bluuebunny/crossref_metadata_2025_split huggingface dataset:
Supplementation of the dilution medium after thawing with reduced glutathione improves function and the in vitro fertilizing ability of frozen‐thawed bull spermatozoa
Authors: Gadea Joaquín , Gumbao David , Cánovas Sebastián , García‐Vázquez Francisco Alberto , Grullón Luis Alberto , Gardón Juan Carlos 
Published: May 2007

SummaryIn this study, we evaluated the effects of glutathione (l‐γ‐glutamyl‐l‐cysteinylglycine; GSH) supplementation of the thawing extender on bull semen parameters to compensate for the decrease in GSH content observed during sperm freezing. To address these questions fully, we used a set of functional sperm tests. These included tests of sperm motility assayed by computer‐assisted semen analysis, membrane lipid packing disorder, spontaneous acrosome reaction, free radical production [reactive oxygen species (ROS) generation], sperm chromatin condensation, DNA fragmentation by terminal deoxynucleotidyltransferase‐mediated dUTP nick‐end labelling and acridine orange staining measured by flow cytometry. Finally, the in vitro penetrability of in vitro matured oocytes and the in vitro production of embryos were evaluated. The main findings emerging from this study were that addition of GSH to the thawing medium resulted in: (i) a higher number of non‐capacitated viable spermatozoa; (ii) a reduction in ROS generation; (iii) lower chromatin condensation; (iv) lower DNA fragmentation; (v) higher oocyte penetration rate in vitro and (vi) higher in vitro embryo production compared with control group. Nevertheless, GSH had no significant effect on motion parameters or the occurrence of the spontaneous acrosome reaction. Addition of GSH to the thawing extender could be of significant benefit in improving the function and fertilizing capacity of frozen bull spermatozoa.
Improved gene expression signature of testicular carcinoma in situ
Authors: Almstrup Kristian , Leffers Henrik , Lothe Ragnhild A. , Skakkebæk Niels E. , Sonne Si B. , Nielsen John E. , Meyts Ewa Rajpert‐De , Skotheim Rolf I. 
Published: May 2007

SummaryThe carcinoma in situ (CIS) stage is the common precursor of testicular germ cell tumours (TGCTs) that arise in young adults. Within the past decade genome wide gene expression tools have been developed and have greatly advanced the insight into the biology of TGCTs. Two independent data sets on global gene expression in testicular CIS have been previously published. We have merged the two data sets on CIS samples (n = 6) and identified the shared gene expression signature in relation to expression in normal testis. Among the top‐20 highest expressed genes, one‐third was transcription factors and the list included some ‘novel’ CIS markers (i.e. DOCK11 and ANXA3). Genes related to biological terms ‘nucleic acid binding’ and ‘translational activity’ (e.g. transcription factors and ribosomal proteins, respectively) were consistently and significantly over‐represented. Some of the significantly over‐expressed genes in CIS cells were selected for validation by RT‐PCR (IFI16, DOCK11, and ANXA3), immunohistochemistry (HLXB9), or in situ hybridization (IFI16). High‐level analysis utilizing the Ingenuity pathway analysis tool indicated that networks relating to ‘gene expression in cancer’ and ‘embryonic development’ were significantly altered and could collectively affect cellular pathways like the WNT signalling cascade, which thus may be disrupted in testicular CIS. The merged CIS data from two different microarray platforms, to our knowledge, provide the most precise CIS gene expression signature to date.
Infertility among couples in a population‐based study in Iran: prevalence and associated risk factors
Authors: Safarinejad Mohammad Reza 
Published: May 2007

SummaryTo explore the prevalence and risk factors of infertility in Iran, a total of 12 285 ever‐married women aged 15–50 years old and their husbands (if available) were interviewed by 82 female general practitioners and answered a self‐administered questionnaire on several aspects of infertility. They were identified from the national population in 30 counties, and invited to a confidential interview. Data were obtained about their age, education, marital status, toxic habits, medical history, disabilities and illnesses, help‐seeking, economy, ethnicity, geographic location, contraceptive use and age at which they had first intercourse. This study used the definition of childlessness proposed by World Health Organization: ‘the woman has never conceived despite cohabitation and exposure to pregnancy for a period of 2 years’. The overall prevalence of infertility was 8% (95% CI: 3.2–15.0). The weighted national estimate of primary infertility was 4.6% (95% CI: 3.6–5.2). There was a pronounced regional pattern in the levels of primary infertility. The primary infertility increased significantly from 2.6 to 4.3 to 5.5% for the 1985–1989, 1990–1994 and 1995–2000 marriage cohorts. The prevalence of secondary infertility was 3.4% (95% CI: 2.4–5.1). Overall the prevalence of infertility falls within a relatively wide range being high in the Southern counties, and low in the Northern counties. The probability of first pregnancy at the end of 2 years of marriage was 0.78 for all ever‐married women. The prevalence of infertility increased with age (linear chi‐square 198.012, 1 d.f., p = 0.01). The age pattern of infertility also varies quite markedly across the counties analysed. No effect of race was detected; neither the intercept (analysis of covariance p = 0.36) nor the slope of the age relationship was influenced by race (analysis of covariance p = 0.41). Infertility were observed as significantly higher in the presence of history of tubo‐ovarian surgery [odds ratio (OR): 1.43; 95% CI: 1.28–2.23; p = 0.01], salpingitis (OR: 2.34; 95% CI: 1.31–4.3; p = 0.016), ectopic pregnancy (OR: 2.45; 95% CI: 1.90–3.44; p = 0.04), varicocele (OR: 2.85; 95% CI: 1.61–5.20; p = 0.01) and cryptorchidism (OR: 3.81; 95% CI: 2.51–4.28; p = 0.031). This study provides a quantitative estimate of the prevalence and main risk factors for infertility in Iranian couples. Yet, further studies on the cause of primary and secondary infertility and geographical variations in the incidence and prevalence of infertility in Iran are needed.
The Arabidopsis cohesin protein SYN3 localizes to the nucleolus and is essential for gametogenesis
Authors: Jiang Ling , Xia Ming , Strittmatter Lara I. , Makaroff Christopher A. 
Published: May 2007

Summaryα‐kleisins are core components of meiotic and mitotic cohesin complexes. Arabidopsis contains genes for four α‐kleisin proteins encoded by SYN genes. SYN1, a REC8 ortholog, is essential for meiosis, while SYN2 and SYN4 appear to be SCC1 orthologs and function in mitosis. Our analysis of AtSYN3 shows that it localizes primarily in the nucleolus of both meiotic and mitotic cells. Furthermore, analysis of plants containing an AtSYN3 T‐DNA knockout mutation demonstrated that it is essential for megagametogenesis and plays an important role in pollen. These results suggest that SYN3 may not function as part of a typical cohesin complex; rather it may have evolved a specialized role in controlling rDNA structure, transcription or rRNA processing.
The regulatory gamma subunit SNF4b of the sucrose non‐fermenting‐related kinase complex is involved in longevity and stachyose accumulation during maturation of Medicago truncatula seeds
Authors: Rosnoblet Claire , Aubry Catherine , Leprince Olivier , Vu Benoit Ly , Rogniaux Hélène , Buitink Julia 
Published: May 2007

SummaryThe sucrose non‐fermenting‐related kinase complex (SnRK1) is a heterotrimeric complex that plays a central role in metabolic adaptation to nutritional or environmental stresses. Here we investigate the role of a regulatory γ‐subunit of the complex, MtSNF4b, in Medicago truncatula seeds. Western blot indicated that MtSNF4b accumulated during seed filling, whereas it disappeared during imbibition of mature seeds. Gel filtration chromatography suggested that MtSNF4b assembled into a complex (450–600 kDa) at the onset of maturation drying, and dissociated during subsequent imbibition. Drying of desiccation‐tolerant radicles led to a reassembly of the complex, in contrast to sensitive tissues. Silencing of MtSNF4b using a RNA interference (RNAi) approach resulted in a phenotype with reduced seed longevity, evident from the reduction in both germination percentage and seedling vigour in aged RNAi MtSNF4b seeds compared with the wild‐type seeds. In parallel to the assembly of the complex, seeds of the RNAi MtSNF4b lines showed impaired accumulation of raffinose family oligosaccharides compared with control seeds. In mature seeds, the amount of stachyose was reduced by 50–80%, whereas the sucrose content was 60% higher. During imbibition, the differences in non‐reducing sugar compared with the control disappeared in parallel to the disassembly of the complex. No difference was observed in dry weight or reserve accumulation such as proteins, lipids and starch. These data suggest that the regulatory γ‐subunit MtSNF4b confers a specific and temporal function to SnRK1 complexes in seeds, improving seed longevity and affecting the non‐reducing sugar content at later stages of seed maturation.
Identification of regulatory pathways involved in the reacquisition of root growth after salt stress in Medicago truncatula
Authors: Merchan Francisco , Lorenzo Laura de , Rizzo Silvina González , Niebel Andreas , Manyani Hamid , Frugier Florian , Sousa Carolina , Crespi Martin 
Published: May 2007

SummaryRoot growth and function are determined by the action of environmental stresses through specific genes that adapt root development to these restrictive conditions. We have defined in vitro conditions affecting the growth and recovery of Medicago truncatula roots after a salt stress. A dedicated macroarray containing 384 genes, based on a large‐scale subtractive hybridization approach, was constructed and used to analyze gene expression during salt stress and recovery of root growth from this stress. Several potential regulatory genes were identified as being linked to this recovery process: a novel RNA‐binding protein, a small G‐protein homologous to ROP9, a receptor‐like kinase, two TF IIIA‐like and an AP2‐like transcription factors (TF), MtZpt2‐1, MtZpt2‐2 and MtAp2, and a histidine kinase associated with cytokinin transduction pathways. The two ZPT2‐type TFs were also rapidly induced by cold stress in roots. By analyzing transgenic M. truncatula plants showing reduced expression levels of both TFs and affected in their capacity to recover root growth after a salt stress, we identified potential target genes that were either activated or repressed in these plants. Overexpression of MtZpt2‐1 in roots conferred salt tolerance and affected the expression of three putative targets in the predicted manner: a cold‐regulated A (CORA) homolog, a flower‐promoting factor (FPF1) homolog and an auxin‐induced proline‐rich protein (PRP) gene. Hence, regulatory networks depending on TFIIIA‐like transcription factors are involved in the control of root adaptation to salt stress.
DELLA protein function in growth responses to canopy signals
Authors: Djakovic‐Petrovic Tanja , Wit Mieke de , Voesenek Laurentius A.C.J. , Pierik Ronald 
Published: May 2007

SummaryPlants can sense neighbour competitors through light‐quality signals and respond with shade‐avoidance responses. These include increased shoot elongation, which enhances light capture and thus competitive power. Such plant–plant interactions therefore profoundly affect plant development in crowded populations. Shade‐avoidance responses are tightly coordinated by interactions between light signals and hormones, with essential roles for the phytochrome B photoreceptor [sensing the red:far red (R:FR) ratio] and the hormone gibberellin (GA). The family of growth‐suppressing DELLA proteins are targets for GA signalling and are proposed to integrate signals from other hormones. However, the importance of these regulators has not been studied in the ecologically relevant, complex realm of plant canopies. Here we show that DELLA abundance is regulated during growth responses to neighbours in dense Arabidopsis stands. This occurs in a R:FR‐dependent manner in petioles, depends on GA, and matches the induction kinetics of petiole elongation. Similar interactions were observed in the growth response of seedling hypocotyls and are general for a second canopy signal, reduced blue light. Enhanced DELLA stability in the gai mutant inhibits shade‐avoidance responses, indicating that DELLA proteins constrain shade‐avoidance. However, using multiple DELLA knockout mutants, we show that the observed DELLA breakdown is not sufficient to induce shade‐avoidance in petioles, but plays a more central role in hypocotyls. These data provide novel information on the regulation of shade‐avoidance under ecologically important conditions, defining the importance of DELLA proteins and GA and unravelling the existence of GA‐ and DELLA‐independent mechanisms.
HLA‐B*5701 typing: evaluation of an allele‐specific polymerase chain reaction melting assay
Authors: Hammond E. , Mamotte C. , Nolan D. , Mallal S. 
Published: May 2007

AbstractInheritance of HLA‐B*5701 is a strong predictor of a hypersensitivity reaction to the anti‐HIV drug abacavir. The identification of susceptible individuals prior to the institution of abacavir therapy is therefore of clinical importance and has generated demand for a simple and rapid diagnostic test for carriage of HLA‐B*5701. In this study, we describe the development of such a method based on allele‐specific polymerase chain reaction (AS‐PCR) and melting curve analysis. Ninety‐six patient samples including 36 HLA‐B*5701‐positive samples and 60 HLA‐B*5701‐negative samples were analysed. Compared with sequence‐based typing, this method had 100% sensitivity and specificity for the HLA‐B*5701 allele. In conclusion, the AS‐PCR/melting curve approach minimises post‐polymerase chain reaction handling processing and provides an attractive alternative to currently described AS‐PCR methods.
Pre‐screening of miniature swine may reduce the risk of transmitting human tropic recombinant porcine endogenous retroviruses
Authors: Hector Ralph D. , Meikle Sharon , Grant Louise , Wilkinson Robert A. , Fishman Jay A. , Scobie Linda 
Published: May 2007

Abstract: Background:  It has been reported that peripheral blood mononuclear cells from miniature swine are capable of transmitting human tropic porcine endogenous retrovirus (PERV) recombinants to both human and pig cells. It has been suggested that these recombinants are exogenous and/or driven by one or more critical loci present in the pig genome.Methods and Results:  Genomic analysis of a miniature swine capable of transmitting human tropic replication competent (HTRC) recombinant PERV‐A/C identified a PERV‐C provirus in a region with homology to sequences located on chromosome 7. In “null” swine, incapable of in vitro transmission of PERV to human or pig cells, amplification using specific primers revealed that only two of five animals retained this locus in comparison to a total of five out of five transmitters (recombinant PERV‐A/C transmission to both human and pig cells) and seven out of seven non‐transmitters (replication of non‐recombinant PERV in pig cells only).Conclusion:  These data suggest that further analysis of these loci may provide a genetic basis for identifying pigs that are less likely to transmit human tropic PERV and would, therefore, be more suitable as source animals for human xenotransplantation.
Porcine PD‐L1: cloning, characterization, and implications during xenotransplantation
Authors: Jeon Dae‐Hyun , Oh Keunhee , Oh Byoung C. , Nam Dong H. , Kim Chi H. , Park Hyung‐Bae , Cho Jaejin , Lee Jeong R. , Lee Dong‐Sup , Lee Gene 
Published: May 2007

Abstract: Background:  Effective intervention achieved by manipulating cell‐mediated xenogeneic immune responses would critically increase the clinical feasibility of xenotransplantation as immediate hyperacute rejections become controllable through genetic modulations of donor organs. Endogenous negative regulatory signals like the programmed death 1 (PD‐1)‐programmed death ligand 1 (PD‐L1) system are candidate targets for the control of cell‐mediated xenogeneic immune response.Methods: A porcine PD‐L1 molecule was cloned using RACE (rapid amplification of cDNA ends) technology based on the human PD‐L1 sequence. The functional effects of cloned porcine PD‐L1 were tested on human CD4+ T cell activation using porcine PD‐L1‐transfected bystander cells. Cellular proliferation was monitored by [3H] thymidine incorporation, and human T cell apoptosis was measured by flow cytometry.Results: Porcine PD‐L1 (GenBank accession number AY837780) was found to have 73.8% sequence homology with human PD‐L1 and to contain two immunoglobulin domains in its extracellular region. Moreover, porcine PD‐L1 expressed on Chinese hamster ovary (CHO) cells inhibited human CD4+ T cell proliferation stimulated with anti‐CD3 only or anti‐CD3 plus anti‐CD28. Percentages of apoptotic activated human T cells increased by over 30% in the presence of porcine PD‐L1/CHO cells, and the addition of recombinant human PD‐1‐Fc fusion proteins during human T cell activation reversed the inhibitory effects of porcine PD‐L1.Conclusions: Cloned porcine PD‐L1 showed high sequence homology with human PD‐L1 and a similar molecular structure. Moreover, porcine PD‐L1 inhibited human CD4+ T cell activation in human PD‐1‐dependent manner, and this involved activated T cell apoptosis. The authors suggest that PD‐1‐PD‐L1 might play an important endogenous immune regulatory role during xenogeneic transplantation, and that the effective application of this system would improve transplanted xenogeneic organ survival.
Divergent effects of ephedrine and phenylephrine on cardiovascular hemodynamics of near‐term fetal sheep exposed to hypoxemia and maternal hypotension
Authors: Erkinaro T. , Mäkikallio K. , Acharya G. , Päkkilä M. , Kavasmaa T. , Huhta J. C. , Alahuhta S. , Räsänen J. 
Published: May 2007

Background:  We hypothesized that the administration of ephedrine and phenylephrine for maternal hypotension modifies cardiovascular hemodynamics in near‐term sheep fetuses.Methods:  At 115–136 days of gestation, chronically instrumented, anesthetized ewes with either normal placental function or increased placental vascular resistance after placental embolization were randomized to receive boluses of ephedrine (n = 12) or phenylephrine (n = 12) for epidural‐induced hypotension after a short period of hypoxemia. Fetal cardiovascular hemodynamics were assessed by Doppler ultrasonography at baseline, during hypotension and after vasopressor treatment.Results:  During hypotension, fetal PO2 decreased and proximal branch pulmonary arterial and pulmonary venous vascular impedances increased. Additionally, in the embolized fetuses, the time‐velocity integral ratio between the antegrade and retrograde blood flow components of the aortic isthmus decreased. These parameters were restored to baseline conditions by ephedrine but not by phenylephrine. With phenylephrine, weight‐indexed left ventricular cardiac output and ejection force decreased in the non‐embolized fetuses, and the proportion of isovolumetric contraction time of the total cardiac cycle was elevated in the embolized fetuses.Conclusions:  After exposure to hypoxemia and maternal hypotension, ephedrine restored all fetal cardiovascular hemodynamic parameters to baseline. Phenylephrine did not reverse fetal pulmonary vasoconstriction or the relative decrease in the net forward flow through the aortic isthmus observed in fetuses with increased placental vascular resistance. Moreover, fetal left ventricular function was impaired during phenylephrine administration.
Single bolus of intravenous ketamine for anesthetic induction decreases oculocardiac reflex in children undergoing strabismus surgery
Authors: Choi S. H. , Lee S. J. , Kim S. H. , Kim J. H. , Kwon H. H. , Shin Y. S. , Lee K. Y. 
Published: May 2007

Background:  Oculocardiac reflex (OCR) is a major complication of pediatric strabismus surgery. The aim of the present study was to determine whether a single bolus of intravenous (i.v.) ketamine for anesthetic induction can decrease OCR in children undergoing strabismus surgery.Methods:  One hundred and twenty healthy children undergoing strabismus surgery were allocated to three groups using double‐blind randomization. Anesthesia was induced with propofol 3 mg/kg in Group P, ketamine 1 mg/kg in Group K1, or ketamine 2 mg/kg in Group K2. Anesthesia was maintained with 3% sevoflurane in 50% N2O/O2 in all patients. The baseline heart rate was obtained 30 s prior to the first traction of the extraocular muscle (EOM). OCR was defined as a development of arrhythmia or a decrease of more than 20% of the baseline heart rate during EOM traction.Results:  The incidence of OCR was significantly lower in the ketamine groups (4/40 and 1/40 in Group K1 and K2, respectively) compared with the propofol group (14/40).Conclusion:  A single bolus of i.v. ketamine 1 or 2 mg/kg for anesthetic induction results in a lower incidence of OCR than propofol when combined with sevoflurane for maintenance in children undergoing strabismus surgery.
Detecting local adaptation in a natural plant–pathogen metapopulation: a laboratory vs. field transplant approach
Authors: LAINE ANNA‐LIISA 
Published: May 2007

AbstractAntagonistic coevolution between hosts and parasites in spatially structured populations can result in local adaptation of parasites. Traditionally parasite local adaptation has been investigated in field transplant experiments or in the laboratory under a constant environment. Despite the conceptual importance of local adaptation in studies of (co)evolution, to date no study has provided a comparative analysis of these two methods. Here, using information on pathogen population dynamics, I tested local adaptation of the specialist phytopathogen,Podosphaera plantaginis, to its host,Plantago lanceolataat three different spatial scales: sympatric host population, sympatric host metapopulation and allopatric host metapopulations. The experiment was carried out as a field transplant experiment with greenhouse‐reared host plants from these three different origins introduced into four pathogen populations. In contrast to results of an earlier study performed with these same host and parasite populations under laboratory conditions, I did not find any evidence for parasite local adaptation. For interactions governed by strain‐specific resistance, field studies may not be sensitive enough to detect mean parasite population virulence. Given that parasite transmission potential may be mediated by the abiotic environment and genotype‐by‐environment interactions, I suggest that relevant environmental variation should be incorporated into laboratory studies of parasite local adaptation.
Moult speed constrains the expression of a carotenoid‐based sexual ornament
Authors: SERRA L. , GRIGGIO M. , LICHERI D. , PILASTRO A. 
Published: May 2007

AbstractWe investigated the effect of moult speed on the expression of a sexually selected, carotenoid‐based feather ornament in the rock sparrow (Petronia petronia). We experimentally accelerated the moult speed of a group of birds by exposing them to a rapidly decreasing photoperiod and compared the area and the spectral characteristics of their ornaments with those of control birds. Birds with accelerated moulting rate showed a smaller yellow patch with lower yellow reflectance compared to their slow‐moulting counterparts. Considering that the time available for moulting is usually constrained between the end of the breeding season and migration or wintering, carotenoid feather ornaments, whose expression is mediated by moult speed, may convey long term information about an individual's condition, potentially encompassing the previous breeding season. Furthermore, the observed trade‐off between moult speed and ornament expression may represent a previously unrecognized selective advantage for early breeding birds.