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L Wilton

Publications and source records attributed to L Wilton.

At least 19 recordsLinked to original sources
PubMed2006

Human embryo: a biological definition.

This paper defines a human embryo from a biological standpoint that takes into account emerging technologies in reproductive science. The paper does not consider legal, moral, religious or social views. As the definition of a human embryo must reflect the multifactorial processes of development, an approach has been adopted which combines recognition of observed events with potential for further development. This acknowledges that fertilization and development are not static processes, and as such embryo status can only be defined by observation of specific markers. The following biological definition of 'human embryo' is proposed. A human embryo is a discrete entity that has arisen from either: the first mitotic division when fertilization of a human oocyte by a human sperm is complete or any other process that initiates organized development of a biological entity with a human nuclear genome or altered human nuclear genome that has the potential to develop up to, or beyond, the stage at which the primitive streak appears, and has not yet reached 8 weeks of development since the first mitotic division.

Beginning of Human Life↗
PubMed2006

ESHRE PGD Consortium data collection VI: cycles from January to December 2003 with pregnancy follow-up to October 2004.

The sixth report of the ESHRE PGD Consortium is presented, relating to cycles collected for the calendar year 2003 and follow-up of the pregnancies and babies born up to October 2004. Since the beginning of the data collections, there has been a steady rise in the number of cycles, pregnancies and babies reported. For this report, 50 centres participated, reporting on 2984 cycles, 501 pregnancies and 373 babies born. Five hundred and twenty-nine cycles were reported for chromosomal abnormalities, 516 cycles were reported for monogenic diseases, 137 cycles were reported for sexing for X-linked diseases, 1722 cycles were reported for preimplantation genetic screening (PGS) and 80 cycles were reported for social sexing. Data VI is compared to the cumulative data for data collections I-V.

Abortion, Spontaneous↗
PubMed2006

Safety profile of repaglinide as used in general practice in England: results of a prescription-event monitoring study.

Repaglinide is a prandial glucose regulator indicated for management of type 2 diabetes. This post-marketing study used the observational cohort technique of prescription-event monitoring (PEM) to monitor safety of repaglinide prescribed in primary care in England. Patients were identified from dispensed prescriptions issued by general practitioners (GPs) between December 1998 and January 2001. Demographic and clinical event data were collected from questionnaires posted to GPs at least six months after the date of first prescription for each patient. The cohort consisted of 5731 patients [median age 60 (IQR 51-68), 49.9% male]. Event incidence densities (IDs) [no. 1st reports/1000 patient-months of exposure] were calculated for all events reported. The most frequently recorded clinical events in the first month were diarrhoea (ID(1) 10.3), malaise/lassitude (ID(1) 8.1) and nausea/vomiting (ID(1) 7.9). The most frequently reported reason for stopping was 'not effective' (647), with the most common clinical reasons being diarrhoea (60), malaise/lassitude (55) and intolerance (54). One hundred and thirteen adverse drug reactions (ADRs) were reported, with the most frequently specified being diarrhoea (10), abdominal pain (10) and nausea/vomiting (9). We concluded that repaglinide is generally well tolerated when used in general practice in England and did not identify any serious unrecognised adverse events.

Aged↗
PubMed2005

ESHRE PGD Consortium data collection V: cycles from January to December 2002 with pregnancy follow-up to October 2003.

The fifth report of the ESHRE PGD Consortium is presented (data collection V). For the first time, the cycle data were collected for one calendar year (2002) in the following October, so that data collection was complete for pregnancies and babies. The data were collected using a Filemaker Pro database and divided into referrals, cycles, pregnancies and babies. There are currently 66 active centres registered with the consortium; however, the data presented here were obtained from 43 centres and included 1603 referrals, 2219 cycles, 485 pregnancies and 382 babies born. The cycle data were divided into preimplantation genetic diagnosis (PGD) for inherited disorders (including chromosome abnormalities, sexing for X-linked disease and monogenic disorders), aneuploidy screening (PGS) and the use of PGD for social sexing. Data collection V is compared with the previous cumulative data collection (I-IV), which comprised 4058 PGD/PGS cycles that reached oocyte retrieval.

Aneuploidy↗
PubMed2004

ESHRE PGD Consortium data collection IV: May-December 2001.

The ESHRE PGD Consortium was formed in 1997 to survey the practice of preimplantation genetic diagnosis (PGD). Since then, three reports have been published giving an overview on PGD from an ever-increasing number of centres and reporting on an increasing number of PGD cycles and pregnancies and babies born after PGD. After these initial influential publications, important shortcomings were identified primarily on the method of data collection, i.e. with Excel spreadsheets, and in the timing of the collection (cycles were collected in a different time frame from pregnancies and babies, making the follow-up of cycles very difficult). This is why the Steering Committee has made a major investment in developing and implementing a new database in FileMaker Pro 6. It was also decided that cycles would be collected from one calendar year, as well as the pregnancies and babies ensuing from that particular calendar year. This gave us the opportunity to take a closer look at the data collected earlier, and to attempt to improve their quality. This is a report on the corrected data from the first three data collections (I-III) as well as the result of the last data collection (IV) that was completely carried out using the new database.

Data Collection↗
PubMed2004

ESHRE PGD Consortium 'Best practice guidelines for clinical preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS)'.

Among the many educational materials produced by the European Society of Human Reproduction and Embryology (ESHRE) are guidelines. ESHRE guidelines may be developed for many reasons but their intent is always to promote best quality practices in reproductive medicine. In an era in which preimplantation genetic diagnosis (PGD) has become a reality, we must strive to maintain its efficacy and credibility by offering the safest and most effective treatment available. The dominant motivators for the development of current comprehensive guidelines for best PGD practice were (i) the absence of guidelines and/or regulation for PGD in many countries and (ii) the observation that no consensus exists on many of the clinical and technical aspects of PGD. As a consequence, the ESHRE PGD Consortium undertook to draw up guidelines aimed at giving information, support and guidance to potential, fledgling and established PGD centres. The success of a PGD treatment cycle is the result of great attention to detail. We have strived to provide a similar level of detail in this document and hope that it will assist staff in achieving the best clinical outcome for their patients.

Biopsy↗
PubMed2004

Survival and developmental potential of stored human early cleavage stage embryos.

Human early cleavage stage embryos which survive cryopreservation and thawing fully intact demonstrate similar developmental potential to equivalent non frozen embryos when returned to the in vivo environment, whereas blastomere loss is directly related to the loss of potential for subsequent implantation in thawed embryos. This suggests that blastomere lysis during freezing and thawing does not occur preferentially in non viable blastomeres. Prefreeze growth rate rather than prefreeze blastomere number per se correlates with the developmental potential of stored embryos. When blastomere loss occurs as a consequence of cryopreservation, development of thawed early cleavage stage embryos to the blastocyst stage in vitro is impaired and the resultant blastocysts have a reduced total cell content. Blastomere loss is more prevalent in embryos which have been biopsied for preimplantation genetic diagnosis but this increased sensitivity can be circumvented by modification of the standard cryopreservation protocol.

Blastomeres↗
PubMed2002

The Audit Commission review of diabetes services in England and Wales, 1998-2001.

UNLABELLED: AIMS OF THE AUDIT COMMISSION: The Audit Commission has a statutory duty to promote the best use of public money. It does this through value for money studies, such as that reported in Testing Times[1]. This work has been followed with a review of innovative practice in commissioning. These initiatives aim to support the implementation of the diabetes national service framework. The Audit Commission also appoints external auditors to NHS organizations who assess probity and value for money in the NHS; the latter by applying national studies locally and by carrying out local studies. METHODS: Research for Testing Times consisted of structured visits to nine acute trusts, a telephone survey of 26 health authorities and a postal survey of 1400 people with diabetes and 250 general practitioners. Local audits used a subset of the original research tools. Case studies were identified through a cascade approach to contacts established during Testing Times and through self-nomination. RESULTS: Rising numbers of people with diabetes are placing increasing pressure on hospital services. Some health authorities and primary care organizations have reviewed patterns of service provision in the light of the increasing demands. These reviews show wide variations in patterns of routine care. In addition, there is a widespread lack of data on the delivery of structured care to people with diabetes. People with diabetes report delays in gaining access to services, and insufficient time with staff. There are insufficient arrangements in place for providing information and learning opportunities to support self-management. CONCLUSION: As the number of people with diabetes continues to rise, the potential for providing more care in a primary care setting needs to be explored. This will enable specialist services to focus more effectively on those with the most complex needs.

Diabetes Mellitus↗
PubMed2002

Chromosome abnormalities identified by comparative genomic hybridization in embryos from women with repeated implantation failure.

Using comparative genomic hybridization, we have detected chromosome abnormality in 76/126 (60%) single blastomeres biopsied prior to implantation from embryos from 20 women with repeated implantation failure following IVF. The abnormalities detected included aneuploidy for one or two chromosomes [32/126 (25%)] and complex chromosomal abnormality [37/126 (29%)]. Most of the chromosomes involved in single aneuploidy were those commonly found in live births or spontaneously aborted fetuses, whereas a greater range of chromosomes were involved in double aneuploidy. In blastomeres with complex abnormality, random and extensive loss and gain of all the chromosomes was observed. Further blastomeres from 25 embryos with single or double aneuploidy and 11 embryos with complex abnormality were analysed following embryo disaggregation. The specific abnormality was confirmed in the majority of cases and in some cases could be assigned as errors in meiotic or mitotic segregation. Complex abnormalities, suggestive of errors in cell cycle regulation, were present in a slightly higher proportion of these embryos than were seen in our previously studied cohort of surplus embryos. The disruption of the normal sequence of chromosome replication and segregation in early human embryos, caused either by maternal cytoplasmic factors or mutations in cell cycle control genes, may be a common cause of repeated implantation failure.

Adult↗
PubMed2000

Chromosome analysis of blastomeres from human embryos by using comparative genomic hybridization.

Karyotypic studies of aborted fetuses have been used to draw the inference that the proportion of conceptuses with chromosome abnormalities is very high. Fluorescent in situ hybridization (FISH) studies of blastomeres from early cleavage embryos have provided some support for this inference but they are limited to the study of a few chromosomes. We describe the novel application of comparative genomic hybridization (CGH) to the study of numerical and structural abnormalities of single blastomeres from disaggregated 3-day-old human embryos. CGH results were obtained for 63 blastomeres from 12 embryos. Identification of all chromosomes with the exception of chromosomes 17, 19, 20 and 22 was possible. The embryos divided into four groups: (1) embryos with a normal CGH karyotype seen in all blastomeres; (2) embryos with consistent aneuploidy suggesting meiotic non-disjunction had occurred; (3) embryos that were mosaic generally with one or more cells showing aneuploidy for one or two chromosomes but some with cells showing extensive aneuploidy; and (4) one embryo with extensive aneuploidy in all blastomeres. The extensive aneuploidy in group 4 is interpreted as corresponding to the random aneuploidy seen in "chaotic" embryos reported by using interphase FISH. Partial chromosome loss and gain following chromosome breakage was observed in one embryo. Our analysis provides basic biological information on the occurrence of constitutional and post-zygotic chromosome abnormalities in early human embryos. Used in conjunction with embryo biopsy, diagnostic CGH should allow the exclusion of a proportion of embryos that appear normal but that have a poor probability of survival and, therefore, may improve the implantation rate after in vitro fertilization.

Base Sequence↗
PubMed2000

The pharmacovigilance of tamsulosin: event data on 12484 patients.

OBJECTIVE: To determine drug effectiveness and adverse effects in a noninterventional observational cohort study of over 10 000 patients treated with tamsulosin in general medical practice. METHODS: Using prescription-event monitoring, data were collected of all prescriptions for tamsulosin issued nationally during June 1996 to January 1998. For each patient entered into the cohort a computerized longitudinal record of exposure was constructed. The outcome data, patient information and an opinion about the effectiveness of the drug were provided by the prescriber, using a standard questionnaire sent 6 months after the initial prescription for tamsulosin. The incidence of each of almost 2000 events listed in the Drug Safety Research Unit computerized dictionary was calculated and scrutinized by medical assessors for possible adverse reactions, and any difference determined between the incidence of each event in the first month and subsequent months of exposure. All deaths were followed up to detect possibly drug-related causes. RESULTS: Event data were obtained on 12484 patients, from the 52.9% of questionnaires returned and that contained valid event data. Tamsulosin was reported to have been effective in 7428 (78.3%) of the 9487 patients in whom the general practitioners expressed an opinion about effectiveness. Suspected adverse drug reactions were reported in only 171 (1.4%) of the cohort. Dizziness, headache, malaise and hypotension were common to the reported adverse reactions, reasons for stopping the drug and events of greatest incidence density. None of the 282 deaths that occurred in this elderly cohort were attributed to the drug. CONCLUSION: This study suggests that tamsulosin has a highly acceptable benefit-to-risk ratio. No untoward features not already mentioned in the prescribing guidance were identified.

Adolescent↗
PubMed2000

ESHRE preimplantation genetic diagnosis (PGD) consortium: data collection II (May 2000).

In 1997, the ESHRE PGD Consortium was formed as part of the ESHRE Special Interest Group on Reproductive Genetics, in order to undertake a long-term study of the efficacy and clinical outcome of preimplantation genetic diagnosis (PGD). In December 1999, the first PGD Consortium report was published discussing referrals of 323 couples, 392 PGD cycles and 82 pregnancies and 79 children born. In the second round of data collection, contributing centres were asked to send in data from their PGD activities before January 1997, as well as from 1st October 1998 until 1st May 2000, in order to have as complete as possible an overview of PGD practices in these centres. A further 563 referrals were sent in as well as 926 PGD cycles, and data on 89 pregnancies (including seven pregnancies ongoing from the previous group) and 83 children were collected. This has led to a considerable amount of cumulative data being acquired: over a period of 7 years (the oldest PGD cycle reported dates from 1994), referral data on 886 couples, cycle data on 1318 PGD cycles and data on 163 pregnancies and 162 babies were collected. In all, these data are encouraging: they show first, that the practice of PGD is becoming more and more established, and an increasing number of different applications is emerging; and second, that collecting these data is worthwhile, as they will be a valuable source of information for all those involved, e.g. in counselling patients and interacting with governmental bodies.

Aneuploidy↗
PubMed1999

Losartan: a study of pharmacovigilance data on 14,522 patients.

The objective of this study was to undertake a post- marketing safety surveillance study of losartan, the first specific angiotensin-II receptor antagonist to be marketed in England. It is a non-interventional observational cohort study using the technique of prescription-event monitoring. Subjects who took part in the study were from 14 522 patients treated by general practitioners in England. We recorded adverse drug reactions, adverse events, reasons for stopping the drug, pregnancies and deaths. The results were that general practitioners considered the drug to have been effective in 85.9% of the patients evaluated for effectiveness. Dizziness, malaise, lassitude, nausea, cough and headache were among the most frequently reported adverse drug reactions, reasons for stopping the drug and events of highest incidence density. None of the deaths that occurred were attributed to losartan and no serious unexpected adverse reactions or interactions were identified. In conclusion losartan has an acceptable safety profile and the study confirms the safety information given in the current Summary of Product characteristics for losartan.

Age Distribution↗
PubMed1999

Detection of aneuploidy in single cells using comparative genomic hybridization.

The ability of comparative genomic hybridization (CGH) to detect aneuploidy following universal amplification of DNA from a single cell, or a small number of cells, was investigated with a view to preimplantation diagnosis following in vitro fertilization, and prenatal diagnosis using fetal erythroblasts obtained from maternal blood. The DNA obtained from lysed single cells was amplified using degenerate oligonucleotide-primed PCR (DOP-PCR). This product was labelled using nick translation and hybridized together with normal reference genomic DNA. The CGH fluorescent ratio profiles obtained could be used to determine aneuploidy with cut-off thresholds of 0.75 and 1.25. Deviation in the profiles in the heterochromatic regions was reduced by using, as a reference sample, normal genomic DNA that had also undergone DOP-PCR. Single cells known to be trisomic for chromosomes 13, 18 or 21 were analysed using this technique. The resolution of CGH with amplified DNA from a single cell is of the order of 40 Mb, sufficient for the diagnosis of trisomy 21, and possibly segmental aneuploidy of equivalent size. These results, and those of others, demonstrate that diagnosis of chromosomal aneuploidy in single cells is possible using CGH with DOP-PCR amplified DNA.

Aneuploidy↗