance within the medical and dental professions. The lure of increased productivity and improved quality entice practices to adapt. These systems are beginning to have a profound impact on the workflows within the practice, as well as putting new demands on existing resources. To successfully implement a new technology within your practice, you must look beyond advertising and discover the real requirements of the system. Vendors rarely try to help beyond the sale and installation of their equipment, nor do they consider how their product might require you to modify the way you and your staff work. Acquiring the necessary knowledge through self‐education, a consultant, or (preferably) a combination of the two is the best way to integrate a new technology with your practice.
Cone beam computed tomography in craniofacial imaging
Authors: Sukovic P
Published: November 2004

Author– Sukovic P

Cone beam computed tomography (CT) has the potential to reduce the size and cost of CT scanners. Because this emerging technology produces images with isotropic submillimeter spatial resolution, it is ideally suited for dedicated dentomaxillofacial CT scanning. When combined with application‐specific software tools, cone beam computed tomography can provide dentomaxillofacial practitioners with a complete solution for performing specific diagnostic and surgical tasks, such as dental implant planning. In this paper, we provide a brief overview of cone beam scanning technology and compare it with the fan beam scanning used in conventional CT scanners. We introduce ‘DentoCATTM’, a relatively small, low‐cost cone beam CT scanner dedicated for dentomaxillofacial imaging developed at Xoran Technologies. We present images generated by the DentoCATTM scanner and provide an assessment of its performance in terms of spatial resolution and effective radiation dose. Finally, we illustrate the clinical utility of the scanner by presenting the results we have obtained to date using the DentoCATTM scanner in conjunction with an implant planning software tool.
Extramural clinic in comprehensive care education
Authors: Petersson K. , Nilner M. , Rohlin M.
Published: November 2004

In the Malmo model, the students' experience of their future professional context is a basic principle. Therefore, comprehensive care education includes one day per week in the public dental health service during the 9th and 10th semesters. There are three main objectives of this clinical module that the students should be able to, namely:

Further develop insights in general dentistry and its pre‐requisites in Sweden.

Identify themselves as a member of the professional team.

‘Think like a dentist’.

A questionnaire was given to final year students and their clinical supervisors in the public dental health service. The students were asked to self‐assess to which extent they had achieved the objectives and to list the most valuable experiences of their practice. The supervisors assessed the students' fulfilment of the objectives and were asked on their experience of the co‐operation with the dental school and their perception of the students' clinical competence. On a 9‐grade rating scale both students and supervisors rated the fulfilment of the objectives high (7–9). The supervisors rated somewhat higher than the students did. The students mentioned that it was most valuable to take full responsibility, work closely together with a dental assistant and to experience a ‘real’ professional context. The supervisors' most frequent comment was that the co‐operation with the faculty could be improved considerably.

Our conclusion is that both the dental students and their clinical supervisors considered this model for extramural clinical training most valuable.
Clinical findings and magnetic resonance imaging in severe cyclosporine‐related neurotoxicity after allogeneic bone marrow transplantation
Authors: Trullemans Fabienne , Grignard Ferre , Van Camp Benjamin , Schots Rik
Published: November 2004

Abstract: Objectives: Severe neurotoxicity is a recognized complication of cyclosporin A (cyclosporine, CSA). Neuroimaging studies typically show reversible brain lesions, predominantly confined to the white matter. Our aim was to delineate clinical characteristics and to specify results of magnetic resonance imaging (MRI) and computerised tomography (CT) scan findings. Methods: Cases of severe cyclosporine‐related neurotoxicity (SNCT) were identified among a series of 129 consecutive allogeneic transplant recipients. Clinical features were analysed, including CSA levels, electrolytes, cholesterolemia and magnesemia. MRI and/or CT scans were obtained within 24 h to 4 d after the onset of neurotoxicity. Results: Six patients (4.6%) developed a prodromal phase (headache and/or hypertension), followed by SCNT, including generalized seizures (n = 5), occipital blindness (n = 1) and hemiparesis (n = 1). There was no correlation between the laboratory findings and the onset of SNCT. All patients were on corticosteroid treatment. MRI studies showed hyperintensity lesions, predominantly in the posterior cerebrum, with both subcortical and cortical involvement in 4 out of 5 patients. Cerebellar involvement (n = 4) was also a frequent finding. The signal abnormalities, corresponding to the anastomotic border zones between major cerebral and cerebellar arteries, were limited to the respective cortical areas. Conclusion: Association of corticosteroids is a trigger in the development of SCNT. MRI is recommended for the early identification of the transient brain lesions in patients with a prodromal phase. The more specific distribution of the lesions in the anastomotic border zones suggests vascular injury as a contributing factor in the pathology of SNCT.
Increased cell surface expression of C‐terminal truncated erythropoietin receptors in polycythemia
Authors: Motohashi Tsutomu , Nakamura Yukio , Osawa Mitsujiro , Hiroyama Takashi , Iwama Atsushi , Shibuya Akira , Nakauchi Hiromitsu
Published: November 2004

Abstract: Primary familial and congenital polycythemia (PFCP) is a disorder characterized by an increased number of erythrocytes despite normal blood oxygen pressure and a normal serum erythropoietin (EPO) level. Recent studies revealed that erythroid progenitor cells from certain individuals with PFCP express various forms of EPO receptor (EPOR) truncated at the terminal carboxyl site (EPOR‐TTC(PFCP)). EPOR‐TTC(PFCP) can transmit EPO‐mediated proliferative signals more efficiently than can full‐length EPOR (EPOR‐F), at least partly because of defective recruitment of SHP‐1 phosphatase to these receptors. In agreement with previous studies, Ba/F3 transfectants expressing EPOR‐TTC(PFCP) showed higher proliferative responses to EPO. In those transfectants, we found that EPOR‐TTC(PFCP) was expressed more abundantly on the cell surface than was EPOR‐F. This tendency was confirmed by a transient‐expression experiment using COS7 cells. Since expression levels of EPOR protein were not significantly different among these transfectants, differences in cell surface expression were likely dependent on post‐translational mechanism(s). In addition to defective recruitment of SHP‐1 to EPOR‐TTC(PFCP), more efficient transport and expression on the cell surface appear to serve as mechanisms responsible for increased EPO‐responsiveness of erythroid progenitor cells in PFCP.