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Biomedical subjects

D Barlow

Publications and source records attributed to D Barlow.

At least 19 recordsLinked to original sources
PubMed1998

Superovulation with a high gonadotropin dose for in vitro fertilization: is it effective?

PURPOSE: Our purpose was to investigate the effect on the ovarian response of increasing the gonadotropin dose. METHODS: We analyzed retrospectively the in vitro fertilization data for patients who had two cycles of treatment, with a higher dose in cycle 2. The patients were stratified according to age, ovarian response, and gonadotropin dose in the first cycle. The main outcome measure was the number of follicles, eggs, and embryos and the peak estradiol (E2) level. RESULTS: The study included 244 patients. Patients in both age groups (n = 118, < or = 33 years; n = 126, > 33 years), low (n = 66) and intermediate (n = 145) responders, and patients who received < 225 IU follicle-stimulating hormone (n = 175) in cycle 1 had a better response in cycle 2. However, the high responders (n = 33) and those who received 225 or 300 IU follicle-stimulating hormone (n = 69) in cycle 1 showed a similar response in both cycles, except for a significantly higher E2 level in cycle 2. CONCLUSIONS: Our results indicate that exceeding a daily dose of 300 IU is unrewarding.

Adult↗
PubMed1998

Evidence from human oocytes for a genetic bottleneck in an mtDNA disease.

We have examined oocytes from a patient with Kearn-Sayre syndrome caused by mtDNA rearrangements. In mtDNA diseases, mutant and wild-type mtDNA frequently coexist in affected individuals (the condition of heteroplasmy). The proportion of mutant mtDNA transmitted from mother to offspring is variable because of a genetic bottleneck, and the "dose" of mutant mtDNA received influences the severity of the phenotype. The feasibility of prenatal diagnosis is critically dependent on the nature and timing of this bottleneck. Significant levels of rearranged mtDNA were detectable in the majority of the patient's oocytes, by use of multiplex PCR, with wide variation, in the levels of mutant and wild-type molecules, between individual oocytes. We also used length variation in a homopolymeric C tract, which is often heteroplasmic in normal controls, to identify founder subpopulations of mtDNAs in this patient's oocytes. We present direct evidence that the number of segregating units (n) is three to five orders of magnitude less than the number of mitochondria in the human female oocyte. In some cases, the best estimate of n may correspond to a single mitochondrion, if it is assumed that intergenerational transmission of mtDNA can be treated as a single sampling event. The bottleneck appears to contribute a major component of the variable transmission from mother to oocyte, in this patient and in a control. That this bottleneck had occurred by the time that oocytes were mature advances the prospects for prenatal diagnosis of mtDNA diseases.

DNA Primers↗
PubMed1998

Do gastrointestinal symptoms vary with the menstrual cycle?

This systematic review presents both the physiological and symptom-based studies which have explored gastrointestinal variation across the menstrual cycle. Understanding this variation may be helpful in identifying the origin of pelvic pain, particularly as the symptoms associated with causes, such as endometriosis, also vary across the cycle. One-third of otherwise asymptomatic women may experience gastrointestinal symptoms at the time of menstruation, and almost 50% of women with irritable bowel syndrome report a perimenstrual increase in symptoms.

Abdominal Pain↗
PubMed1997

Gonorrhoea in inner London: results of a cross sectional study.

OBJECTIVES: To estimate population based incidence rates of gonorrhoea in an inner London area and examine relations with age, ethnic group, and socioeconomic deprivation. DESIGN: Cross sectional study. SETTING: 11 departments of genitourinary medicine in south and central London. SUBJECTS: 1978 first episodes of gonorrhoea diagnosed in 1994 and 1995 in residents of 73 electoral wards in the boroughs of Lambeth, Southwark, and Lewisham who attended any of the departments of genitourinary medicine. MAIN OUTCOME MEASURES: Yearly age, sex, and ethnic group specific rates of gonorrhoea per 100,000 population aged 15-59 years; rate ratios for the effects of age and ethnic group on gonorrhoea rates in women and men before and after adjustment for confounding factors. RESULTS: Overall incidence rates of gonorrhoea in residents of Lambeth, Southwark, and Lewisham were 138.3 cases yearly per 100,000 women and 291.9 cases yearly per 100,000 men aged 15-59 years. At all ages gonorrhoea rates were higher in non-white minority ethnic groups. Rate ratios for the effect of age adjusted for ethnic group and underprivilege were 15.2 (95% confidence interval 11.6 to 19.7) for women and 2.0 (1.7 to 2.5) for men aged 15-19 years compared with those over 30. After deprivation score and age were taken into account, women from black minority groups were 10.5 (8.6 to 12.8) times as likely and men 11.0 (9.7 to 12.6) times as likely as white people to experience gonorrhoea. CONCLUSIONS: Gonorrhoea rates in Lambeth, Southwark, and Lewisham in 1994-5 were six to seven times higher than for England and Wales one year earlier. The presentation of national trends thus hides the disproportionate contribution of ongoing endemic transmission in the study area. Teenage women and young adult men, particularly those from black minority ethnic groups, are the most heavily affected, even when socioeconomic underprivilege is taken into account. There is urgent need for resources for culturally appropriate research and effective intervention to prevent gonococcal infections and their long term sequelae in this population.

Adolescent↗
PubMed1997

Psychological effects of continuation versus discontinuation of hormone replacement therapy by estrogen implants: a placebo-controlled study.

There is conflicting evidence regarding the effects of hormone replacement therapy (HRT) with estrogens on psychological and psychiatric symptoms of menopause. Forty women already attending a menopause clinic for continuing HRT by estrogen implants were studied in a randomized, double-blind, placebo-controlled study of estrogen reimplantation versus implantation of a placebo preparation. Assessment included self rating with visual analog scales, standardized psychological and menopause rating scales (Hospital Anxiety and Depression Scale, Self-Concept Questionnaire, Cognitive Failures Questionnaire, Greene Menopause Index), and interview with the Present State Examination. No difference in outcome with regard to either psychological or psychiatric symptoms was found 2 months after entry to the study between the women who received an active implant and those who received a placebo implant, in spite of the former group having a significant rise in estradiol levels. The only effect of HRT on physical symptoms was a nonsignificant reduction in flushes. Psychiatric morbidity of the study population was high with nearly half being "psychiatric cases" according to the Present State Examination at both initial assessment and follow-up. At entry to the study nearly all the women had levels of estradiol in the premenopausal range and four had supraphysiological levels. It appears likely that women were returning requesting a new implant because of symptoms related to nonhormonal factors. Women receiving continuing HRT for menopausal symptoms should be reassessed both for hormonal status and current psychosocial factors when they present with recurrent symptoms, especially those of a psychological or psychiatric nature.

Adult↗
PubMed1997

Infertility treatment and multiple birth rates in Britain, 1938-94.

Trends in multiple birth rates are thought to have been substantially affected by subfertility treatments in the last 25 years, but there are few quantitative assessments of this. This paper examines trends in twin and higher multiple birth rates separately in Scotland, England and Wales and compares their course with corresponding multiple birth rates in the Oxford Record Linkage Study area, where the proportions following subfertility treatment are documented. National data on prescriptions for subfertility treatments reinforce the view that they have had a major effect on the trends, and currently perhaps 60% of triplet and higher order births and 15% of twins follow their use in Britain.

Birth Rate↗
PubMed1997

Uterine cavity assessment prior to in vitro fertilization: comparison of transvaginal scanning, saline contrast hysterosonography and hysteroscopy.

A total of 44 patients undergoing in vitro fertilization (IVF) and requiring uterine cavity assessment agreed to have both saline contrast hysterosonography (SCHS) and hysteroscopy. SCHS was performed following a baseline transvaginal scan by injection of saline into the uterine cavity during continuous scanning. Hysteroscopy was performed with a flexible fiberscope with a 3.6-mm outer diameter; 38 of 44 women (86%) underwent both procedures. Hysteroscopy diagnosed intrauterine abnormalities in 16 women. SCHS was in complete agreement in 13 of 16 cases. As a screening test for any cavity abnormality, SCHS had a 87.5% sensitivity, 100% specificity, 100% positive predictive value and 91.6% negative predictive value. In 14 women, an abnormal uterine cavity was apparent on transvaginal scanning (TVS). However, TVS, unlike SCHS, could not (1) confidently diagnose submucosal fibroids in the presence of a uterus with multiple fibroids; (2) distinguish between a hyperplastic endometrium and a large polyp; or (3) differentiate between an arcuate and a septate uterus. In addition, ovarian pathology was diagnosed on TVS in five women: endometrioma (n = 1), complex cysts (n = 2) and polycystic ovaries (n = 2). SCHS is a simple, accurate, well-tolerated procedure that can be performed within a fertility unit, avoiding invasive and expensive diagnostic hysteroscopy. Significant findings can be treated by operative hysteroscopy prior to commencing an IVF treatment cycle.

Adult↗
PubMed1997

Is routine diagnostic laparoscopy for infertility still justified? A pilot study assessing the use of hysterosalpingo-contrast sonography and magnetic resonance imaging.

We assessed the value of hysterosalpingo-contrast sonography (HyCoSy) and magnetic resonance imaging (MRI) as alternatives to laparoscopy and dye insufflation with or without hysteroscopy in the investigation of infertility. A total of 19 women had all three procedures, in addition, one became pregnant after HyCoSy alone. The findings were: uterine fibroids (n = 5), minimal-mild endometriosis (n = 4) and moderate-severe endometriosis (n = 3) including one case of bilateral endometriomas, endometrial polyp (n = 1), polycystic ovaries (n = 2), bilateral dermoid cysts (n = 1), haemorrhagic corpus luteal cyst (n = 1) and minimal adhesions (n = 3). At laparoscopy, 31/37 tubes were patent and there was 84% concordance with the tubal patency findings at HyCoSy. The uterine fibroids and ovarian cysts were detected using transvaginal scanning; the endometrial polyp and a congenital uterine anomaly were identified using HyCoSy. These findings were detected using MRI, but in addition the technique distinguished the dermoid cysts from the endometriomas, identified the two other cases of moderate-severe endometriosis, fibroids <2 cm (n = 2) and adenomyosis (n = 5), and interpreted the haemorrhagic corpus luteum as an endometrioma. Our data suggest that women with normal HyCoSy and MRI findings have a normal pelvis and may not need routine surgical investigation.

Adult↗
PubMed1997

Assortative sexual mixing in a heterosexual clinic population--a limiting factor in HIV spread?

OBJECTIVE: To assess the degree of sexual mixing in a sexually transmitted disease clinic population stratified by country of birth. DESIGN: Prospective linked HIV serosurvey incorporating demographic and sexual risk data gathered by a doctor-administered questionnaire. SETTING: The Department of Genitourinary Medicine at St Thomas' Hospital, London, UK. SUBJECTS: Fifteen thousand eight hundred and seventy-eight heterosexuals who attended between April 1992 and February 1995. MAIN OUTCOME MEASURE: The degree of assortative (like-with-like) mixing, after stratification of the population by country of birth, of index patients, their parents and their sexual partners. RESULTS: Sexual mixing in this population of sexually transmitted disease clinic attenders is highly assortative when the CoB of parents (family origin) of index patients is taken into account. CONCLUSION: Our findings help to explain the low spread of heterosexual HIV infection in the UK to date, and may help future projections, and health targeting of those at risk. This model can be applied to other mixed population.

Ambulatory Care Facilities↗
PubMed1997

Heterosexual gonorrhoea at St Thomas'--I: Patient characteristics and implications for targeted STD and HIV prevention strategies.

This paper compares the socio-demographic characteristics of patients with gonorrhoea with a control group of other attendees to an inner-London genitourinary medicine (GUM) clinic. Between 16 May and 21 December 1994 inclusive there were 312 culture-confirmed heterosexually-acquired cases of Neisseria gonorrheae treated in our clinic: 192 (61.54%) men and 120 (38.46%) women. There were significant differences between the population of cases and controls. Both male (z = -5.36, P < 0.001) and female (z = -6.6, P < 0.001) cases were younger than controls. Cases were more likely to be black African-Caribbean than were controls and these differences were more marked in men (chi 2 = 47.85, P < 0.001). Cases were also more likely to reside in south London postal districts than were controls (chi 2 = 24.98, P < 0.001). The implications of these findings for targeted health interventions are discussed and we suggest avenues for further work.

Adolescent↗
PubMed1997

Heterosexual gonorrhoea at St Thomas'--II: Sexual behaviour and sources of infection.

This paper examines sexual behaviour in heterosexuals presenting to an inner-London genitourinary medicine (GUM) clinic with gonorrhoea. When comparing patients' documented sexual histories, there were notable differences between cases and a control group, especially in men. Male cases were more likely to have had both multiple sexual partners (chi 2 = 18.5, P < 0.001) and concurrent sexual relationships (chi 2 = 15.2, P < 0.001) in the 30 days preceding presentation. Unlike cases, male controls were more likely to have used a condom at last intercourse with a 'casual' partner (chi 2 = 17.5, P < 0.001). In an examination of the sources of infection in cases, women were far more likely to have been recipients of gonorrhoea than they were to transmit the infection. The source of their infection was most usually a regular sexual partner. In men, 'casual' and 'regular' partners and 'one night stands' were all important sources of infection. Our hypothesis that case patients would have met the sources of their infection in particular venues was not supported by the results of an original questionnaire survey.

Female↗
PubMed1997

Homopolymeric tract heteroplasmy in mtDNA from tissues and single oocytes: support for a genetic bottleneck.

While mtDNA polymorphisms at single base positions are common, the overwhelming majority of the mitochondrial genomes within a single individual are usually identical. When there is a point-mutation difference between a mother and her offspring, there may be a complete switching of mtDNA type within a single generation. It is generally assumed that there is a genetic bottleneck whereby a single or small number of founder mtDNA(s) populate the organism, but it is not known at which stages the restriction/amplification of mtDNA subtype(s) occur, and this uncertainty impedes antenatal diagnosis for mtDNA disorders. Length polymorphisms in homopolymeric tracts have been demonstrated in the large noncoding region of mtDNA. We have developed a new method, T-PCR (trimmed PCR), to quantitate heteroplasmy for two of these tracts (D310 and D16189). D310 variation is sufficient to indicate clonal origins of tissues and single oocytes. Tissues from normal individuals often possessed more than one length variant (heteroplasmy). However, there was no difference in the pattern of the length variants between somatic tissues in any control individual when bulk samples were taken. Oocytes from normal women undergoing in vitro fertilization were frequently heteroplasmic for length variants, and in two cases the modal length of the D310 tract differed in individual oocytes from the same woman. These data suggest that a restriction/amplification event, which we attribute to clonal expansion of founder mtDNA(s), has occurred by the time oocytes are mature, although further segregation may occur at a later stage. In contrast to controls, the length distribution of the D310 tract varied between tissues in a patient with heteroplasmic mtDNA rearrangements, suggesting that these mutants influence segregation. These findings have important implications for the genetic counselling of patients with pathogenic mtDNA mutations.

Animals↗