Short-term measurement of N2O emissions from sheep-grazed pasture receiving increasing rates of fertiliser nitrogen in Otago, New Zealand

The purpose of this short-term study was to investigate the effect of increasing fertiliser nitrogen (N) application rates on nitrous oxide (N2O) emissions over the late winter/early spring period from sheep-grazed pasture in Otago rolling hill country. We measured N2O gas emissions from plots on a mottled Fragic Pallic hill soil receiving 0, 100 and 500 kg N/ha.year for 2 years. Plots were sampled weekly for 10 weeks over the 2006 winter/spring period using a static chamber method. Increased N fertiliser rate and the attendant increase in stocking rate significantly increased total N2O emissions (P < 0.05). Total N2O emissions for the measurement period were estimated to be 0.08, 0.13 and 1.36 kg N2O-N/ha (s.e.m, 0.1, 0.18 and 0.45) for the 0, 100 and 500 N treatments, respectively. Our results suggest that high application rates of fertiliser N (i.e. 500 kg N/ha.year) and attendant increased stocking rates may significantly increase emissions of N2O even in dry winter/spring conditions in Otago rolling hill country. These results will assist in the development of best management guidelines for reducing N2O emissions from fertiliser N in hill country.

Bacterial vaginal flora in relation to changing oestrogen levels

Hormonal changes may be important in the onset and clearance of bacterial vaginosis. We studied vaginal flora and serum oestradiol levels of 55 women at baseline and during hormonal treatment. None developed bacterial vaginosis (BV) from normal vaginal flora, 69% of women had normal flora at baseline increasing to 91% following hormonal treatment. The mean oestradiol level with BV was 39.07 ng/L compared with 176.41 ng/L with normal flora. Non-smokers had a mean oestradiol level of 173.95 ng/L compared with 118.67 ng/L in smokers. Recombinant follicle-stimulating hormone resulted in a mean oestradiol rise of 113.9 ng/L. The mean rise was 330.4 ng/L with improved vaginal flora but only 15.1 ng/L in persistently abnormal or worsening flora. A rise in oestradiol in this group of women was associated with a significant reduction of abnormal flora. Reversion from BV to normal flora was associated with a greater rise in oestradiol than where abnormal flora persisted or worsened. This study supports a possible hormonal influence in the natural history of BV. The lower oestradiol levels in smokers may help explain their increased risk of BV.

Is the sperm centrosome to blame for the complex polyploid chromosome patterns observed in cleavage stage embryos from an OAT patient?

Oligoasthenoteratozoospermia (OAT) is defined by a combined low count < 20 × 106 sperm/ml, poor motility < 50 % forward progression or < 25 % rapid linear progression and abnormal morphology (5–8 % normal using Kruger strict criteria) and has been associated with increased levels of sperm aneuploidy. Here we report on the cytogenetic findings from three ‘spare’ embryos from a couple that were referred for ICSI because of OAT. The embryos were processed for sequential FISH in three hybridization rounds using probes for chromosomes 3, 7, 9, 13, 17, 18, 21, X and Y. Molecular cytogenetic analysis of nine chromosomes revealed that all three embryos were female polyploid. One of them was uniformly tetraploid for all chromosomes tested, while the remaining two embryos showed evidence of abnormal postzygotic segregation of chromosomes, causing the derivative blastomeres to have uneven chromosomal constitution. In one of them in particular, the non-disjoining chromosomes showed preferential segregation to the same pole, rather than randomly moving towards either pole, suggesting an abnormal spindle and causing the derivative blastomeres to have significantly uneven chromosomal constitutions. The possible scenarios leading to polyploidy and chromosomal imbalance through cytokinetic failure and subsequent abnormal centrosomal distribution are outlined.

Expression of mRNAs for DNA methyltransferases and methyl-CpG-binding proteins in the human female germ line, preimplantation embryos, and embryonic stem cells

Recent evidence indicates that mammalian gametogenesis and preimplantation development may be adversely affected by both assisted reproductive and stem cell technologies. Thus, a better understanding of the developmental regulation of the underlying epigenetic processes that include DNA methylation is required. We have, therefore, monitored the expression, by PCR, of the mRNAs of DNA methyltransferases (DNMTs), methyl-CpG-binding domain proteins (MBDs), and CpG binding protein (CGBP) in a developmental series of amplified cDNA samples derived from staged human ovarian follicles, oocytes, preimplantation embryos, human embryonic stem (hES) cells and in similar murine cDNA samples. Transcripts of these genes were detected in human ovarian follicles (DNMT3A, DNMT3b1, DNMT3b4, DNMT1, MDBs1-4, MeCP2, CGBP), germinal vesicle (GV) oocytes (DNMT3A, DNMT3b1, DNMT1, MDBs1-4, MeCP2, CGBP), mature oocytes (DNMT3A, DNMT3b1, DNMT1, CGBP), and preimplantation embryos (DNMT3A, DNMT3b1, DNMT1, DNMT3L, MBD2, MDB4, CGBP). Differential expression of DNMT3B gene transcripts in undifferentiated (DNMT3b1) and in vitro differentiated human ES cells (DNMT3b3) further demonstrated an association of the DNMT3b1 transcript variant with totipotent and pluripotent human cells. Significantly, whilst the murine Dnmt3L gene is both expressed and essential for imprint establishment during murine oogenesis, transcripts of the human DNMT3L gene were only detected after fertilisation. Therefore, the mechanisms and/or the timing of imprint establishment may differ in humans.

Isolation, characterization and expression of the human Factor In the Germline alpha (FIGLA) gene in ovarian follicles and oocytes

The Factor In the Germline alpha (FIGalpha) transcription factor regulates expression of the zona pellucida proteins ZP1, ZP2 and ZP3 and is essential for folliculogenesis in the mouse. Using the published mouse Figla sequence, BLAST searches identified a human chromosome 2 BAC clone with high sequence identity. Using PCR primers derived from this clone, amplicons derived from ovarian follicles and mature oocytes revealed 100% identity with the appropriate human BAC clone, the expected homology with the mouse Figla gene sequence, and homology on translation with the FIGalpha protein identified in the Japanese rice fish, medaka (Oryzias latipes). PCR expression profiling of this transcript revealed FIGLA mRNA expression in cDNA derived from ovarian follicles (5/5 samples from the primordial through to the secondary stage) mature oocytes (6/9 samples), and less frequently in preimplantation embryos (2/7 samples). Subsequent BLAST searches revealed the predicted full length coding sequence of the human FIGalpha protein which demonstrates 68 and 25% similarity overall to mouse and medaka proteins respectively, with 96 and 57% identity respectively within the basic helix-loop-helix region. This confirms our identification of the human homologue for this gene which maps to chromosome 2p12. Further work is required to understand its role in normal human oocyte development and the potential involvement in human infertility.

Demonstration of a mechanism of aneuploidy in human oocytes using Multifluor fluorescence in situ hybridization

OBJECTIVE

To evaluate the potential of Multifluor fluorescence in situ hybridization (M-FISH) for karyotyping the human oocyte and first polar body.

DESIGN

Prospective case study.

SETTING

Research laboratories, university hospital.

PATIENT(S)

A 33-year-old woman with polycystic ovary syndrome who was undergoing ovarian stimulation and ICSI.

MAIN OUTCOME MEASURE(S)

Karyotyping of all chromosomes within an oocyte and first polar body, using GV stage oocytes matured to metaphase II in vitro.

RESULT(S)

Oocyte hyperploidy was diagnosed by M-FISH to be 23, X +15 cht +19 cht +22 cht. The correspond- ing polar body was hypoploid, with a karyotype of 23, X -15 cht -19 cht -22 cht. This was due to unbalanced predivision at meiosis I. Reprobing confirmed karyotype assignments for chromosomes X, 13, 18, and 21.

CONCLUSION(S)

The mechanism involved in maternally derived aneuploidy can be defined by using M-FISH to simultaneously karyotype both oocyte and first polar body chromosomes at metaphase II. Multifluor FISH may be useful for investigative studies of maternally derived aneuploidy, which is a major cause of preimplantation waste in natural and assisted reproduction.

Ovarian tissue harvested from lymphoma patients to preserve fertility may be safe for autotransplantation

BACKGROUND

Ovarian failure is a common sequel to chemo/radiotherapy in patients successfully treated for cancer. Harvesting, cryopreserving and subsequently re-implanting ovarian cortical grafts can be used to re-establish reproductive potential in women with cancer. The safety issue, however, is of great concern because residual disease in autografted ovarian tissues might cause recrudescence of disease.

METHODS

A total of 30 non-obese diabetic severe combined immunodeficient (NOD/LtSz-SCID) mice were individually xenografted s.c. with frozen-thawed ovarian tissue from 18 patients with lymphoma [13 Hodgkin's lymphoma (HL) and 5 non-Hodgkin's lymphoma (NHL)]. The animals were autopsied at 16 weeks, or earlier if cachectic. The xenograft, liver, spleen, sternum, para-aortic lymph nodes and thymus were prepared for histology, immunohistochemistry and human DNA microsatellite analysis.

RESULTS

None of the animals grafted with ovarian tissue from lymphoma patients developed disease. However, all 3 animals grafted with lymph node tissue from an NHL patient developed B-cell lymphomas that were confirmed as human in origin by DNA microsatellite analysis.

CONCLUSION

Ovarian tissue harvested before high-dose chemotherapy for HL or NHL may not carry a risk of disease transmission by autotransplantation, although the possibility is difficult to exclude completely.

Amplification of DNA sequences in polar bodies from human oocytes for diagnosis of mitochondrial disease

When a preovulatory oocyte reinitiates meiosis, it sheds a cytoplasmic fragment containing mitochondria and a redundant set of chromosomes. We have detected DNA sequences from both the mitochondrial and nuclear genomes in polar bodies from unfertilised human oocytes, demonstrating the feasibility of diagnosing mitochondrial diseases before conception.

Trends in the incidence of ectopic pregnancy in England and Wales from 1966 to 1996

OBJECTIVE

To examine the incidence of ectopic pregnancy over the period 1966 to 1996.

SETTING

England and Wales.

DESIGN

Use of official statistics on hospital discharges, maternities, legal abortions and estimated populations of women aged 15-44 years.

MAIN OUTCOME MEASURES

Incidence rates of ectopic pregnancies.

RESULTS

Between 1966 to 1970 and 1994 to 1996 the recorded incidence increased 4.5-fold from 3.45 to 15.5 per 1000 maternities, 3.8-fold from 3.25 to 12.4 per 1000 pregnancies and 3.1-fold from 30.2 to 94.8 per 100,000 women aged 15-44. The rate of increase was not uniform. Incidence approximately doubled between 1966 and 1985, when the official data collection system changed. By 1989, when data from the new system became available, there had been a further almost doubling of recorded incidence. Subsequently, the upward trend appears to have continued until 1991 to 1992 and has remained stable in the last four years of the study. The trends were similar in each of three 10-year age groups.

CONCLUSIONS

The recorded incidence of ectopic pregnancy has increased markedly over the last three decades. This may be partly due to artefacts of data recording and more sensitive diagnostic tests, but it is likely that the actual incidence has increased, probably due to a sexually transmitted agent.

Ovarian tissue cryopreservation: a practical option?

Strategies to preserve fertility in young women undergoing potentially curative chemotherapy for malignant disease have been extremely limited. This limitation stems from the complex physiology of the human oocyte and the difficulties encountered in attempting to cryopreserve both developing and mature oocytes in sufficient quantities. Although in vitro fertilization and embryo cryopreservation can be used in those young women with a partner, this technique is unsuitable for the vast majority of patients and offers only a small chance of a pregnancy. Advances in cryobiology coupled with encouraging results in laboratory animals have prompted research into the storage of ovarian cortical tissue, which in young women is rich in primordial follicles. This tissue can be grafted back into the host, theoretically restoring the possibility of normal fertility. Primordial follicles contain oocytes at their least differentiated stage and appear to be relatively resistant to the combined insults of cryopreservation and the subsequent grafting procedure. Interest in this technique has been fuelled by its successful application in large domestic animals, such that ovarian tissue banking is being rapidly adopted into clinical practice before there is any hard evidence of its efficacy in humans.

The influence of donated gametes on the incidence of hypertensive disorders of pregnancy

Pregnancies achieved from oocyte, sperm or embryo donation are unique, since they have resulted from donor gametes that are immunologically foreign to the mother. Thus, studying the obstetric outcome of such pregnancies may shed some light on the pathophysiology of preeclampsia, particularly in women conceiving with donated embryos, since the entire fetal genome is allogenic in these pregnancies. In this retrospective cohort study, a total of 144 women were studied. Of these, 72 were infertility patients who had conceived as a result of sperm, ovum or embryo donation and the other 72 women were age- and parity-matched control patients who became pregnant with their own gametes, either spontaneously, or following intrauterine insemination with their partner's spermatozoa. Study patients were divided into three groups depending on the origin of the donated gametes. Group 1 consisted of pregnancies achieved by intrauterine insemination with washed donor spermatozoa (n = 33). Group 2 included women who conceived using donated oocytes (n = 27) and group 3 consisted of women who conceived as a result of embryo donation (n = 12). The incidence of pregnancy-induced hypertension in the donated gametes study group was 12.5% (9/72) compared with 2.8% (2/72) in the control group. In addition, pre-eclampsia was diagnosed in 18.1% (13/72) of the donated gametes study group compared to 1.4% (1/72) in the age- and parity-matched controls. The increased incidence of gestational hypertension in pregnancies resulting from donated gametes gives evidence for a maternal genetic component, with an equally strong fetal influence, in the complicated aetiology of gestational hypertension, and pre-eclampsia in particular.

Glucose-free medium in human in vitro fertilization and embryo transfer: a large-scale, prospective, randomized clinical trial

OBJECTIVE

To determine whether excluding glucose from the culture medium used in a clinical IVF program improves human embryo quality and pregnancy rates.

DESIGN

Randomized controlled trial.

SETTING

Clinical assisted conception laboratory in a large teaching hospital.

PATIENT(S)

Seven hundred forty-one patients undergoing IVF-ET.

INTERVENTION(S)

Embryos were cultured from the pronucleate stage to ET in medium with glucose for patients in the control group and without glucose for patients in the trial group.

MAIN OUTCOME MEASURE(S)

Comparison of embryo quality and pregnancy rates between the two groups.

RESULT(S)

Embryo quality was enhanced with the use of glucose-free medium but pregnancy rates were similar.

CONCLUSION(S)

Although pregnancy rates remained similar in the two groups, a reduction in the glucose concentration of the medium used for embryo culture from the pronucleate stage to ET on day 2 or 3 is prudent.

Influence of bacterial vaginosis on conception and miscarriage in the first trimester: cohort study

OBJECTIVES

To assess whether bacterial vaginosis affects the rates of conception and miscarriage in the first trimester.

DESIGN

Cohort study.

SETTING

Assisted conception unit of a teaching hospital in Leeds.

PARTICIPANTS

867 consecutive women undergoing in vitro fertilisation.

INTERVENTIONS

Screening for bacterial vaginosis with a Gram stained vaginal smear before egg collection.

MAIN OUTCOME MEASURES

The presence of bacterial vaginosis or normal vaginal flora, and the rate of conception and miscarriage in the first trimester.

RESULTS

190 of 771 (24.6%) women had bacterial vaginosis. No difference in conception rate was found between those women with bacterial vaginosis and those with normal vaginal flora: 61 women (32.1%) and 146 of 493 women (29.6%) respectively (relative risk 1. 08, 95% confidence interval 0.85 to 1.39; odds ratio 1.12, 0.77 to 1. 64). However, 22 women (31.6%) with bacterial vaginosis who conceived had a significantly increased risk of miscarriage in the first trimester compared with 27 women (18.5%) with normal vaginal flora (crude relative risk 1.95, 1.11 to 3.42; crude odds ratio 2.49, 1.21 to 5.12). This increased risk remained significant after adjustment for factors known to increase the rate of miscarriage: increasing maternal age, smoking, history of three or more miscarriages, no previous live birth, and polycystic ovaries (adjusted relative risk 2.03, 1.09 to 3.78; adjusted odds ratio 2.67, 1.26 to 5.63).

CONCLUSIONS

Bacterial vaginosis does not affect conception but is associated with an increased risk of miscarriage in the first trimester in women undergoing in vitro fertilisation, independent of other risk factors.

A laparoscopic technique for obtaining ovarian cortical biopsy specimens for fertility conservation in patients with cancer

OBJECTIVE

To evaluate the efficacy of a newly designed round biopter as a practical and safe method for collecting ovarian tissue for cryopreservation in young women with cancer before chemotherapy.

DESIGN

Prospective study of young women volunteering for research (Leeds, United Kingdom) and patients with cancer (Jerusalem, Israel and Leeds, United Kingdom) undergoing laparoscopic ovarian cortical tissue biopsy and cryopreservation before administration of high-dose radiochemotherapy.

SETTING

Two university-based tertiary referral centers of oncology and gynecology (Hadassah Medical Center, Israel; Leeds General Infirmary, United Kingdom).

PATIENT(S)

Twenty female volunteers undergoing routine laparoscopic gynecologic procedures (age, 25-34 years) and 20 young women (age, 11-30 years) with advanced cancer requiring potentially sterilizing radiochemotherapy.

INTERVENTION(S)

Cortical ovarian tissue biopsies performed under laparoscopy with use of the round biopter.

RESULT(S)

The laparoscopic sampling procedure was uncomplicated in all cases. In treated patients, five to six samples were obtained (5 mm in diameter; 2-3 mm in depth) using the round biopter, and radiochemotherapy was administered without delay. In volunteers, no adhesions were noted at repeat laparoscopy (9 patients). All biopsy specimens were cryopreserved, and histologic examination confirmed the presence of many primordial follicles.

CONCLUSION(S)

Laparoscopic ovarian biopsy performed with the round biopter is a safe and efficient method for collecting ovarian tissue for cryopreservation in patients with cancer.

Induction of ovulation with the use of a starting dose of 50 units of recombinant human follicle-stimulating hormone (Puregon)

OBJECTIVE

To determine whether a starting dose of 50 units of recombinant FSH (follitropin beta, Puregon; Organon Laboratories Limited, Cambridge, United Kingdom) produces a follicular response in patients with clomiphene citrate-resistant polycystic ovary syndrome (PCOS).

DESIGN

Prospective observational study.

SETTING

Routine clinical practice in a teaching hospital fertility unit.

PATIENT(S)

Patients with clomiphene citrate-resistant PCOS who wanted to become pregnant.

INTERVENTION(S)

Low-dose step-up protocol of SC recombinant FSH administration, monitored prospectively by transvaginal ultrasonography and retrospectively by serum endocrine assays taken at each monitoring visit.

MAIN OUTCOME MEASURE(S)

Rate and size of follicular growth, recombinant FSH requirement, E2 response, ovulation, cycle cancellation, and pregnancy.

RESULT(S)

All patients exhibited a follicular response: Six patients ovulated, of whom two conceived and four had their cycles cancelled because of overstimulation. One patient did not ovulate despite the development of a follicle.

CONCLUSION(S)

Recombinant FSH can be used successfully to stimulate follicular growth at a starting dose of 50 IU.

Survey of the diagnosis and management of antisperm antibodies

A questionnaire was sent to all Human Fertilization and Embryology Authority-registered reproductive medicine centres throughout the UK to survey their policy for the diagnosis and management of antisperm antibodies. Forty-eight responses were received from the 74 units that use husbands' spermatozoa for treatments (65%). Most centres use at least one test to detect antibodies, although a minority perform no tests on the basis that their clinical practice would be unaltered if antibodies were present. Positive tests are classed as clinically significant at levels varying from > or = 10% to > or = 50% for direct sperm binding tests (mixed antiglobulin reaction, immunobead test), and ranging from any positive reaction to > or = 1:32 for the microtitre tests (gelatin and tray agglutination tests, microimmobilization test). Strategies for managing affected patients include no intervention, artificial insemination and intrauterine insemination (IUI) using spermatozoa prepared by various techniques, in-vitro fertilization (IVF) with or without increased insemination concentration, and intracytoplasmic sperm injection. Criteria for the latter are diverse, some centres managing all antibody-positive patients this way, while others resort to it only in severe cases or after other treatments have failed. Half of the respondents occasionally or regularly employ steroids, either alone or in conjunction with IUI or IVF. Overall, it appears that much confusion exists as to how best to manage couples presenting with antibody-related infertility.

Pretreatment with follicle stimulating hormone promotes the numbers of human oocytes reaching metaphase II by in-vitro maturation

The objective of this study was to investigate the effect of follicle stimulating hormone (FSH) priming on the in-vitro maturation (IVM) of human oocytes from healthy ovaries using a chemically defined culture system. Seventeen patients donating oocytes for research received a truncated course of 600 IU FSH over 5 days and a further control group of nine patients received no FSH treatment. Mid-follicular phase cumulus-enclosed oocytes (n = 160) were aspirated from follicles < or =4 mm diameter under transvaginal ultrasound guidance and were cultured for 48 h in microdrops of medium containing 10 mIU/ml FSH and 100 mIU/ ml human chorionic gonadotrophin (HCG). The results demonstrated that human oocytes will efficiently undergo IVM under serum-free conditions. After mild FSH stimulation, a greater number of cumulus-enclosed oocytes was collected, and following culture, a lower rate of degeneration was observed. Significantly more oocytes completed nuclear maturation to metaphase II following FSH stimulation (71.1 versus 43.5%). In conclusion, a truncated course of FSH stimulation in vivo improved the oocyte maturation rate in vitro, giving a mean of 4.8+/-0.7 metaphase II oocytes per patient compared with only 2.1+/-0.7 from control patients, thus yielding more mature oocytes for future IVF treatment.

Metabolism of pyruvate by the early human embryo

Pyruvate is added to all media used for human in vitro fertilization and embryo culture, but its function(s) in the early embryo is unknown. We tested the possibility that pyruvate can act as an oxidizable energy source by measuring the consumption of pyruvate and oxygen by Day 2 and Day 3 human embryos, using microfluorometric techniques. Oxygen consumption (19.6 pmol/embryo per hour) could account for the oxidation of only 56% of the pyruvate consumed (13.9 pmol/embryo per hour). Oxygen was also consumed in the absence of exogenous substrates. Lactate appeared in the incubation medium with pyruvate (0.47 mM) as sole exogenous substrate at a rate of 12.1 pmol/embryo per hour, at a similar rate (10.85 pmol/embryo per hour) in the presence of 1 mM glucose and 0.47 mM pyruvate, and at 2.25 pmol/embryo per hour in the absence of exogenous substrates, suggesting that a high proportion of the pyruvate taken up by early human embryos is converted to lactate. Pyruvate uptake in the presence of UK5099, a pyruvate transport inhibitor, was reduced to 10% of control values, consistent with the presence of the monocarboxylate carrier in the human embryo plasma membrane.

Human tubal fluid: production, nutrient composition and response to adrenergic agents

Vascularly perfused Fallopian tubes have been used to study the formation and composition of human tubal fluid and the response to adrenergic agents. An artery serving the tube was cannulated and perfused with Medium 199 supplemented with bovine serum albumin (BSA) and antibiotics. A second cannula was attached to the fimbriated end for native tubal fluid collection. The preparation was viable for up to 2 h. Tubal fluid was only obtained in tubes removed in the proliferative and early secretory phases of the ovarian cycle. Isoproterenol (1 mM) added to the perfusate stimulated fluid production, whereas dibutyryl cyclic AMP (1 mM) reduced fluid formation by 66%. Glucose, pyruvate and lactate concentrations in tubal fluid, measured by microfluorescence assays, were 1.11, 0.14 and 5.4 mM respectively. The concentrations of 17 amino acids in tubal fluid were measured by high performance liquid chromatography following fluorescence derivatization. Arginine (0.19 mM) > alanine (0.11 mM) > glutamate (0.09 mM) were present in highest concentration in all phases of the cycle. All 17 amino acid concentrations in tubal fluid were below those in the vascular perfusate. These data provides the basis for a culture medium whose composition mimics the physiological environment to which early human embryos are exposed.

Autoantibodies and antisperm antibodies in sera and follicular fluids of infertile patients; relation to reproductive outcome after in-vitro fertilization

Immune reactions have effects at various concentrations in the reproductive process and autoantibodies may have an impact on fertility and the outcome of assisted conception. We measured the prevalence of and relation between antibodies to smooth muscle, nuclear, phospholipid and sperm antigens, and concentrations of immunoglobulins G, M and A and complement components C3 and C4, in the sera and follicular fluids of women with unexplained infertility (n = 30), endometriosis (n = 20), tubal infertility (n = 50) and the sera of 20 normal non-pregnant women. We assessed fertilization and successful pregnancy rates in relation to antibody status of infertile women after in vitro fertilization. All antibodies had a higher prevalence in infertile women compared with controls and this was significant for smooth muscle antibody in endometriosis (P < 0.05); anticardiolipin antibody in tubal infertility (P < 0.05); and antisperm antibody in all types of infertility (P < 0.001). There was no relation between presence of specific antibodies in serum or between serum and follicular fluids. Total biochemical pregnancy rate was higher with endometriosis (P = 0.05) but clinical pregnancy and live birth rates did not differ between groups or in relation to antibody status. Significant differences in immunoglobulin and complement components occurred in women with and without successful biochemical pregnancy.

Simultaneous DNA 'fingerprinting', diagnosis of sex and single-gene defect status from single cells

Sex and cystic fibrosis status have been previously diagnosed separately at the single cell level. We have developed a sensitive, reliable, accurate and rapid (within 5-6 h) system for the simultaneous diagnosis of sex, cystic fibrosis and a DNA 'fingerprint' within a single reaction from a variety of single cells. As contamination cannot be totally excluded, particularly at the single cell level, DNA 'fingerprinting' can be used to assess the risk of contamination. High sensitivity with single cells is combined with very high specificity (estimated matching probability of 10(-7)-10(-8)), allowing the source of the amplified cell to be identified with a very high degree of probability. Fluorescent primers were multiplexed for six tetranucleotide microsatellite sequences to determine the DNA fingerprint; the amelogenin gene was used to diagnose sex, and primers for the CFTR region were used to determine cystic fibrosis (CF) status. Analysis of the fluorescent product was undertaken using an automated DNA sequencer with Genescan software. This technique has many applications such as prenatal and preimplantation diagnosis, forensic identification of small or degraded samples, and detection of contamination sources. DNA fingerprints of single haploid spermatozoa and other cells can be assessed, so ensuring the detection of both diploid and haploid contamination during preimplantation diagnosis.

Human tubal fluid: formation and composition during vascular perfusion of the fallopian tube

A vascularly perfused preparation of the Fallopian tube has been developed as a model to study the formation and composition of human tubal fluid. An artery serving the tube was cannulated and perfused at a rate of 0.7 ml/min for 1 h with Medium 199 supplemented with bovine serum albumin, heparin and antibiotics. A cannula was also inserted into the lumen. Light and scanning electron micrographs of control and perfused tubes showed that the epithelial lining was intact after perfusion. Tubal fluid was collected in 13 out of 19 experiments. Fluid could always be collected from patients who were in the follicular phase of their ovarian cycle. The mean rate of appearance was 48 microliters/h. The glucose, lactate and pyruvate concentrations in the tubal fluid, as assessed by fluorescence microanalysis, were 0.53, 8.58 and 0.17 mM respectively. There were no correlations between metabolite concentration and the length of perfusion, cannulation time, patient's age or condition. This technique provides a controlled method with which to access and examine human tubal fluid and will allow the physiology of both healthy and diseased tubes to be studied.

Follicular volume and number during in-vitro fertilization: association with oocyte developmental capacity and pregnancy rate

This study examined the effect of the number of follicles aspirated during egg retrieval on pregnancy likelihood during an ovulation induction, in-vitro fertilization (IVF) programme. In addition, the volume of each individual follicle was related to the probability of obtaining an oocyte from that follicle. Its capacity to be fertilized, the incidence of polyspermic fertilization, the quality of early embryos derived from that oocyte and the influence of patient age were the other outcomes studied. Large follicular number and high mean follicular volume related positively to pregnancy outcome. Successful egg retrieval, normal fertilization and good embryo quality were more likely with increasing individual follicular volume. A model was constructed to quantify the predictive value of follicular fluid volume on the developmental potential of individual oocytes and embryos derived from that follicle. Successful outcome of IVF is more likely if ovulation induction results in many follicles, particularly if they have a high mean volume. Individual oocyte and embryo quality can be traced back to the follicular level.

Organ donation from intensive care units in England

OBJECTIVE

To audit all deaths in intensive care units (excepting coronary care only and neonatal intensive care units) in England to assess potential for organ procurement.

DESIGN

An audit in which 14 regional health authorities and London special health authorities each designated a regional liaison officer to identify intensive care units and liaise with Department of Health and the Medical Research Council's biostatistics unit in distribution, return, and checking of audit forms. Audit took place from 1 January to 31 March 1989 and will continue to 31 December 1990.

SETTING

278 Intensive care units in England.

PARTICIPANTS

Colleagues in intensive care units (doctors, nurses, coordinators, and others), who completed serially numbered audit forms for all patients who died in intensive care.

RESULTS

The estimated number of deaths in intensive care units was 3085, and validated audit forms were received for 2853 deaths (92%). Brain stem death was a possible diagnosis in only 407 (14%) patients (about 1700 cases a year) and was confirmed in 282 (10%) patients (an estimated 1200 cases a year). Half the patients (95% confidence interval 45% to 57%) in whom brain stem death was confirmed became actual donors of solid organs. Tests for brain stem death were not performed in 106 (26%) of 407 patients with brain stem death as a possible diagnosis, and general medical contraindication to organ donation was recorded for 48 (17%) of 282 patients who fulfilled brain stem death criteria before cessation of heart beat. The criteria were fulfilled before cessation of heart beat and in the absence of any general medical contraindication to organ donation in 234 patients, 8% of those dying in intensive care (an estimated 1000 cases a year). Consent for organ donation was given in 152 (70%) of 218 cases (64% to 76%) when the possibility of organ donation was suggested to relatives. In only 14 out of 232 families (6%; 3% to 9%) was there no discussion of organ donation with relatives. Corneal suitability was recorded as "not known" in a high proportion (1271; 45%) of all deaths and intensive care units reported only 123 corneal donors (4% of all audited deaths).

CONCLUSION

When brain stem death is a possible diagnosis tests should always be carried out for confirmation. Early referral to the transplant team or coordinator should occur in all cases of brain stem death to check contraindications to organ donation. There should be increased use of asystolic kidney donation, and patients should be routinely assessed for suitability for corneal donation. Finally, more publicity and education are necessary to promote consent.

Non-invasive measurement of glucose and pyruvate uptake by individual human oocytes and preimplantation embryos

Pyruvate and glucose uptake by 73 individual human oocytes and preimplantation embryos was measured non-invasively, using an ultramicrofluorescence assay to analyse changes in substrate levels in microdroplets of culture medium. The uptake of both substrates was measured over successive daily incubations between days 1 (unfertilized oocytes) or 2 ('spare' embryos which were not transferred) and day 6 (day 0 = day of insemination). Under these conditions, 58% (25/43) of fertilized embryos with two pronuclei on day 1 developed to the blastocyst stage by day 6. The pyruvate uptake of these embryos increased from approximately 28 to a maximum of 40 pmol/embryo/h between days 2.5 and 4.5. Similarly, glucose uptake increased from approximately 8 to 14 pmol/embryo/h between days 2.5 and 4.5, but then increased further to 24 pmol/embryo/h on day 5 at the blastocyst stage. [corrected] The pyruvate uptake of fertilized embryos which arrested at cleavage stages was significantly lower than for those which developed to the blastocyst stage. Polyspermic and parthenogenetic embryos, and unfertilized oocytes also had lower pyruvate uptakes at later stages. The glucose uptake of unfertilized oocytes and abnormal embryos never reached the level of fertilized embryos at the blastocyst stage on day 5.5. Non-invasive measurement of pyruvate uptake before embryo transfer may provide a valuable functional criterion for the selection of viable embryos capable of developing to the blastocyst stage.

Vaginal pH in pregnancy in women delivered at and before term

A microelectrode was used to measure vaginal pH in a longitudinal study during pregnancy in 30 women, 28 of whom were delivered at term. Excluding pH readings made in the presence of pathogenic organisms, 120 readings were taken. The mean vaginal pH of all subjects was 4.16 (SD 0.41). Analysis of variance showed no significant within-subject variation of pH during pregnancy. Two women had spontaneous preterm deliveries (less than 37 weeks) and their mean vaginal pH during pregnancy was 5.05 and 5.06. Eight women admitted in preterm labour, who then gave birth, had a mean pH of 5.43 (SD 0.94) which was significantly higher than the mean pH of 10 women in labour at term (4.58, SD 0.59). The relation between bacterial growth in vitro and the surrounding pH was also examined. Escherichia coli, a potential pathogen, behaved differently from both Lactobacillus (a commensal organism) and Candida albicans. The clinical observations show a trend towards higher vaginal pH values in association with preterm labour.

Improvement of in vitro fertilisation after treatment with buserelin, an agonist of luteinising hormone releasing hormone

Treatment with buserelin, an agonist of luteinising hormone releasing hormone, and human menopausal gonadotrophin was compared with the conventional treatment of clomiphene citrate and human menopausal gonadotrophin in the outcome of in vitro fertilisation. Seventy seven infertile women had 83 cycles of treatment with buserelin and human menopausal gonadotrophin, and concurrently another 328 infertile women were treated with clomiphene citrate and human menopausal gonadotrophin. Seven (8%) cycles were cancelled owing to inadequate super-ovulation or ovarian hyperstimulation in the women receiving buserelin and 103 (31%) were cancelled because of poor follicular development in those receiving clomiphene citrate. The mean number of oocytes recovered was significantly higher with buserelin (9.5 (SD 4.5) v 5.5 (2.2)) as was the mean number of embryos obtained (4.3 (2.4) v 2.9 (1.7)). Significantly more women who had an embryo transfer became clinically pregnant after treatment with buserelin (53% (30/57) v 30% (48/159), or 36% v 14% of treatment cycles). Altogether 33% (10) of pregnancies in women treated with buserelin were multiple compared with 23% (11) in those treated conventionally. Of the 17 completed pregnancies in women treated with buserelin, 11 resulted in the birth of live babies (eight singletons, two sets of twins, and one set of triplets) and six failed, five before 12 weeks' gestation and one at 22 weeks. The 13 continuing pregnancies (32 weeks) were eight singletons, two sets of twins, and three sets of triplets. Of the 48 completed pregnancies in women treated with clomiphene citrate, 35 resulted in the birth of live babies (26 singletons, five sets of twins and four sets of triplets) and 13 failed, eleven before 12 weeks' gestation and two by 27 weeks. Buserelin increased the chance of pregnancy after in vitro fertilisation compared with conventional treatment, but the risk of multiple pregnancy may be increased.

Urethral dilatation compared with cystoscopy alone in the treatment of women with recurrent frequency and dysuria

The relative merits of cystoscopy alone and cystoscopy plus urethral dilatation were compared in a randomised study of women with recurrent frequency and dysuria. One hundred women were studied before and at least 6 months after operation. A detailed questionnaire was completed, the severity of the symptoms was scored and patients underwent urodynamic investigation. Forty-eight patients underwent cystoscopy alone and 52 underwent urethral dilatation. The two groups were well matched with regard to age, parity, menopausal status, previous gynaecological surgery and severity of symptoms. A significant improvement in symptoms was observed in both groups after treatment: 30% had no residual symptoms, 50% were improved and 20% were no better. However, no difference in final outcome was observed between those who had undergone cystoscopy alone and those who had undergone urethral dilatation. Furthermore, 7 patients who underwent urethral dilatation experienced transient stress incontinence of urine, a complication not observed in women who underwent cystoscopy alone. No benefit was observed from the addition of urethral dilatation to cystoscopy alone in women with recurrent frequency and dysuria.