Martin Sheldon

Last updated

Martin Sheldon is a veterinarian and scientific researcher. He is Professor in Reproductive Immunobiology [1] at Swansea University Medical School. [2]

Contents

Career

Born in Yorkshire, Sheldon studied at Bradford Grammar School and then at the University of Liverpool School of Veterinary Science. He graduated with a Bachelor of Veterinary Science and membership of the Royal College of Veterinary Surgeons in 1984. He spent 14 years in clinical veterinary practice in Carmarthen, West Wales, where he became a partner in 1986. Sheldon was awarded the Diploma in Bovine Reproduction from the University of Liverpool in 1992; became a Royal College of Veterinary Surgeons Specialist in 1993; [3] and, was awarded the Diploma in Cattle Health and Production from the Royal College of Veterinary Surgeons in 1997. [4]

Sheldon joined the Royal Veterinary College in 1998 to teach veterinary reproduction, and he was awarded the James Bee Educator Prize twice. He completed a PhD with Professor Hilary Dobson in 2002 through the University of Liverpool. Research project funding from the Wellcome Trust and Biotechnology and Biological Sciences Research Council (BBSRC) formed the foundation for his research. Whilst in London, Sheldon spent some time on an OECD fellowship at the Cornell University College of Veterinary Medicine, USA; as a visiting lecturer at the University of Bologna, Italy; and, on the Frontiers in Reproduction Course at the Marine Biological Laboratory, Woods Hole, USA. In 2006, Sheldon was awarded a 3-year BBSRC Research Development Fellowship [5] and in 2008 he moved from London to a new Personal Chair at the Institute of Life Science in Swansea University Medical School. [6] In 2013, Sheldon was a Distinguished Lecturer at the University of Florida. Sheldon has published more than 100 papers in academic journals; [7] and is on the editorial board of the American Journal of Reproductive Immunology. [8]

Sheldon works on infection and immunity. [1] His initial work was on bacterial infection of the female reproductive system, particularly postpartum metritis. [9] Using dairy cattle, he identified the bacteria that cause uterine disease, including novel strains of Escherichia coli that are adapted to the uterine environment. [10] In addition, Sheldon showed that the bacterium Trueperella pyogenes becomes a pathogen in the uterus by secreting a cholesterol-dependent cytolysin that damages stromal cells, once the epithelium is damaged after parturition. [11] Oxysterols, such as 25-hydroxycholesterol, are found in the reproductive tract and protect tissue cells against cholesterol-dependent cytolysins. [12] Sheldon uncovered the role for the innate immune system in the endometrium of the uterus, showing that epithelial and stromal cells, as well as the expected immune cells, have roles in host-pathogen interactions. [13] Sheldon was the first to show that infections in the uterus disrupt the structure and function of the mammalian ovary. [14] Sheldon also identified that ovarian cells sense and respond to pathogen-associated molecular patterns, leading to inflammation, and even damaging the oocyte. [15] Work on cholesterol-dependent cytolysins has led to discoveries about how host tissue cells can be protected against toxins. [16] [17]

Distinctions

Fellowship Royal College of Veterinary Surgeons (2013) for meritorious contributions to understanding the mechanisms of infection and immunity in the female genital tract [18]

Schofield Medal: a prize given in honor of Frank Schofield, by Ontario Veterinary College, Canada (2015) [19]

Related Research Articles

Dilationand curettage (D&C) refers to the dilation of the cervix and surgical removal of part of the lining of the uterus or contents of the uterus by scraping and scooping (curettage). It is a gynecologic procedure used for diagnostic and therapeutic purposes, and is the most commonly used method for first-trimester miscarriage or abortion.

<span class="mw-page-title-main">Endometrium</span> Inner mucous membrane of the mammalian uterus

The endometrium is the inner epithelial layer, along with its mucous membrane, of the mammalian uterus. It has a basal layer and a functional layer: the basal layer contains stem cells which regenerate the functional layer. The functional layer thickens and then is shed during menstruation in humans and some other mammals, including apes, Old World monkeys, some species of bat, the elephant shrew and the Cairo spiny mouse. In most other mammals, the endometrium is reabsorbed in the estrous cycle. During pregnancy, the glands and blood vessels in the endometrium further increase in size and number. Vascular spaces fuse and become interconnected, forming the placenta, which supplies oxygen and nutrition to the embryo and fetus. The speculated presence of an endometrial microbiota has been argued against.

<span class="mw-page-title-main">Uterus</span> Female sex organ in mammals

The uterus or womb is the organ in the reproductive system of most female mammals, including humans, that accommodates the embryonic and fetal development of one or more embryos until birth. The uterus is a hormone-responsive sex organ that contains glands in its lining that secrete uterine milk for embryonic nourishment.

<span class="mw-page-title-main">Exotoxin</span> Toxin from bacteria that destroys or disrupts cells

An exotoxin is a toxin secreted by bacteria. An exotoxin can cause damage to the host by destroying cells or disrupting normal cellular metabolism. They are highly potent and can cause major damage to the host. Exotoxins may be secreted, or, similar to endotoxins, may be released during lysis of the cell. Gram negative pathogens may secrete outer membrane vesicles containing lipopolysaccharide endotoxin and some virulence proteins in the bounding membrane along with some other toxins as intra-vesicular contents, thus adding a previously unforeseen dimension to the well-known eukaryote process of membrane vesicle trafficking, which is quite active at the host–pathogen interface.

<span class="mw-page-title-main">Pyometra</span> Medical condition

Pyometra or pyometritis is a uterine infection. Though it is most commonly known as a disease of the unaltered female dog, it is also a notable human disease. It is also seen in female cattle, horses, goats, sheep, swine, cats, rabbits, hamsters, ferrets, rats and guinea pigs. Pyometra is an important disease to be aware of for any dog or cat owner because of the sudden nature of the disease and the deadly consequences if left untreated. It has been compared to acute appendicitis in humans, because both are essentially empyemas within an abdominal organ.

<span class="mw-page-title-main">Adenomyosis</span> Extension of endometrial tissue into the myometrium

Adenomyosis is a medical condition characterized by the growth of cells that proliferate on the inside of the uterus (endometrium) atypically located among the cells of the uterine wall (myometrium), as a result, thickening of the uterus occurs. As well as being misplaced in patients with this condition, endometrial tissue is completely functional. The tissue thickens, sheds and bleeds during every menstrual cycle.

<span class="mw-page-title-main">Vaginal bleeding</span> Medical condition

Vaginal bleeding is any expulsion of blood from the vagina. This bleeding may originate from the uterus, vaginal wall, or cervix. Generally, it is either part of a normal menstrual cycle or is caused by hormonal or other problems of the reproductive system, such as abnormal uterine bleeding.

<span class="mw-page-title-main">Hysteroscopy</span> Medical procedure

Hysteroscopy is the inspection of the uterine cavity by endoscopy with access through the cervix. It allows for the diagnosis of intrauterine pathology and serves as a method for surgical intervention.

<span class="mw-page-title-main">Endometritis</span> Medical condition

Endometritis is inflammation of the inner lining of the uterus (endometrium). Symptoms may include fever, lower abdominal pain, and abnormal vaginal bleeding or discharge. It is the most common cause of infection after childbirth. It is also part of spectrum of diseases that make up pelvic inflammatory disease.

<i>Campylobacter fetus</i> Species of bacterium

Campylobacter fetus is a rod-shaped, gram-negative species of bacteria within the genus Campylobacter of phylum Pseudomonadota. Identification of C. fetus species in infected animals or people is routinely performed by culture on blood or cefoperazone deoxycholate agar. Subspecies of C. fetus commonly causes reproductive disease in ruminants and gastrointestinal disease in humans. Transmission of C. fetus subspecies venerealis occurs mainly through venereal contact while transmission of C. fetus subspecies fetus occurs mainly through ingestion of bacteria in a contaminated environment. Infertility in cattle and abortion in sheep are common outcomes of infection associated with C. fetus subspecies venerealis and C. fetus subspecies fetus, respectively. Disease in humans occurs through zoonotic transmission of C. fetus mainly via ingestion of contaminated food or water sources. C. fetus can be diagnosed with polymerase chain reaction assays, enzyme linked immunosorbent assays and vaginal mucus agglutination testing. As vaccines are typically not efficient in preventing future spread, infected bulls are often culled. Human infections may be treated with erythromycin as antimicrobial resistance has been emerging for the fluoroquinolones.

Bovine alphaherpesvirus 1 (BoHV-1) is a virus of the family Herpesviridae and the subfamily Alphaherpesvirinae, known to cause several diseases worldwide in cattle, including rhinotracheitis, vaginitis, balanoposthitis, abortion, conjunctivitis, and enteritis. BoHV-1 is also a contributing factor in shipping fever, also known as bovine respiratory disease (BRD). It is spread horizontally through sexual contact, artificial insemination, and aerosol transmission and it may also be transmitted vertically across the placenta. BoHV-1 can cause both clinical and subclinical infections, depending on the virulence of the strain. Although these symptoms are mainly non-life-threatening it is an economically important disease as infection may cause a drop in production and affect trade restrictions. Like other herpesviruses, BoHV-1 causes a lifelong latent infection and sporadic shedding of the virus. The sciatic nerve and trigeminal nerve are the sites of latency. A reactivated latent carrier is normally the source of infection in a herd. The clinical signs displayed are dependent on the virulence of the strain. There is a vaccine available which reduces the severity and incidence of disease. Some countries in Europe have successfully eradicated the disease by applying a strict culling policy.

<span class="mw-page-title-main">Bovine viral diarrhea</span> Significant economic disease of cattle caused by two species of Pestivirus

Bovine viral diarrhea (BVD), bovine viral diarrhoea or mucosal disease, previously referred to as bovine virus diarrhea (BVD), is an economically significant disease of cattle that is found in the majority of countries throughout the world. Worldwide reviews of the economically assessed production losses and intervention programs incurred by BVD infection have been published. The causative agent, bovine viral diarrhea virus (BVDV), is a member of the genus Pestivirus of the family Flaviviridae.

<span class="mw-page-title-main">Implantation (embryology)</span> First stage of pregnancy

Implantation, also known as nidation, is the stage in the embryonic development of mammals in which the blastocyst hatches, attaches, adheres, and invades into the wall of the female's uterus. Implantation is the first stage of gestation, and, when successful, the female is considered to be pregnant. An implanted embryo is detected by the presence of increased levels of human chorionic gonadotropin (hCG) in a pregnancy test. The implanted embryo will receive oxygen and nutrients in order to grow.

Streptolysins are two hemolytic exotoxins from Streptococcus pyogenes. Types include streptolysin O, which is oxygen-labile, and streptolysin S, which is oxygen-stable.

<span class="mw-page-title-main">Metritis</span> Inflammation of the wall of the uterus

Metritis is inflammation of the wall of the uterus, whereas endometritis is inflammation of the functional lining of the uterus, called the endometrium. The term pelvic inflammatory disease (PID) is often used for metritis.

Uterine serpins are members of the A clade of the serine protease inhibitor (serpin) superfamily of proteins and are encoded by the SERPINA14 gene. Uterine serpins are produced by the endometrium of a restricted group of mammals under the influence of progesterone or estrogen. These proteins appear to be inactive protease inhibitors and may function during pregnancy to regulate immune function or participate in transplacental transport.

Menstruation is the shedding of the uterine lining (endometrium). It occurs on a regular basis in uninseminated sexually reproductive-age females of certain mammal species.

<span class="mw-page-title-main">Uterine microbiome</span>

The uterine microbiome is the commensal, nonpathogenic, bacteria, viruses, yeasts/fungi present in a healthy uterus, amniotic fluid and endometrium and the specific environment which they inhabit. It has been only recently confirmed that the uterus and its tissues are not sterile. Due to improved 16S rRNA gene sequencing techniques, detection of bacteria that are present in low numbers is possible. Using this procedure that allows the detection of bacteria that cannot be cultured outside the body, studies of microbiota present in the uterus are expected to increase.

<span class="mw-page-title-main">Preimplantation factor</span> Peptide involved in placental development

Preimplantation factor(PIF) is a peptide secreted by trophoblast cells prior to placenta formation in early embryonic development. Human embryos begin to express PIF at the 4-cell stage, with expression increasing by the morula stage and continuing to do so throughout the first trimester. Expression of preimplantation factor in the blastocyst was discovered as an early correlate of the viability of the eventual pregnancy. Preimplantation factor was identified in 1994 by a lymphocyte platelet-binding assay, where it was thought to be an early biomarker of pregnancy. It has a simple primary structure with a short sequence of fifteen amino acids without any known quaternary structure. A synthetic analogue of preimplantation factor (commonly abbreviated in studies as sPIF or PIF*) that has an identical amino acid sequence and mimics the normal biological activity of PIF has been developed and is commonly used in research studies, particularly those that aim to study potential adult therapeutics.

<span class="mw-page-title-main">Bovine vaginal prolapse</span>

Bovine vaginal prolapse is a medical condition in cattle, characterised by an abnormally positioned (prolapsed) vagina. In most cases the bovine vaginal prolapse occurs near the time of calving, yet there are some examples of the vaginal prolapse in younger and non-pregnant animals. Another, but less common and more severe reproductive prolapse in cattle is so-called bovine uterine prolapse, where a uterus is the one being abnormally positioned.

References

  1. 1 2 "Professor Martin Sheldon". sites.google.com. Retrieved 11 November 2019.
  2. ↑ "Professor Martin Sheldon". www.swansea.ac.uk. Retrieved 27 May 2017.
  3. ↑ "2013 AMCB Distinquished[sic] Lecturer: Martin Sheldon" (PDF). Animal Molecular and Cellular Biology Graduate Program. Eleventh Annual Research Symposium. University of Florida.
  4. ↑ "Biography - Professor Martin Sheldon - Swansea University". sites.google.com. Retrieved 13 December 2019.
  5. ↑ "Annual Report 2005-06" (PDF). Royal Veterinary College, London.
  6. ↑ "Speakers' biographies". European Society for Reproductive Immunology. Retrieved 27 May 2017.
  7. ↑ "I Martin Sheldon FRCVS - Google Scholar Citations". scholar.google.co.uk. Retrieved 27 May 2017.
  8. ↑ American Journal of Reproductive Immunology - Editorial Board - Wiley Online Library
  9. ↑ Sheldon IM, Cronin J, Goetze L, Donofrio G, Schuberth HJ (December 2009). "Defining postpartum uterine disease and the mechanisms of infection and immunity in the female reproductive tract in cattle". Biology of Reproduction. 81 (6): 1025–32. doi:10.1095/biolreprod.109.077370. PMC   2784443 . PMID   19439727.
  10. ↑ Sheldon IM, Rycroft AN, Dogan B, Craven M, Bromfield JJ, Chandler A, et al. (February 2010). "Specific strains of Escherichia coli are pathogenic for the endometrium of cattle and cause pelvic inflammatory disease in cattle and mice". PLOS ONE. 5 (2): e9192. Bibcode:2010PLoSO...5.9192S. doi: 10.1371/journal.pone.0009192 . PMC   2820550 . PMID   20169203.
  11. ↑ Amos MR, Healey GD, Goldstone RJ, Mahan SM, Düvel A, Schuberth HJ, Sandra O, Zieger P, Dieuzy-Labaye I, Smith DG, Sheldon IM (March 2014). "Differential endometrial cell sensitivity to a cholesterol-dependent cytolysin links Trueperella pyogenes to uterine disease in cattle". Biology of Reproduction. 90 (3): 54. doi: 10.1095/biolreprod.113.115972 . PMID   24478394.
  12. ↑ Ormsby TJ, Owens SE, Horlock AD, Davies D, Griffiths WJ, Wang Y, Cronin JG, Bromfield JJ, Sheldon IM (October 2021). "Oxysterols protect bovine endometrial cells against pore-forming toxins from pathogenic bacteria". FASEB Journal. 35 (10): e21889. doi: 10.1096/fj.202100036R . PMC   9272411 . PMID   34569656.
  13. ↑ WalesOnline (22 September 2010). "Welsh success in battle to stop causes of infertility". walesonline. Retrieved 27 May 2017.
  14. ↑ Sheldon IM, Noakes DE, Rycroft AN, Pfeiffer DU, Dobson H (June 2002). "Influence of uterine bacterial contamination after parturition on ovarian dominant follicle selection and follicle growth and function in cattle". Reproduction. 123 (6): 837–45. doi: 10.1530/rep.0.1230837 . PMID   12052238.
  15. ↑ Price JC, Bromfield JJ, Sheldon IM (September 2013). "Pathogen-associated molecular patterns initiate inflammation and perturb the endocrine function of bovine granulosa cells from ovarian dominant follicles via TLR2 and TLR4 pathways". Endocrinology. 154 (9): 3377–86. doi: 10.1210/en.2013-1102 . PMID   23825132.
  16. ↑ Preta G, Lotti V, Cronin JG, Sheldon IM (April 2015). "Protective role of the dynamin inhibitor Dynasore against the cholesterol-dependent cytolysin of Trueperella pyogenes". FASEB Journal. 29 (4): 1516–28. doi: 10.1096/fj.14-265207 . PMC   4396600 . PMID   25550455.
  17. ↑ Griffin S, Healey GD, Sheldon IM (October 2018). "Isoprenoids increase bovine endometrial stromal cell tolerance to the cholesterol-dependent cytolysin from Trueperella pyogenes". Biology of Reproduction. 99 (4): 749–760. doi:10.1093/biolre/ioy099. PMC   6203874 . PMID   29688258.
  18. ↑ "Celebration and change at RCVS Day 2013". RCVS. Retrieved 27 May 2017.
  19. ↑ "Iamnews.co.uk".
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.