bluuebunny/crossref_metadata_2025_split huggingface dataset:
Function, structure and therapeutic potential of complement C5a receptors
Authors: Monk P N , Scola A‐M , Madala P , Fairlie D P 
Published: July 2007

Complement fragment (C)5a is a 74 residue pro‐inflammatory polypeptide produced during activation of the complement cascade of serum proteins in response to foreign surfaces such as microorganisms and tissue damaged by physical or chemical injury. C5a binds to at least two seven‐transmembrane domain receptors, C5aR (C5R1, CD88) and C5L2 (gpr77), expressed ubiquitously on a wide variety of cells but particularly on the surface of immune cells like macrophages, neutrophils and T cells. C5aR is a classical G protein‐coupled receptor that signals through Gαi and Gα16, whereas C5L2 does not appear to couple to G proteins and has no known signalling activity. Although C5a was first described as an anaphylatoxin and later as a leukocyte chemoattractant, the widespread expression of C5aR suggested more general functionality. Our understanding of the physiology of C5a has improved significantly in recent years through exploitation of receptor knockout and knockin mice, C5 and C5a antibodies, soluble recombinant C5a and C5a analogues and newly developed receptor antagonists. C5a is now also implicated in non‐immunological functions associated with developmental biology, CNS development and neurodegeneration, tissue regeneration, and haematopoiesis. Combined receptor mutagenesis, molecular modelling, structure‐activity relationship studies and species dependence for ligand potency on C5aR have been helpful for identifying ligand binding sites on the receptor and for defining mechanisms of receptor activation and inactivation. This review will highlight major developments in C5a receptor research that support C5aR as an important therapeutic target. The intriguing possibilities raised by the existence of a non‐signalling C5a receptor are also discussed.British Journal of Pharmacology (2007) 152, 429–448; doi:10.1038/sj.bjp.0707332; published online 2 July 2007
A functional comparison of recombinant and native somatostatin sst2 receptor variants in epithelia
Authors: Holliday N D , Tough I R , Cox H M 
Published: July 2007

Background and purpose.Somatostatin (SRIF‐14) exerts broad spectrum antisecretory effects by activating the somatostatin 2 (sst2) receptor. The rat (r) sst2 receptor exists in ‘long’ (sst2a) and ‘short’ (sst2b) forms that differ in their C termini, while a single human (h) sst2a exists. This study compares the characteristics of recombinant rsst2a, rsst2b and hsst2a activation in human epithelia, and with native sst2 responses in rat colon.Experimental approach.Epithelial layers of each clone or rat colon were placed in Ussing chambers and short‐circuit current (ISC) measured in response to SRIF‐14 and chosen analogues. The relative potencies and ability to cause desensitization to SRIF‐14 were assessed, and the affinities of the sst2 antagonist, D‐Tyr8 CYN154806 for hsst2a, rsst2a and native rat colon sst2 receptors were established.Key results.Basolateral SRIF‐14 responses were transient in hsst2a and rsst2a epithelia, but prolonged in rsst2b‐expressing cells. Activation of rsst2a resulted in significant desensitization to SRIF‐14 and receptor phosphorylation, whereas the rsst2b receptor did neither. Sst2‐preferred agonists (BIM23190C and BIM23027) reduced Isc with similar potency and both caused complete desensitization to SRIF‐14. CYN154806 antagonized hsst2a and rsst2a receptors with pKB values of 7.9 and 7.8, respectively. In rat colon mucosa, CYN154806 blocked SRIF‐14 responses with a pA2 value of 8.2, and BIM23190C responses with a pKB of 8.4.Conclusions and implications.SRIF‐14 caused rapid rsst2a receptor phosphorylation and desensitization of epithelial antisecretory responses, neither of which occurred with the rsst2b receptor. These mechanisms are most likely to be a prerequisite for sensitivity to sst2‐analogues with radiotherapeutic potential.British Journal of Pharmacology (2007) 152, 132–140; doi:10.1038/sj.bjp.0707365
Heart rate variability measures: a fresh look at reliability
Authors: Pinna Gian Domenico , Maestri Roberto , Torunski Antoni , Danilowicz-Szymanowicz Ludmila , Szwoch Malgorzata , La Rovere Maria Teresa , Raczak Grzegorz 
Published: July 2007

Despite its extensive use in physiological and clinical research, the analysis of HRV (heart rate variability) is still poorly supported by rigorous reliability studies. The main aim of the present study was to perform an in-depth assessment of absolute and relative reliability of standard indexes of HRV from short-term laboratory recordings. In 39 healthy subjects [mean age (min–max): 38 (26–56) years; 18 men and 21 women] we recorded 5 min of supine ECG during spontaneous and paced (15 breaths/min) breathing. The test was repeated on the next day under the same conditions. From the RR intervals we computed standard indexes of HRV: SDNN (S.D. of RR interval values), RMSSD (root-mean-square of successive RR interval differences), LF (low frequency) and HF (high frequency) power (absolute and normalized units) and LF/HF. Absolute reliability was assessed by 95% limits of random variation; relative reliability was assessed by the ICC (intraclass correlation coefficient). The sample size needed to detect a mean difference ≥30% of the between-subject S.D. was also estimated. Although there was no significant mean change between the two tests, we found that in individual subjects the second measurement was as high/low as 1.9/0.5 times (SDNN, best case) and 3.5/0.3 times (LF/HF, worst case) the first measurement, due to pure random variation. For most parameters the ICC was &gt;0.8 (range 0.65–0.88). The estimated sample size ranged from 24–98 subjects. Reliability indexes tended to improve during paced breathing. We conclude that short-term HRV parameters are subject to large day-to-day random variations. Random error, however, represents a limited part of the between-subject variability; therefore observed differences between individuals mostly reflect differences in the subjects' error-free value rather than random error. Overall, paced breathing improves reliability.
Expression and extracellular release of Trx80, the truncated form of thioredoxin, by TNF-α- and IL-1β-stimulated human synoviocytes from patients with rheumatoid arthritis
Authors: Lemarechal Hervé , Anract Phillippe , Beaudeux Jean-Louis , Bonnefont-Rousselot Dominique , Ekindjian Ohvanesse G. , Borderie Didier 
Published: July 2007

Thioredoxin (Trx) plays several important roles, through changes to sulfhydryl reactions and protein interactions, in controlling cellular signalling processes in RA (rheumatoid arthritis). Trx80, the 10 kDa C-terminal truncated form of Trx, is a potent mitogenic cytokine and is involved in the Th1 response. In the present study, we have investigated the ability of synoviocytes from five RA patients to induce Trx80 after ex vivo stimulation by the pro-inflammatory cytokines IL-1β (interleukin-1β) and TNF-α (tumour necrosis factor-α) or by H2O2. Synoviocytes from five OA (osteoarthritis) patients were used as controls. Immunoprecipitation assays using two different antibodies showed that RA, but not OA, cells expressed intact Trx80 protein in culture even when not stimulated. Treatment with pro-inflammatory cytokines alone or in combination enhanced this basal production and induced the extracellular release of Trx80 by all of the RA cells tested. Under our experimental conditions, the rate of Trx80 release from RA cells was approx. 30% of the total Trx produced. In contrast, Trx80 was not detected in response to H2O2 in RA or OA synoviocyte lysates and their respective culture supernatants, indicating that the oxidative process induced by H2O2 in synoviocytes was unable to modify Trx80 release. Moreover, Trx80 induced synoviocyte proliferation as evaluated by [3H]thymidine incorporation. These results highlight the effect of the inflammatory process on the release of both Trx and Trx80 from RA synoviocytes, and suggest that the cytokine-induced increase in Trx80 cell release may constitute a link between inflammation and the immune system in RA.
Isotope-Coded Affinity Tagging of Proteins
Authors: Aebersold Ruedi , Griffin Timothy J. , Donohoe Sam 
Published: July 2007

INTRODUCTIONQuantitative proteomics has traditionally been performed using 2D gel electrophoresis, where quantitation is accomplished by recreating differences in the staining patterns of proteins derived from two states of cell populations or tissues from a similar biological system. More recently, mass spectrometry (MS) methods based on stable isotope quantitation have been developed that show significant potential for differential expression proteomic studies. One such in vitro method, described in this protocol, involves the use of isotope-coded affinity tags (ICATs) with three functional moieties: a cysteine reactive moiety, a linker with either eight hydrogens (the light form of the reagent) or eight deuteriums (the heavy form of the reagent, having an isotope code or mass tag of 8 Da), and a biotin moiety (the affinity tag). Using this technique, the cysteine side chains in complex mixtures of proteins from two different states of a cell population (e.g., normal vs. disease) are reduced and alkylated using the light form of the reagent (d0-labeled tag) in one cell state and the heavy form of the reagent (d8-labeled tag) for proteins in the second cell state. The two mixtures (d0 and d8 labeled) are then combined and subjected to proteolytic digestion (typically, with trypsin and/or Lys-C). Generated cysteine-containing peptides are affinity-purified using an avidin column, resulting in a “simplified” mixture of peptides that contains ~10-fold fewer peptides than the original mixture. These peptides are analyzed by MS, and quantitation information based on the relative abundance of the d0 and d8 isotopes is obtained. The identification of proteins is obtained from the peptide molecular mass and MS/MS-derived amino acid sequence.
Genome Modification by Inclusion of loxP Transgene Sequences: Figure 1.
Authors: Ohtsubo Kazuaki , Marth Jamey D. 
Published: July 2007

INTRODUCTIONWe describe here a procedure for introducing loxP sites into the mammalian genome. A typical gene-targeting approach to create a conditional null allele is presented, in which the initial placement of loxP sites is not deleterious to allele function. This can be modified to include knock-ins of point mutations, with such mutations flanked by loxP sites that can then be recombined by Cre expression. The choice of sequence or regulatory element to modify is dependent on the experimental design. Consideration must be given to the possible production of truncated and altered gene sequence products, or otherwise aberrantly functioning alleles.
Long-Term Two-Photon Transcranial Imaging of Synaptic Structures in the Living Brain
Authors: Grutzendler Jaime , Gan Wen-Biao 
Published: July 2007

INTRODUCTIONThis is a detailed protocol for long-term transcranial imaging of neuronal structures in the brains of living mice, using two-photon microscopy. It has been used to image individual dendritic spines and axonal varicosities in various mouse brain areas, such as visual, somatosensory, motor, and frontal cortices, over intervals of up to 4 months. This long-term transcranial imaging approach allows detailed structural and functional changes of synapses to be monitored during learning and memory processes, as well as in neurological disease models. It also provides a sensitive tool to detect the effects of various pharmacological and therapeutic interventions on cells in the living brain.
Differential Interference Contrast (DIC) Imaging of Living Cells: Figure 1.
Authors: Ziv Noam E. , Schiller Jackie 
Published: July 2007

INTRODUCTIONThis protocol describes the use of electronically enhanced, differential interference contrast (DIC) imaging techniques for the study of living cells. Methods for DIC imaging of cells using an inverted microscope and for infrared (IR) imaging of brains slices using an upright microscope are presented. DIC microscopy (also known as Nomarski microscopy) is extremely useful for resolving individual cells and cellular organelles in live, unstained tissue. The data obtained are valuable in their own right, as well as for complementing fluorescence microscopy data. DIC microscopy can be applied to cell culture, brain slices, and even intact organisms (such as embryos). High-quality images of living cells in brain slices can also be obtained using a combination of DIC optics and IR video microscopy.
Sagittal Explant Culture for 3D Confocal Time-Lapse Analysis of Chick Peripheral Nervous System Formation: Figure 1.
Authors: Kasemeier-Kulesa Jennifer C. , Lefcort Frances , Kulesa Paul M. 
Published: July 2007

INTRODUCTIONThe peripheral nervous system (PNS) regulates key events within the body including breathing, heart rate, and pain and temperature sensation. In the trunk of the developing embryo, neural crest (NC) cells that follow a ventro-medial pathway form the dorsal root ganglia (DRG) and sympathetic ganglia (SG) of the PNS. The cellular and molecular mechanisms that mediate the formation of the PNS are not completely understood due to the lack of a model system to monitor NC cell migratory behaviors deep within the embryo. Here, we describe a unique sagittal explant culture technique that allows for visualization of DRG and SG formation in the relatively intact chick embryo to assess potential molecules and signals influencing the formation of the PNS. By making a midline cut down the chick antero-posterior axis, each half of the embryo is an explant that can be imaged either from the medial perspective, to reveal events occurring deep within the embryo (SG formation), or from the lateral surface, to image events occurring in the dorso-lateral plane (DRG formation).
Conditional Mutagenesis of the Genome Using Site-Specific DNA Recombination: Figure 1.
Authors: Ohtsubo Kazuaki , Marth Jamey D. 
Published: July 2007

INTRODUCTIONAltering the genome of intact cells and organisms by site-specific DNA recombination has become an important gene-transfer methodology. DNA modifications produced by gene transfer and homologous recombination are typically static once integrated among target cell chromosomes. In contrast, the inclusion of exogenous recombinase target sequences within transferred DNA segments allows subsequent modifications to previously altered genomic structure that increase the utility of gene transfer and enhance experimental design. Creating tissue- and cell-type-specific genetic lesions in animal models, indelibly marking progenitors for cell fate mapping, inducing large-scale chromosomal rearrangements, and complementing gene defects in studies of phenotypic maintenance and reversion are all possible by directing recombinase expression using gene transfer among experimentally modified genomes. Moreover, this approach is effective in providing controlled data establishing genotype-phenotype relationships and allows for the excision of introduced marker genes that can affect neighboring chromatin structure and function. Although early work involved the yeast Flp recombinase, most studies in mammalian systems have used the Cre recombinase derived from bacteriophage P1. Both enzymes are members of the integrase family of recombinases but bind to distinct DNA target signals. Cre recombinase operates on the 34-bp loxP sequence and, like Flp, performs conservative recombination involving DNA segments positioned among these target sites.
Regulation of ligands for the activating receptor NKG2D
Authors: Mistry Anita R. , O'Callaghan Chris A. 
Published: July 2007

SummaryThe outcome of an encounter between a cytotoxic cell and a potential target cell depends on the balance of signals from inhibitory and activating receptors. Natural Killer group 2D (NKG2D) has recently emerged as a major activating receptor on T lymphocytes and natural killer cells. In both humans and mice, multiple different genes encode ligands for NKG2D, and these ligands are non‐classical major histocompatibility complex class I molecules. The NKG2D–ligand interaction triggers an activating signal in the cell expressing NKG2D and this promotes cytotoxic lysis of the cell expressing the ligand. Most normal tissues do not express ligands for NKG2D, but ligand expression has been documented in tumour and virus‐infected cells, leading to lysis of these cells. Tight regulation of ligand expression is important. If there is inappropriate expression in normal tissues, this will favour autoimmune processes, whilst failure to up‐regulate the ligands in pathological conditions would favour cancer development or dissemination of intracellular infection.
Xenogeneic human serum promotes leukocyte adhesion to porcine endothelium under flow conditions, possibly through the activation of the transcription factor NF‐κB
Authors: Morigi Marina , Zoja Carla , Colleoni Stella , Angioletti Stefania , Imberti Barbara , Remuzzi Andrea , Remuzzi Giuseppe 
Published: July 2007

Abstract: Endothelial cell activation and leukocyte infiltration are a consistent feature of discordant xenograft rejection. Here we evaluated whether xenogeneic serum, as a source of xenoreactive natural antibodies and complement, induced endothelial cell activation with consequent leukocyte adhesion under flow conditions. Porcine aortic endothelial cells (PAEC) were incubated for 1 hr 30 min or 5 hr with 10% homologous porcine serum (control) or 10% xenogeneic human serum and then perfused with total human leukocytes in a parallel plate flow chamber under laminar flow (1.5 dynes/cm2). Adherent cells were counted by digital image analysis. Xenogeneic human serum significantly (P<0.01) increased the number of adherent leukocytes as compared with porcine serum. A similar adhesive response was elicited by TNFα (100 U/ml), one of the most potent inducers of endothelial cell adhesive properties, here used as positive control.In order to elucidate possible mechanisms underlying endothelial cell activation by xenogeneic serum, we focussed on transcription factor NF‐κB, a central regulator for the induction of different genes, including adhesive molecules and chemoattractants. By confocal fluorescence microscopy, we observed a positive staining for NF‐κB (p65 subunit) in the nuclei of PAEC exposed for 1 hr 30 min to human serum, which indicated NF‐κB activation in this setting. At variance, in PAEC incubated with the homologous serum, NF‐κB was strictly localized in the cell cytoplasm. Treatment of PAEC exposed to xenogeneic serum with the NF‐κB inhibitors pyrrolidinedithiocarbamate (PDTC, 25 μM) and tosyl‐phechloromethylketone (TPCK, 25 μM) significantly (P<0.01) reduced leukocyte adhesion in respect to PAEC treated with human serum alone. Findings that xenogeneic serum promotes leukocyte‐endothelium interaction possibly through NF‐κB activation might be relevant for designing future therapeutic strategies aimed at prolonging xenograft survival.
Requirement of CD4 cells for induction and maintenance of unresponsiveness in islet xenografted mice
Authors: Lu Xiaoshan , Borel Jean F. 
Published: July 2007

Abstract: Long‐term survival of islet xenografts in the hamster to mouse model can be induced by a short‐course treatment with a nondepleting anti‐CD4 mAb but not with a depleting anti‐CD4 mAb (Lu et al. Xenotransplantation 1998; 5:154–1631. Although CD4 cells are known to play a key role in the rejection of islet xenografts, it remains unclear whether CD4 cells are also required for the induction and/or maintenance of specific unresponsiveness to xenografts. To investigate this problem, islets were isolated from golden hamsters and transplanted into streptozotocin‐induced diabetic CBA/J mice. Nondepleting mAb YTS 177.9 was used to block CD4 cells for the induction of islet xenograft unresponsiveness and subsequently depleting mAb GK1.5 to deplete CD4 cells in the unresponsive recipients.First, we now confirm that second donor‐strain xenografts were permanently accepted in recipients that had been unresponsive to the first grafts, whereas Lewis rat islet xenografts, used as third‐party grafts, were rejected like a primary graft within 7–8 days. Second, we depleted CD4 cells in recipient mice, which had been treated perioperatively with the nondepleting mAb YTS 177.9 and became unresponsive to their primary hamster islet graft, by using a depleting anti‐CD4 mAb at different time points post‐transplant. Depletion of CD4 cells in the unresponsive recipients by the depleting anti‐CD4 mAb GK1.5 did abrogate this unresponsive state, since the grafts were always rejected within an average of 25.5 days after the mAb GK1.5 injections. Therefore, our results strongly suggest that CD4 positive cells play an active suppressive role and that their presence in the recipients appears essential for both induction and maintenance of long‐term islet xenograft survival or specific unresponsiveness.
Einfluß der Ernährung auf den Papillarkörper der Pansenschleimhaut bei Kälbern
Authors: Scheurmann E. , Weyrauch K. D. 
Published: July 2007

AbstractThe purpose of this scanning electronmicroscopical study was to describe the structure of the lamina propria of the ruminal mucosa in calves on different diets.The surface epithelium was removed with 0.3 % acetic acid. The exposed lamina propria showed structural differences, both macroscopically and microscopically in the different dietary groups. At the submicroscopic level, however, no differences were observed.
The Comparative Morphology of the Muscle Tissues and Changes of Constituents in the Pig Types
Authors: Fehér György , Fazekas Sándor , Sándor István , Kollár Nándor 
Published: July 2007

SummaryThe authors have revealed the main value characteristics of pork production by testing in five different types of pig the volume of contractile and collagen proteins, that of proteoglycans, the constituents of blood and the enzymes of the blood plasma.The contractile proteins of the muscle tissues basically determine the quality of pork. The same applies to the water retention capacity, colloidal characteristics and glycogen content of meat. The amount of contractile proteins has decreased in the best meat producing types of pig. Parallel with the decrease of white meat, and with the increase in the volume of ham, chop and chuck the contractile protein content of muscles decreased. The scientific fact according to which there is a certain correlation among the changes in the volume of contractile proteins, blood sugar level, blood serum CPK and the intensity of activity of the LDH enzymes promotes the qualifying of live animals and the work of the geneticists aiming at the increasing of the contractile protein content of the muscle tissues of pigs by selection.According to tests carried out by us the primary cause of PSE changes is a decreased volume of contractile proteins. Increased stress sensitivity and all the other factors have but a secondary importance and are all consequential. The decrease in the quantity of contractile proteins or – it is better to put it this way – the lack of the proper amount of such proteins characterizing a fully developed pig's organism is caused by the nowadays usual breeding technologies and can be well explained by those selection activities which aim at a one‐sided kind of pork production.“Reluctante natura irritus labor est”
El Desarrollo del Estómago del Vacuno: Análisis desde el Prisma Morfológico y Morfométrico
Authors: Vivo J. M. , Robina A. 
Published: July 2007

SummaryThe Development of the Bovine Stomach, a Morphological and Morphometrical Analysis, Part IForty two embryos and fetuses of Frisian cattle, distributed onto 14 groups on the basis of crown‐rump lengths between 1.3cm (about 23 days) and 9.5cm (70 days), were used to study the morphogenesis of the bovine stomach. The work is divided into three parts. Part 1 deals with the ruminoreticulum and parts II and III the omasum and abomasum.