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Strous M, Fuerst JA, Kramer EH, Logemann S, Muyzer G, van de Pas-Schoonen KT, Webb R, Kuenen JG, Jetten MS. Missing lithotroph identified as new planctomycete. Nature 1999; 400:446-9. [PMID: 10440372 DOI: 10.1038/22749] [Citation(s) in RCA: 820] [Impact Index Per Article: 31.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
With the increased use of chemical fertilizers in agriculture, many densely populated countries face environmental problems associated with high ammonia emissions. The process of anaerobic ammonia oxidation ('anammox') is one of the most innovative technological advances in the removal of ammonia nitrogen from waste water. This new process combines ammonia and nitrite directly into dinitrogen gas. Until now, bacteria capable of anaerobically oxidizing ammonia had never been found and were known as "lithotrophs missing from nature". Here we report the discovery of this missing lithotroph and its identification as a new, autotrophic member of the order Planctomycetales, one of the major distinct divisions of the Bacteria. The new planctomycete grows extremely slowly, dividing only once every two weeks. At present, it cannot be cultivated by conventional microbiological techniques. The identification of this bacterium as the one responsible for anaerobic oxidation of ammonia makes an important contribution to the problem of unculturability.
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MESH Headings
- Ammonia/metabolism
- Bacteria/classification
- Bacteria/isolation & purification
- Bacteria/metabolism
- Bacteria/ultrastructure
- Bacteria, Anaerobic/classification
- Bacteria, Anaerobic/isolation & purification
- Bacteria, Anaerobic/metabolism
- Bacteria, Anaerobic/ultrastructure
- Biofilms/classification
- DNA, Bacterial/classification
- DNA, Bacterial/genetics
- Molecular Sequence Data
- Oxidation-Reduction
- Phylogeny
- RNA, Bacterial/classification
- RNA, Bacterial/genetics
- RNA, Ribosomal, 16S/classification
- RNA, Ribosomal, 16S/genetics
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820 |
2
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Eckstein-Ludwig U, Webb RJ, Van Goethem IDA, East JM, Lee AG, Kimura M, O'Neill PM, Bray PG, Ward SA, Krishna S. Artemisinins target the SERCA of Plasmodium falciparum. Nature 2003; 424:957-61. [PMID: 12931192 DOI: 10.1038/nature01813] [Citation(s) in RCA: 684] [Impact Index Per Article: 31.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2003] [Accepted: 05/12/2003] [Indexed: 11/08/2022]
Abstract
Artemisinins are extracted from sweet wormwood (Artemisia annua) and are the most potent antimalarials available, rapidly killing all asexual stages of Plasmodium falciparum. Artemisinins are sesquiterpene lactones widely used to treat multidrug-resistant malaria, a disease that annually claims 1 million lives. Despite extensive clinical and laboratory experience their molecular target is not yet identified. Activated artemisinins form adducts with a variety of biological macromolecules, including haem, translationally controlled tumour protein (TCTP) and other higher-molecular-weight proteins. Here we show that artemisinins, but not quinine or chloroquine, inhibit the SERCA orthologue (PfATP6) of Plasmodium falciparum in Xenopus oocytes with similar potency to thapsigargin (another sesquiterpene lactone and highly specific SERCA inhibitor). As predicted, thapsigargin also antagonizes the parasiticidal activity of artemisinin. Desoxyartemisinin lacks an endoperoxide bridge and is ineffective both as an inhibitor of PfATP6 and as an antimalarial. Chelation of iron by desferrioxamine abrogates the antiparasitic activity of artemisinins and correspondingly attenuates inhibition of PfATP6. Imaging of parasites with BODIPY-thapsigargin labels the cytosolic compartment and is competed by artemisinin. Fluorescent artemisinin labels parasites similarly and irreversibly in an Fe2+-dependent manner. These data provide compelling evidence that artemisinins act by inhibiting PfATP6 outside the food vacuole after activation by iron.
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22 |
684 |
3
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Gosden RG, Baird DT, Wade JC, Webb R. Restoration of fertility to oophorectomized sheep by ovarian autografts stored at -196 degrees C. Hum Reprod 1994; 9:597-603. [PMID: 8046009 DOI: 10.1093/oxfordjournals.humrep.a138556] [Citation(s) in RCA: 491] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Cortical slices were prepared from the right ovaries of six lambs and either grafted directly to the ovarian pedicles of origin or cooled slowly to liquid nitrogen temperatures in medium containing dimethylsulphoxide. Three weeks later, the contra-lateral ovary was removed and replaced with frozen-thawed slices from the same animal. Two of the animals mated during their second oestrous cycle 3-4 months later and the remainder had at least one ovulatory cycle. The pregnancies reached full-term development, one lamb being derived from an ovulation in a fresh graft and the other from a frozen-thawed graft. None of the sheep had peripheral plasma concentrations of follicle stimulating hormone or luteinizing hormone consistently in the castrate range, and only one graft was devoid of follicles when the animals were slaughtered 9 months after the operations. Grafts with primordial follicles always contained developing follicles, which occasionally attained pre-ovulatory sizes of 7 mm in diameter. A corpus albicans was present in five grafts. Since all developing follicles had degenerated 1 week after grafting in an additional ewe, the large follicles in long-term grafts had presumably commenced growing after the operation. There were no obvious differences between fresh and frozen-thawed grafts in either appearance or weight, and all had apparently grown since implantation. Despite substantial depletion of primordial follicle numbers, the results indicated that frozen storage and replacement of a patient's own ovarian tissue might be practicable when fertility potential is threatened by chemotherapy/radiotherapy.
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31 |
491 |
4
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Symmons D, Turner G, Webb R, Asten P, Barrett E, Lunt M, Scott D, Silman A. The prevalence of rheumatoid arthritis in the United Kingdom: new estimates for a new century. Rheumatology (Oxford) 2002; 41:793-800. [PMID: 12096230 DOI: 10.1093/rheumatology/41.7.793] [Citation(s) in RCA: 407] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND It is 40 yr since the last age- and sex-specific estimates of the prevalence of rheumatoid arthritis (RA) for the UK were published. Since then the classification criteria for RA have been revised and there has been evidence of a fall in the incidence of RA, especially in women. OBJECTIVES To estimate the age- and sex-specific point prevalence of RA (defined as fulfilment of a modification of the 1987 ACR classification criteria for RA on the day of assessment). The estimate was made in the primary care setting in Norfolk, UK. METHODS A stratified random sample was drawn from seven age and gender bands. The 7050 individuals selected were mailed a screening questionnaire. Positive responders were invited to attend for a clinical examination. The sample was matched against the names in the Norfolk Arthritis Register (NOAR), a register of incident cases of inflammatory polyarthritis which has been in existence since 1990. RESULTS The overall response rate was 82%. Sixty-six cases of RA were identified. Extrapolated to the population of the UK, the overall minimum prevalence of RA is 1.16% in women and 0.44% in men. A number of incident cases of RA previously notified to NOAR were not identified as cases in the survey because they had entered into treatment-induced remission. In addition, some cases who failed to attend for examination had significant disability. These prevalence figures are therefore an underestimate. CONCLUSIONS The prevalence of RA in women, but not in men, in the UK may have fallen since the 1950s.
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407 |
5
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Baird DT, Webb R, Campbell BK, Harkness LM, Gosden RG. Long-term ovarian function in sheep after ovariectomy and transplantation of autografts stored at -196 C. Endocrinology 1999; 140:462-71. [PMID: 9886858 DOI: 10.1210/endo.140.1.6453] [Citation(s) in RCA: 275] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We have previously demonstrated that ovarian function and fertility can be preserved in sheep after castration by autotransplantation of cryopreserved strips of ovarian cortex. In the current experiments we have investigated the long term survival of such grafts by detailed measurements of ovarian function for a period of nearly 2 yr after autotransplantation. After ovariectomy and transplantation of frozen/thawed grafts, the concentrations of FSH and LH rose to castrate levels for about 14 weeks before falling gradually to reach near-normal levels at about 60 weeks. In the breeding season from October 1994 to March 1995, all ewes had 5-10 estrous cycles that were similar in length to those in the 4 control ewes. Luteal function as indicated by the progesterone concentration was identical before and 11 months after transplantation. In contrast, the basal concentrations of FSH and LH were persistently raised throughout the luteal phase, but showed a normal decline during the follicular phase. The concentration of inhibin A in ovarian venous plasma measured at the end of the experiment 22 months after transplantation was significantly lower than that in control ewes (mean +/- SE, 409 +/- 118 vs. 1914 +/- 555 pg/ml; P < 0.004). Transplantation of frozen/thawed ovarian tissue to SCID mice demonstrated that about 28% of primordial follicles survived the procedure. All of the ovaries transplanted into sheep contained large antral follicles and/or cysts, but very few primordial oocytes when recovered at autopsy after 22 months. These results demonstrate that despite a drastic reduction in the total number of primordial follicles, cyclical ovarian function is preserved in sheep after autotransplantation of frozen/thawed ovarian tissue and provide experimental confirmation that such a technique could provide a means of preserving fertility in women undergoing chemo- or radiotherapy for malignant disease.
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26 |
275 |
6
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Robinson GS, Pierce EA, Rook SL, Foley E, Webb R, Smith LE. Oligodeoxynucleotides inhibit retinal neovascularization in a murine model of proliferative retinopathy. Proc Natl Acad Sci U S A 1996; 93:4851-6. [PMID: 8643492 PMCID: PMC39368 DOI: 10.1073/pnas.93.10.4851] [Citation(s) in RCA: 239] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Diseases characterized by retinal neovascularization are among the principal causes of visual loss worldwide. The hypoxia-stimulated expression of vascular endothelial growth factor (VEGF) has been implicated in the proliferation of new blood vessels. We have investigated the use of antisense phosphorothioate oligodeoxynucleotides against murine VEGF to inhibit retinal neovascularization and VEGF synthesis in a murine model of proliferative retinopathy. Intravitreal injections of two different antisense phosphorothioate oligodeoxynucleotides prior to the onset of proliferative retinopathy reduced new blood vessel growth a mean of 25 and 31% compared with controls. This inhibition was dependent on the concentration of antisense phosphorothioate oligodeoxynucleotides and resulted in a 40-66% reduction in the level of VEGF protein, as determined by Western blot analysis. Control (sense, nonspecific) phosphorothioate oligodeoxynucleotides did not cause a significant reduction in retinal neovascularization or VEGF protein levels. These data further establish a fundamental role for VEGF expression in ischemia-induced proliferative retinopathies and a potential therapeutic use for antisense phosphorothioate oligodeoxynucleotides.
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research-article |
29 |
239 |
7
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Gutiérrez CG, Campbell BK, Webb R. Development of a long-term bovine granulosa cell culture system: induction and maintenance of estradiol production, response to follicle-stimulating hormone, and morphological characteristics. Biol Reprod 1997; 56:608-16. [PMID: 9047004 DOI: 10.1095/biolreprod56.3.608] [Citation(s) in RCA: 237] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The objectives of this study were to develop a serum-free bovine granulosa cell culture system in which FSH-responsive estradiol production could be induced and maintained, and to use this system to evaluate the effects of FSH, insulin, and IGF-I on steroidogenesis and proliferation of bovine granulosa cells from different follicle size categories (< 4-, 4-8, and > 8-mm diameter). In the presence of FSH, granulosa cells from small follicles differentiated in vitro, and estradiol secretion increased with time (p < 0.01) so that by the end of the culture period it was similar to that of cells from large follicles. Granulosa cells from medium and large follicles secreted estradiol throughout the culture period. Cells cultured in plasma-coated culture wells had an increased proliferative response but had lower estradiol production compared to cells cultured under serum-free conditions (p < 0.01). Insulin promoted proliferation and estradiol production by granulosa cells from the three follicle-size categories (p < 0.01). Physiological concentrations of FSH induced proliferation and estradiol secretion (p < 0.01) by granulosa cells in a dose-responsive manner. The inclusion of IGF-I in the culture system enhanced proliferation and estradiol production (p < 0.01), even in the absence of gonadotropic support, demonstrating the gonadotropic characteristics of this growth factor. These results demonstrate the development of a relevant physiological culture system for bovine granulosa cells. This system will permit the detailed study of the key factors controlling the differentiation and proliferation of bovine granulosa cells.
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28 |
237 |
8
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Lin Q, Lu J, Yanagisawa H, Webb R, Lyons GE, Richardson JA, Olson EN. Requirement of the MADS-box transcription factor MEF2C for vascular development. Development 1998; 125:4565-74. [PMID: 9778514 DOI: 10.1242/dev.125.22.4565] [Citation(s) in RCA: 228] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
The embryonic vasculature develops from endothelial cells that form a primitive vascular plexus which recruits smooth muscle cells to form the arterial and venous systems. The MADS-box transcription factor MEF2C is expressed in developing endothelial cells and smooth muscle cells (SMCs), as well as in surrounding mesenchyme, during embryogenesis. Targeted deletion of the mouse MEF2C gene resulted in severe vascular abnormalities and lethality in homozygous mutants by embryonic day 9.5. Endothelial cells were present and were able to differentiate, but failed to organize normally into a vascular plexus, and smooth muscle cells did not differentiate in MEF2C mutant embryos. These vascular defects resemble those in mice lacking the vascular-specific endothelial cell growth factor VEGF or its receptor Flt-1, both of which are expressed in MEF2C mutant embryos. These results reveal multiple roles for MEF2C in vascular development and suggest that MEF2-dependent target genes mediate endothelial cell organization and SMC differentiation.
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27 |
228 |
9
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Gutierrez CG, Ralph JH, Telfer EE, Wilmut I, Webb R. Growth and antrum formation of bovine preantral follicles in long-term culture in vitro. Biol Reprod 2000; 62:1322-1328. [PMID: 10775183 DOI: 10.1095/biolreprod62.5.1322] [Citation(s) in RCA: 221] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Culture of preantral follicles has important biotechnological implications through its potential to produce large quantities of oocytes for embryo production and transfer. A long-term culture system for bovine preantral follicles is described. Bovine preantral follicles (166 +/- 2.15 micrometer), surrounded by theca cells, were isolated from ovarian cortical slices. Follicles were cultured under conditions known to maintain granulosa cell viability in vitro. The effects of epidermal growth factor (EGF), insulin-like growth factor (IGF)-I, FSH, and coculture with bovine granulosa cells on preantral follicle growth were analyzed. Follicle and oocyte diameter increased significantly (P < 0.05) with time in culture. FSH, IGF-I, and EGF stimulated (P < 0.05) follicle growth rate but had no effect on oocyte growth. Coculture with granulosa cells inhibited FSH/IGF-I-stimulated growth. Most follicles maintained their morphology throughout culture, with the presence of a thecal layer and basement membrane surrounding the granulosa cells. Antrum formation, confirmed by confocal microscopy, occurred between Days 10 and 28 of culture. The probability of follicles reaching antrum development was 0.19 for control follicles. The addition of growth factors or FSH increased (P < 0.05) the probability of antrum development to 0.55. Follicular growth appeared to be halted by slower growth of the basement membrane, as growing follicles occasionally burst the basement membrane, extruding their granulosa cells. In conclusion, a preantral follicle culture system in which follicle morphology can be maintained for up to 28 days has been developed. In this system, FSH, EGF, and IGF-I stimulated follicle growth and enhanced antrum formation. This culture system may provide a valuable approach for studying the regulation of early follicular development and for production of oocytes for nuclear/embryo transfer, but further work is required.
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25 |
221 |
10
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Chagas LM, Bass JJ, Blache D, Burke CR, Kay JK, Lindsay DR, Lucy MC, Martin GB, Meier S, Rhodes FM, Roche JR, Thatcher WW, Webb R. Invited review: New perspectives on the roles of nutrition and metabolic priorities in the subfertility of high-producing dairy cows. J Dairy Sci 2007; 90:4022-32. [PMID: 17699018 DOI: 10.3168/jds.2006-852] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Management, nutrition, production, and genetics are the main reasons for the decline in fertility in the modern dairy cow. Selection for the single trait of milk production with little consideration for traits associated with reproduction in the modern dairy cow has produced an antagonistic relationship between milk yield and reproductive performance. The outcome is a multi-factorial syndrome of subfertility during lactation; thus, to achieve a better understanding and derive a solution, it is necessary to integrate a range of disciplines, including genetics, nutrition, immunology, molecular biology, endocrinology, metabolic and reproductive physiology, and animal welfare. The common theme underlying the process is a link between nutritional and metabolic inputs that support complex interactions between the gonadotropic and somatotropic axes. Multiple hormonal and metabolic signals from the liver, pancreas, muscle, and adipose tissues act on brain centers regulating feed intake, energy balance, and metabolism. Among these signals, glucose, fatty acids, insulin-like growth factor-I, insulin, growth hormone, ghrelin, leptin, and perhaps myostatin appear to play key roles. Many of these factors are affected by changes in the somatotropic axis that are a consequence of, or are needed to support, high milk production. Ovarian tissues also respond directly to metabolic inputs, with consequences for folliculogenesis, steroidogenesis, and the development of the oocyte and embryo. Little doubt exists that appropriate nutritional management before and after calving is essential for successful reproduction. Changes in body composition are related to the processes that lead to ovulation, estrus, and conception. However, better indicators of body composition and measures of critical metabolites are required to form precise nutritional management guidelines to optimize reproductive outcomes. The eventual solution to the reduction in fertility will be a new strategic direction for genetic selection that includes fertility-related traits. However, this will take time to be effective, so, in the short term, we need to gain a greater understanding of the interactions between nutrition and fertility to better manage the issue. A greater understanding of the phenomenon will also provide markers for more targeted genetic selection. This review highlights many fruitful directions for research, aimed at the development of strategies for nutritional management of reproduction in the high-producing subfertile dairy cow.
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Review |
18 |
202 |
11
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Lien CL, Wu C, Mercer B, Webb R, Richardson JA, Olson EN. Control of early cardiac-specific transcription of Nkx2-5 by a GATA-dependent enhancer. Development 1999; 126:75-84. [PMID: 9834187 DOI: 10.1242/dev.126.1.75] [Citation(s) in RCA: 195] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The homeobox gene Nkx2-5 is the earliest known marker of the cardiac lineage in vertebrate embryos. Nkx2-5 expression is first detected in mesodermal cells specified to form heart at embryonic day 7.5 in the mouse and expression is maintained throughout the developing and adult heart. In addition to the heart, Nkx2-5 is transiently expressed in the developing pharynx, thyroid and stomach. To investigate the mechanisms that initiate cardiac transcription during embryogenesis, we analyzed the Nkx2-5 upstream region for regulatory elements sufficient to direct expression of a lacZ transgene in the developing heart of transgenic mice. We describe a cardiac enhancer, located about 9 kilobases upstream of the Nkx2-5 gene, that fully recapitulates the expression pattern of the endogenous gene in cardiogenic precursor cells from the onset of cardiac lineage specification and throughout the linear and looping heart tube. Thereafter, as the atrial and ventricular chambers become demarcated, enhancer activity becomes restricted to the developing right ventricle. Transcription of Nkx2-5 in pharynx, thyroid and stomach is controlled by regulatory elements separable from the cardiac enhancer. This distal cardiac enhancer contains a high-affinity binding site for the cardiac-restricted zinc finger transcription factor GATA4 that is essential for transcriptional activity. These results reveal a novel GATA-dependent mechanism for activation of Nkx2-5 transcription in the developing heart and indicate that regulation of Nkx2-5 is controlled in a modular manner, with multiple regulatory regions responding to distinct transcriptional networks in different compartments of the developing heart.
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26 |
195 |
12
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Neal DE, Ramsden PD, Sharples L, Smith A, Powell PH, Styles RA, Webb RJ. Outcome of elective prostatectomy. BMJ (CLINICAL RESEARCH ED.) 1989; 299:762-7. [PMID: 2508914 PMCID: PMC1837610 DOI: 10.1136/bmj.299.6702.762] [Citation(s) in RCA: 184] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
OBJECTIVES To determine the symptomatic and urodynamic outcome of elective prostatectomy and to establish whether the outcome is influenced or can be predicted by preoperative urodynamic measurements. DESIGN Prospective non-randomised study with follow up at a mean of 11 months after operation. Most men were assessed jointly by a urologist and a general practitioner. SETTING Department of urology in a teaching hospital serving a large district population. PATIENTS 253 Men listed for elective prostatectomy because of symptoms and low urinary flow rates (less than 15 ml/s) and excluding those already on a waiting list or with acute urinary retention, clinically apparent prostatic cancer, and neurological or cerebrovascular disease; 217 (86%) were followed up. INTERVENTION Elective prostatectomy. MAIN OUTCOME MEASURE Classification on the basis of relief of symptoms assessed by patients and urologist and general practitioner and of symptom scores obtained by questionnaire. RESULTS Of the 217 men followed up, 171 (79%) had a satisfactory subjective review and 155 (72%) had a satisfactory review and also low symptom scores. An unsatisfactory outcome was associated with preoperative symptoms of urge incontinence, small prostatic size and resected weight, low voiding pressures, and low urethral resistance. Preoperative maximum urinary flow rates did not predict outcome. Men with poor outcome could be classified into two groups: those with irritative symptoms who were more likely before operation to have had urge incontinence and detrusor instability and men with symptoms of poor urinary flow who were more likely before operation to have had a small prostate, low voiding pressures, and low urethral resistance. In patients in the second group flow rates or voiding pressures improved little after operation. Men with stable detrusors and either low urethral resistance or low voiding pressures were less likely to do well after prostatectomy, but despite these associations preoperative urodynamic measurements were unable to predict outcome accurately. CONCLUSIONS Prostatectomy was satisfactory in relieving symptoms and improving urodynamic measurements in most men, but even in those with classic symptoms and low urinary flow rates a substantial minority experienced little improvement afterwards and urodynamic measurements did not accurately predict outcome in individual patients.
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research-article |
36 |
184 |
13
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Hunter MG, Robinson RS, Mann GE, Webb R. Endocrine and paracrine control of follicular development and ovulation rate in farm species. Anim Reprod Sci 2004; 82-83:461-77. [PMID: 15271473 DOI: 10.1016/j.anireprosci.2004.05.013] [Citation(s) in RCA: 156] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Productivity in farm species is controlled by many factors, including ovulation rate. In cattle, single ovulations occur most frequently and in sheep (and goats) the number of ova released can range from one to many depending upon the breed, whilst the pig is polyovular. The processes of recruitment and selection determine the number of ovulatory follicles in all these species with FSH and subsequently LH playing major roles. GnRH-agonist models in which endogenous gonadotrophin secretion is suppressed and exogenous LH and/or FSH are administered at specific concentrations in defined patterns, are useful in all three species for elucidating the precise roles of specific hormones in stimulating follicular development. Differences in the hypothalamic-pituitary-ovarian feedback response lead to the differences in the number of ovulatory follicles, as does the pool of antral follicles from which the ovulatory ones are selected. Precocious development of follicles is also associated with more ovulations, as is the case with the Booroola due to the single gene acting through bone morphogenetic proteins (BMPs). It is well established that ovulation rate can also be influenced by exogenous hormone administration and by environmental factors such as nutrition. It has become apparent that these nuritional effects are mediated by a direct action at the level of the ovary, involving insulin, insulin-like growth factors (IGF) I and II and their binding proteins among other factors. These factors can also affect the quality of the oocyte and consequently embryo development and survival. Recently, the regulation of follicular angiogenesis has been shown to be important for the development of ovulatory follicles, particularly vascular endothelial growth factor (VEGF) which is produced primarily by the granulosa cells within the ovary and can be stimulated by gonadotrophins. Administration of VEGF has been shown to stimulate pre-antral follicular growth and increase the number of pre-ovulatory follicles. In summary both extra- and intra-ovarian factors are involved in the control of ovulation rate. Manipulation of the angiogenic process may also provide new opportunities for regulating the quality and number of follicles that ovulate.
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21 |
156 |
14
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Limpus CJ, Miller JD, Paramenter CJ, Reimer D, McLachlan N, Webb R. Migration of green (Chelonia mydas) and loggerhead (caretta caretta) turtles to and from eastern Australian rookeries. WILDLIFE RESEARCH 1992. [DOI: 10.1071/wr9920347] [Citation(s) in RCA: 150] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Feeding-ground captures of green (Chelonia mydas) and loggerhead (Caretta caretta) turtles tagged while
nesting at eastern Australian rookeries over a 21-year period are summarised.
These turtles which nest in the Great Barrier Reef region range widely throughout the Arafura and
Coral seas. The tag recoveries include many from turtles that live in neighbouring countries and migrate
to breed in Australia. The breeding female shows a high fidelity to her home feeding ground as well
as to her nesting beach. Most recaptures of the green turtles occurred during hunting for food by
indigenous people while most recaptures of loggerhead turtles were incidental captures in commercial
fishing activities. Migratory behaviour, imprinting and navigation are discussed.
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33 |
150 |
15
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Gong JG, Lee WJ, Garnsworthy PC, Webb R. Effect of dietary-induced increases in circulating insulin concentrations during the early postpartum period on reproductive function in dairy cows. Reproduction 2002. [DOI: 10.1530/rep.0.1230419] [Citation(s) in RCA: 149] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Although it has become increasingly clear that fertility in modern dairy cattle is declining in association with increased milk yields, the underlying mechanism is poorly understood. The first ovulation post partum is delayed in dairy cows undergoing selection for genetic merit for milk yield in association with lower circulating insulin concentrations. The aim of this study was to investigate whether feeding a diet to increase circulating insulin concentrations can overcome this delay in the first ovulation post partum. The experiment was a 2 x 2 factorial design (n = 10 per group) involving diet and genetic merit for milk yield. The dietary treatment started on the day of calving and lasted for 50 days. Plasma samples were collected each day and ovarian ultra-sonography was performed three times a week during the experimental feeding period. Milk yield was recorded each day, and body weight and body condition score were determined each week. Milk samples were collected three times a week from day 50 to day 105 post partum, and reproductive performance data were recorded for all the cows as part of the routine farm practice. The dietary treatment induced significant differences in plasma insulin concentrations in both high and low genetic merit cows. Although high genetic merit cows produced more milk, lost more body weight and had lower body condition scores during the experiment, no significant effect of diet was observed on these measurements. The high insulin inducing diet increased the proportion of cows ovulating within 50 days of calving and reduced the intervals from calving to first ovulation, and tended to reduce the intervals from calving to first service and to conception. These fertility parameters were also more favourable in low than in high genetic merit cows, but no interaction between diet and genetic merit was observed for any of these parameters. Genetic merit, but not diet, also affected the number of services required per conception and the conception rate. In conclusion, these results have confirmed that genetic selection for high milk yield is associated with a decrease in reproductive performance in dairy cows. More importantly, this study has demonstrated that it is possible to alleviate this problem by nutritional manipulation.
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23 |
149 |
16
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Armstrong DG, McEvoy TG, Baxter G, Robinson JJ, Hogg CO, Woad KJ, Webb R, Sinclair KD. Effect of Dietary Energy and Protein on Bovine Follicular Dynamics and Embryo Production In Vitro: Associations with the Ovarian Insulin-Like Growth Factor System1. Biol Reprod 2001; 64:1624-32. [PMID: 11369588 DOI: 10.1095/biolreprod64.6.1624] [Citation(s) in RCA: 140] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Heifers were assigned either low or high (HE) levels of energy intake and low or high concentrations of dietary crude protein. The effect of these diets on the plasma concentrations of insulin, insulin-like growth factor (IGF)-I, and urea on follicular growth and early embryo development is described. We propose that the observed dietary-induced changes in the ovarian IGF system increase bioavailability of intrafollicular IGF, thus increasing the sensitivity of follicles to FSH. These changes, in combination with increased peripheral concentrations of insulin and IGF-I in heifers offered the HE diet, contribute to the observed increase in growth rate of the dominant follicle. In contrast to follicular growth, increased nutrient supply decreased oocyte quality, due in part to increased plasma urea concentrations. Clearly a number of mechanisms are involved in mediating the effects of dietary energy and protein on ovarian function, and the formulation of diets designed to optimize cattle fertility must consider the divergent effects of nutrient supply on follicular growth and oocyte quality.
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24 |
140 |
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Lu J, Webb R, Richardson JA, Olson EN. MyoR: a muscle-restricted basic helix-loop-helix transcription factor that antagonizes the actions of MyoD. Proc Natl Acad Sci U S A 1999; 96:552-7. [PMID: 9892671 PMCID: PMC15174 DOI: 10.1073/pnas.96.2.552] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Skeletal muscle development is controlled by a family of muscle-specific basic helix-loop-helix (bHLH) transcription factors that activate muscle genes by binding E-boxes (CANNTG) as heterodimers with ubiquitous bHLH proteins, called E proteins. Myogenic bHLH factors are expressed in proliferating undifferentiated myoblasts, but they do not initiate myogenesis until myoblasts exit the cell cycle. We describe a bHLH protein, MyoR (for myogenic repressor), that is expressed in undifferentiated myoblasts in culture and is down-regulated during differentiation. MyoR is also expressed specifically in the skeletal muscle lineage between days 10.5 and 16.5 of mouse embryogenesis and down-regulated thereafter during the period of secondary myogenesis. MyoR forms heterodimers with E proteins that bind the same DNA sequence as myogenic bHLH/E protein heterodimers, but MyoR acts as a potent transcriptional repressor that blocks myogenesis and activation of E-box-dependent muscle genes. These results suggest a role for MyoR as a lineage-restricted transcriptional repressor of the muscle differentiation program.
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Hunt IM, Kapur N, Webb R, Robinson J, Burns J, Shaw J, Appleby L. Suicide in recently discharged psychiatric patients: a case-control study. Psychol Med 2009; 39:443-449. [PMID: 18507877 DOI: 10.1017/s0033291708003644] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND Few controlled studies have specifically investigated aspects of mental health care in relation to suicide risk among recently discharged psychiatric patients. We aimed to identify risk factors, including variation in healthcare received, for suicide within 3 months of discharge. METHOD We conducted a national population-based case-control study of 238 psychiatric patients dying by suicide within 3 months of hospital discharge, matched on date of discharge to 238 living controls. RESULTS Forty-three per cent of suicides occurred within a month of discharge, 47% of whom died before their first follow-up appointment. The first week and the first day after discharge were particular high-risk periods. Risk factors for suicide included a history of self-harm, a primary diagnosis of affective disorder, recent last contact with services and expressing clinical symptoms at last contact with staff. Suicide cases were more likely to have initiated their own discharge and to have missed their last appointment with services. Patients who were detained for compulsory treatment at last admission, or who were subject to enhanced levels of aftercare, were less likely to die by suicide. CONCLUSIONS The weeks after discharge from psychiatric care represent a critical period for suicide risk. Measures that could reduce risk include intensive and early community follow-up. Assessment of risk should include established risk factors as well as current mental state and there should be clear follow-up procedures for those who have self-discharged. Recent detention under the Mental Health Act and current use of enhanced levels of aftercare may be protective.
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Attanoos RL, Webb R, Dojcinov SD, Gibbs AR. Value of mesothelial and epithelial antibodies in distinguishing diffuse peritoneal mesothelioma in females from serous papillary carcinoma of the ovary and peritoneum. Histopathology 2002; 40:237-44. [PMID: 11895489 DOI: 10.1046/j.1365-2559.2002.01352.x] [Citation(s) in RCA: 132] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
AIMS To evaluate the role of mesothelial markers (calretinin, thrombomodulin, cytokeratin 5/6, and CD44H) and carcinoma markers (polyclonal and monoclonal carcinoembryonic antigen, Leu-M1, CA-125 and Ber-EP4) in distinguishing diffuse peritoneal malignant mesothelioma from primary serous papillary adenocarcinoma of the ovary and peritoneum. METHODS AND RESULTS Paraffin-embedded formalin-fixed blocks from 32 diffuse peritoneal mesotheliomas of epithelial subtype (all females), 20 serous papillary ovarian carcinomas and three primary peritoneal serous papillary carcinomas were studied. Calretinin and Ber-EP4 appeared to be the best positive mesothelial and carcinoma marker, respectively. Nuclear calretinin expression was identified in 28 of 32 malignant mesotheliomas with no nuclear immunoreactivity in the cohorts of serous papillary ovarian and peritoneal carcinomas, thus yielding 88% sensitivity and 100% specificity. Ber-EP4 showed 95% sensitivity and 91% specificity for serous papillary ovarian carcinoma. Thrombomodulin, cytokeratin 5/6 and CD44H immunoreactivities were seen in 18 (56%), 17 (53%) and 15 (47%) of peritoneal mesotheliomas, respectively, and in six (30%), five (25%) and five (25%) of the ovarian tumours, respectively. None of the three primary peritoneal serous papillary carcinomas expressed calretinin, thrombomodulin, cytokeratin 5/6 or CD44H. Polyclonal and monoclonal CEA, and Leu-M1 were expressed by two (10%), one (5%) and seven (35%) serous papillary ovarian carcinomas, respectively. None of the serous papillary peritoneal carcinomas expressed polyclonal CEA, monoclonal CEA or Leu-M1. CA-125 was positive in 19 (95%) and two (67%) ovarian and peritoneal carcinomas, respectively, and in eight (25%) peritoneal mesotheliomas. CONCLUSIONS Calretinin and Ber-EP4 are useful discriminant markers in distinguishing peritoneal mesothelioma in women from serous papillary ovarian and peritoneal carcinoma. The other mesothelial markers (thrombomodulin, cytokeratin 5/6, and CD44H) and carcinoma markers (polyclonal and monoclonal CEA, and Leu-M1) yielded a too low sensitivity for practical use.
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Adamiak SJ, Mackie K, Watt RG, Webb R, Sinclair KD. Impact of Nutrition on Oocyte Quality: Cumulative Effects of Body Composition and Diet Leading to Hyperinsulinemia in Cattle1. Biol Reprod 2005; 73:918-26. [PMID: 15972884 DOI: 10.1095/biolreprod.105.041483] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The present study sought to assess the combined effects of body composition and diet (level of feeding) on the postfertilization developmental potential of oocytes recovered from heifers using ultrasound-guided transvaginal follicular aspiration and to relate oocyte quality to the metabolic status of these animals. By collecting oocytes on repeated occasions spanning several weeks, it was possible to assess the cumulative effects of changes in nutritional status on oocyte quality over this period. Twenty-four heifers of low and moderate body condition were placed on one of two levels of feeding (equivalent to once or twice the maintenance requirements of these animals). Oocytes were recovered at two defined time points within each of three successive estrous cycles and were matured, fertilized, and cultured to the blastocyst stage in vitro. The results show that the effect of feeding level on oocyte quality is dependent on the body condition of the animal, with the high level of feeding being beneficial to oocytes from animals of low body condition but detrimental to oocytes from animals of moderately high body condition. Furthermore, the effects of high levels of feeding on oocyte quality were cumulative, with blastocyst yields for relatively fat heifers on twice the maintenance requirement deteriorating with time relative to yields for relatively thin heifers on the same level of feeding. Finally, a significant proportion of the moderately fat animals on the high level of feeding were hyperinsulinemic, and we show, to our knowledge for the first time in ruminants, that this condition is associated with impaired oocyte quality.
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Gong JG, Bramley T, Webb R. The effect of recombinant bovine somatotropin on ovarian function in heifers: follicular populations and peripheral hormones. Biol Reprod 1991; 45:941-9. [PMID: 1805998 DOI: 10.1095/biolreprod45.6.941] [Citation(s) in RCA: 125] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The objective of this study was to investigate the possible effect of recombinant bovine somatotropin (BST) on ovarian folliculogenesis and ovulation rate. Twelve Hereford x Friesian heifers received daily injections of either 25 mg BST (6 heifers) or vehicle (6 heifers) for a period of two estrous cycles until slaughter. Blood samples were collected three times a week for measurements of peripheral growth hormone (GH), insulin-like growth factor I (IGF-I), FSH, LH, estradiol, and progesterone. Serial blood samples were also taken every 10 min for 8 h on Days 12 and 19 of the second estrous cycle to monitor GH, IGF-I, FSH, and LH profiles. At the end of treatment (Day 7 of the third estrous cycle), the heifers were killed and their ovaries were collected. Ovulation rate was determined by counting the number of fresh corpora lutea (CL). All antral follicles greater than or equal to 2 mm in diameter were dissected to assess antral follicle populations. Granulosa and thecal cells from the three largest follicles and CL from each heifer were collected for FSH and LH binding measurements. All heifers had a single ovulation. The treated heifers had significantly more antral follicles (60.2 +/- 6.7) than did the animals in the control group (33.2 +/- 3.2) (p less than 0.001). When follicles were grouped according to diameter, the mean numbers of follicles greater than 10 mm, 5-10 mm, and 2-5 mm in diameter were 0.8 +/- 0.2, 6.8 +/- 1.4, and 52.5 +/- 6.5 for the treated group, and 0.8 +/- 0.2, 6.5 +/- 1.0, and 25.8 +/- 2.7 for controls.(ABSTRACT TRUNCATED AT 250 WORDS)
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Gong JG, Campbell BK, Bramley TA, Gutierrez CG, Peters AR, Webb R. Suppression in the secretion of follicle-stimulating hormone and luteinizing hormone, and ovarian follicle development in heifers continuously infused with a gonadotropin-releasing hormone agonist. Biol Reprod 1996; 55:68-74. [PMID: 8793060 DOI: 10.1095/biolreprod55.1.68] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
A novel experimental model was developed in cattle to investigate the requirement for FSH and LH during ovarian follicle growth and development. On Day 5 of the estrous cycle, 7 heifers were each implanted with an osmotic minipump containing a GnRH agonist (GnRHa), Buserelin (release rate, 2.5 micrograms/h). Another 7 heifers served as controls. Each minipump was replaced 28 days later with a second pump, which was left in place for a further 20 days. Blood samples were collected daily throughout the experimental period, and frequent samples were also collected on both days of minipump insertion and at 10 days after insertion of the second pump. The ovaries of all heifers were scanned daily by real-time ultrasonography to monitor follicular dynamics. All controls displayed 2 or 3 waves of FSH and follicular development per estrous cycle during the experiment. Insertion of the first minipump produced a large LH and FSH surge and induced ovulation in all 7 animals. Within 8 days of the start of treatment, serum LH concentrations fell to basal levels; they then remained constant at this level throughout the infusion period, only beginning to recover 4-5 days after the termination of infusion. After the initial increase, FSH returned to basal levels before showing a normal wave that was coincident with the emergence, growth, and regression of a dominant follicle. However, despite the peak levels of FSH, dominant follicles from the next wave failed to grow beyond 7-9 mm; they remained at this size for 3 wk until 3-4 days after insertion of the second minipump, when FSH fell precipitously to reach low levels that were maintained throughout the remainder of the infusion. After this fall in FSH concentrations, these follicles regressed rapidly, and no antral follicles > 4 mm were detected until after the termination of treatment. Thereafter, FSH concentrations increased significantly; the increase was accompanied by the emergence of a follicular wave and development of a dominant follicle, with estrus observed 8-11 days later. In conclusion, this study has demonstrated clearly that in cattle the early stages of follicle development (< or = 4 mm) are not dependent on acute support by gonadotropins. However, FSH is required for further growth of follicles up to 9 mm, while LH pulses are indispensable for follicle development beyond 9 mm in diameter. The model developed in this study should be valuable for studying the control of ovarian follicle development and atresia in vivo.
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Gosden RG, Boulton MI, Grant K, Webb R. Follicular development from ovarian xenografts in SCID mice. JOURNAL OF REPRODUCTION AND FERTILITY 1994; 101:619-23. [PMID: 7966017 DOI: 10.1530/jrf.0.1010619] [Citation(s) in RCA: 118] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Cortical slices of either cat or sheep ovaries were grafted under the renal capsules of ovariectomized SCID mice. The grafts became vascularized and were still surviving with large follicles present at autopsy up to nine months later. As developing follicles undergo atresia during the period of ischaemia after ovarian grafting, those found in long-term grafts at autopsy had presumably started to grow from the primordial stage after transplantation. Some follicles had reached a diameter of 3 mm with a normal antrum and appeared to be cytologically normal, but the latent period for the emergence of antral follicles was shorter in cat compared with sheep grafts. Oestradiol production from grafts, as indicated by vaginal cornification and plasma measurements collected at autopsy, was not constant and circulating concentrations varied among animals, and were sometimes far in excess of the normal physiological range of the host. The vaginal smears never presented cytological patterns like those of the normal mouse oestrous cycle, and ovulation had not occurred in any of the grafts. These results demonstrate that ovarian xenografts in SCID mice can serve as experimental models for investigating follicle development in species in which follicle growth in vitro and studies of the parent animal are impracticable.
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Penny LA, Armstrong D, Bramley TA, Webb R, Collins RA, Watson ED. Immune cells and cytokine production in the bovine corpus luteum throughout the oestrous cycle and after induced luteolysis. JOURNAL OF REPRODUCTION AND FERTILITY 1999; 115:87-96. [PMID: 10341726 DOI: 10.1530/jrf.0.1150087] [Citation(s) in RCA: 117] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Immune cells and their cytokine products have powerful local effects within body tissues. There has been great interest in the potential role of these cells, not only during destruction of the corpus luteum but also during its functional lifespan. In this study, lymphocytes, macrophages and major histocompatibility complex class II molecules were quantified using immunohistochemistry and the reverse transcription-polymerase chain reaction was used to detect mRNA for tumour necrosis factor alpha and interferon gamma within corpora lutea from three groups of cows: (1) corpora lutea collected at an abattoir and assessed visually into four stages (stage I (days 1-5), stage II (days 6-12), stage III (days 13-18) and stage IV (days 19-21) of the oestrous cycle); (2) corpora lutea collected around natural luteolysis (days 14-20); and (3) corpora lutea collected 6, 12 and 24 h after prostaglandin F 2 alpha-induced luteolysis. The numbers of T lymphocytes (CD5+ and CD8+) were significantly higher (P < 0.05) at stage IV and from day 16 onwards, before functional luteolysis. There were significantly higher numbers (P < 0.01) of macrophages at stages I, III and IV compared with stage II in visually staged tissue. Major histocompatibility complex class II molecules were increased (P < 0.05) at stages I and IV compared to stage II and at all times after induced luteolysis. Using reverse transcription-polymerase chain reaction, mRNA encoding tumour necrosis factor alpha and interferon gamma was detected in all luteal tissue collected around natural luteolysis and after induced luteolysis. These findings, particularly the increase in T lymphocytes before functional luteolysis, provide further evidence of a significant role for the immune system in affecting reproductive function in cows.
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Akerib DS, Araújo HM, Bai X, Bailey AJ, Balajthy J, Bedikian S, Bernard E, Bernstein A, Bolozdynya A, Bradley A, Byram D, Cahn SB, Carmona-Benitez MC, Chan C, Chapman JJ, Chiller AA, Chiller C, Clark K, Coffey T, Currie A, Curioni A, Dazeley S, de Viveiros L, Dobi A, Dobson J, Dragowsky EM, Druszkiewicz E, Edwards B, Faham CH, Fiorucci S, Flores C, Gaitskell RJ, Gehman VM, Ghag C, Gibson KR, Gilchriese MGD, Hall C, Hanhardt M, Hertel SA, Horn M, Huang DQ, Ihm M, Jacobsen RG, Kastens L, Kazkaz K, Knoche R, Kyre S, Lander R, Larsen NA, Lee C, Leonard DS, Lesko KT, Lindote A, Lopes MI, Lyashenko A, Malling DC, Mannino R, McKinsey DN, Mei DM, Mock J, Moongweluwan M, Morad J, Morii M, Murphy ASJ, Nehrkorn C, Nelson H, Neves F, Nikkel JA, Ott RA, Pangilinan M, Parker PD, Pease EK, Pech K, Phelps P, Reichhart L, Shutt T, Silva C, Skulski W, Sofka CJ, Solovov VN, Sorensen P, Stiegler T, O'Sullivan K, Sumner TJ, Svoboda R, Sweany M, Szydagis M, Taylor D, Tennyson B, Tiedt DR, Tripathi M, Uvarov S, Verbus JR, Walsh N, Webb R, White JT, White D, Witherell MS, Wlasenko M, Wolfs FLH, et alAkerib DS, Araújo HM, Bai X, Bailey AJ, Balajthy J, Bedikian S, Bernard E, Bernstein A, Bolozdynya A, Bradley A, Byram D, Cahn SB, Carmona-Benitez MC, Chan C, Chapman JJ, Chiller AA, Chiller C, Clark K, Coffey T, Currie A, Curioni A, Dazeley S, de Viveiros L, Dobi A, Dobson J, Dragowsky EM, Druszkiewicz E, Edwards B, Faham CH, Fiorucci S, Flores C, Gaitskell RJ, Gehman VM, Ghag C, Gibson KR, Gilchriese MGD, Hall C, Hanhardt M, Hertel SA, Horn M, Huang DQ, Ihm M, Jacobsen RG, Kastens L, Kazkaz K, Knoche R, Kyre S, Lander R, Larsen NA, Lee C, Leonard DS, Lesko KT, Lindote A, Lopes MI, Lyashenko A, Malling DC, Mannino R, McKinsey DN, Mei DM, Mock J, Moongweluwan M, Morad J, Morii M, Murphy ASJ, Nehrkorn C, Nelson H, Neves F, Nikkel JA, Ott RA, Pangilinan M, Parker PD, Pease EK, Pech K, Phelps P, Reichhart L, Shutt T, Silva C, Skulski W, Sofka CJ, Solovov VN, Sorensen P, Stiegler T, O'Sullivan K, Sumner TJ, Svoboda R, Sweany M, Szydagis M, Taylor D, Tennyson B, Tiedt DR, Tripathi M, Uvarov S, Verbus JR, Walsh N, Webb R, White JT, White D, Witherell MS, Wlasenko M, Wolfs FLH, Woods M, Zhang C. First results from the LUX dark matter experiment at the Sanford underground research facility. PHYSICAL REVIEW LETTERS 2014; 112:091303. [PMID: 24655239 DOI: 10.1103/physrevlett.112.091303] [Show More Authors] [Citation(s) in RCA: 116] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2013] [Indexed: 06/03/2023]
Abstract
The Large Underground Xenon (LUX) experiment is a dual-phase xenon time-projection chamber operating at the Sanford Underground Research Facility (Lead, South Dakota). The LUX cryostat was filled for the first time in the underground laboratory in February 2013. We report results of the first WIMP search data set, taken during the period from April to August 2013, presenting the analysis of 85.3 live days of data with a fiducial volume of 118 kg. A profile-likelihood analysis technique shows our data to be consistent with the background-only hypothesis, allowing 90% confidence limits to be set on spin-independent WIMP-nucleon elastic scattering with a minimum upper limit on the cross section of 7.6 × 10(-46) cm(2) at a WIMP mass of 33 GeV/c(2). We find that the LUX data are in disagreement with low-mass WIMP signal interpretations of the results from several recent direct detection experiments.
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