Culture media affect sex after IVF treatment-a detailed analysis of explanatory variables

PURPOSE

The purpose of this study was to provide a detailed analysis of clinical and laboratory factors associated with skewed secondary sex ratio (SSR) after ART.

METHOD

Retrospective cohort study of embryos resulting in live births, from frozen and fresh single blastocyst transfers. Embryos were cultured in either G-TL (n = 686) or Sage media (n = 685). Data was analyzed using a multivariate logistic regression model and a mixed model analysis.

RESULTS

Significantly more male singletons were born after culture in Sage media compared to G-TL media (odds ratio (OR) 1.34, 95% CI (1.05, 1.70), P = 0.02). Inner cell mass grade B vs A (OR 1.36 95% CI (1.05, 1.76), P = 0.02) and one previous embryo transfer (OR 1.49, 95% CI (1.03, 2.16), P = 0.03) were associated with a significantly higher probability of male child at birth. Factors associated with a reduced probability of male child were expansion grade 3 vs 5 (OR 0.66, 95% CI (10.45, 0.96), P = 0.03) and trophectoderm grade B vs A (OR 0.57, 95% CI (0.44, 0.74), P = 0.00). Male embryos developed significantly faster in Sage media compared to G-TL media for the stages of blastocyst (- 1.12 h, 95% CI (- 2.12, - 0.12)), expanded blastocyst (- 1.35 h, 95% CI (- 2.34, - 0.35)), and hatched blastocyst (- 1.75 h, 95% CI (- 2.99, - 0.52)).

CONCLUSION

More male children were born after culture in Sage media compared to G-TL media. Male embryo development was affected by culture media. Our observations suggest that culture media impact male embryo quality selectively, thus potentially favoring the selection of male embryos.

P-193 Using blastocyst re-expansion rate in the decision-making when to warm a new blastocyst for optimal single vitrified-warmed blastocyst transfer

Study question

Can post-warmed blastocyst re-expansion rate be used to identify embryos with low likelihood of live birth (LB) in single vitrified blastocyst transfer (SVBT)?

Summary answer

A statistical model using blastocyst re-expansion rate and Gardner score can be used to identify blastocysts that do not result in live birth.

What is known already

The ability to identify the most viable embryo with greatest chance of implantation and LB is crucial. As embryo development is a dynamic process, research has recently focused on finding the most predictive morphokinetic parameters to incorporate in the assessment of which embryos to select for transfer. Time-lapse systems allow continuous monitoring of the embryo while cultured uninterruptedly. Several studies have found that the degree of blastocoele expansion and re-expansion are significant parameters for prediction of LB. Furthermore, re-expansion rate has been demonstrated to correlate with pregnancy outcomes in SVBT.

Study design, size, duration

This study is a retrospective cohort study including a total of 931 SVBT´s at the Fertility Clinic at Horsens Regional Hospital in a 2-year period from 2019-2020. Prior to vitrification, laser assisted collapsing was performed on all blastocysts with an expansion grade ≤ 4, and grade 5 after individual assessment. Only blastocysts with data on both pre-vitrification Gardner score, LB outcome and at least two hours of post-warmed time-lapse data were included in the analysis.

Participants/materials, setting, methods

Using a time lapse system, both fresh and post-vitrification embryo developmental parameters were evaluated during culturing in an EmbryoScope (Vitrolife, Denmark). Re-expansion rate was calculated as the change in blastocyst area within the first two hours. Logistic regression models were used to estimate the relation between LB and pre- and post-vitrification variables. Based on model predictions, the diagnostic performance was evaluated at thresholds corresponding to a 1%, 2% and 5% false negative rate (FNR).

Main results and the role of chance

Of the 931 SVBT´s, a total of 388 resulted in a LB (41.7%). Using the initial blastocyst size and the two-hour re-expansion rate yielded a model with an area under the ROC curve (AUC) of 0.61 (95% bootstrap CI: 0.57-0.65) Adding pre-vitrification Gardner score to the model increased the AUC to 0.62 (95% bootstrap CI: 0.59-0.66). This model was used to calculate the true negative rate (TNR), being the proportion of transferred blastocysts that would not result in LB at each threshold. At a FNR threshold of 2%, the model predicts that out of 50 discarded blastocysts, 7 would have resulted in a LB and 43 would not have resulted in LB. In summary, the ratio of erroneously discarded embryos vs. correctly discarded embryos would be approximately 1:6 using a 2% FNR.

Limitations, reasons for caution

The statistical model was developed and tested on the same dataset with a risk of overfitting. Any potential clinical application of the model requires testing and validation on an independent dataset. Furthermore, clinical procedures and in particular laser collapse may bias the results.

Wider implications of the findings

Being able to identify blastocysts with a low likelihood of a LB allows for the possibility to thaw a new blastocyst. In a clinical setting, this could lead to a reduced time to pregnancy and LB in women who have multiple vitrified blastocysts.

Trial registration number

1-16-02-583-20

Developmental stage and morphology of the competent blastocyst are associated with sex of the child but not with other obstetric outcomes: a multicenter cohort study

STUDY QUESTION

Are transfer day, developmental stage and morphology of the competent blastocyst in pregnancies leading to live birth associated with preterm birth, birthweight, length at birth and sex of the child?

SUMMARY ANSWER

A high score in blastocyst developmental stage and in trophectoderm (TE) showed a significant association with the sex of the child, while no other associations with obstetric outcomes were observed.

WHAT IS KNOWN ALREADY

The association between blastocyst assessment scores and obstetric outcomes have been reported in small single-center studies and the results are conflicting.

STUDY DESIGN, SIZE, DURATION

Multicenter historical cohort study based on exposure data (transfer day (blastocyst developmental stage reached by Day 5 or Day 6)) blastocyst developmental stage (1-6) and morphology (TE and inner cell mass (ICM): A, B, C)) and outcome data (preterm birth, birthweight, length at birth, and sex of the child) from women undergoing single blastocyst transfer resulting in a singleton pregnancy and live birth.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Data from 16 private and university-based facilities for clinical services and research were used. A total of 7246 women, who in 2014-2018 underwent fresh-embryo transfer with a single blastocyst or frozen-thawed embryo transfer (FET) with a single blastocyst resulting in a singleton pregnancy were identified. Linking to the Danish Medical Birth Registry resulted in a total of 4842 women with a live birth being included. Cycles with pre-implantation genetic testing and donated gametes were excluded. The analyses were adjusted for female age (n = 4842), female BMI (n = 4302), female smoking (n = 4290), parity (n = 4365), infertility diagnosis (n = 4765), type of treatment (n = 4842) and center (n = 4842); some analyses additionally included gestational age (n = 4368) and sex of the child (n = 4833).

MAIN RESULTS AND THE ROLE OF CHANCE

No statistically significant associations between blastocyst assessment scores (transfer day, developmental stage, TE, ICM) and preterm birth (8.3%) or birthweight (mean 3461.7 g) were found. The adjusted association between blastocysts with a TE score of C and a TE score of A and length at birth (mean 51.6 cm) were statistically significant (adjusted mean difference 0.4 cm (95% CI: 0.02; 0.77)). Blastocysts transferred with developmental stage score 5 compared to blastocysts transferred with score 3 had a 34% increased probability of being a boy (odds ratio (OR) 1.34 (95% CI: 1.09; 1.64). Further, TE score B blastocysts compared to TE score A blastocysts had a 31% reduced probability of being a boy (OR 0.69 (95% CI: 0.60; 0.80)).

LIMITATIONS, REASONS FOR CAUTION

It is possible that some residual confounding remains.

WIDER IMPLICATIONS OF THE FINDINGS

Blastocyst selection during ART does not appear to introduce any negative effects on obstetric outcome. Therefore, clinicians and patients can be reassured that the assessment scores of the selected blastocyst will not in themselves pose a risk of preterm birth or affect birthweight and the length at birth.

STUDY FUNDING/COMPETING INTEREST(S)

Unrestricted grant from Gedeon Richter Nordics AB, Sweden. None of the authors have any competing interest to declare.

TRIAL REGISTRATION NUMBER

N/A.

New candidate genes for ST-elevation myocardial infarction

BACKGROUND

Despite extensive research in atherosclerosis, the mechanisms of coronary atherothrombosis in ST-elevation myocardial infarction (STEMI) patients are undetermined.

OBJECTIVES

Our aim was to find candidate genes involved in STEMI by analysing leucocyte gene expression in STEMI patients, without the influence of secondary inflammation from innate immunity, which was assumed to be a consequence rather than the cause of coronary atherothrombosis.

METHODS

Fifty-one patients were included at coronary angiography because of STEMI. Arterial blood was sampled in the acute phase (P1), at 24-48 h (P2) and at 3 months (P3). Leucocyte RNA was isolated and gene expression analysis was performed by Affymetrix Human Transcriptome Array 2.0. By omission of up- or downregulated genes at P2, secondary changes from innate immunity were excluded. Genes differentially expressed in P1 when compared to the convalescent sample in P3 were determined as genes involved in STEMI.

RESULTS

Three genes were upregulated at P1 compared to P3; ABCG1 (P = 5.81 × 10^-5 ), RAB20 (P = 3.69 × 10^-5 ) and TMEM2 (P = 7.75 × 10^-6 ) whilst four were downregulated; ACVR1 (P = 9.01 × 10^-5 ), NFATC2IP (P = 8.86 × 10^-5 ), SUN1 (P = 3.87 × 10^-5 ) and TTC9C (P = 7.18 × 10^-6 ). These genes were also highly expressed in carotid atherosclerotic plaques.

CONCLUSIONS

We found seven genes involved in STEMI. The study is unique regarding the blood sampling in the acute phase and omission of secondary expressed genes from innate immunity. However, the results need to be replicated by future studies.

5234KAND567, the first selective small molecule CX3CR1 antagonist in clinical development, mediates anti-inflammatory cardioprotective effects in rodent models of atherosclerosis and myocardial infarction

Background

Fractalkine is a chemokine that mediates recruitment and extravasation of CX3CR1-expressing subsets of leukocytes and monocytes and has been implicated in the inflammation-driven pathology of cardiovascular disease. More specifically, fractalkine signaling has been proposed to contribute to increased infarct size and enhanced atherosclerotic plaque vulnerability in patients and experimental models. Blocking fractalkine/CX3CR1 signaling is suggested as a promising anti-inflammatory strategy for the treatment of both acute and chronic cardiovascular disease. KAND567 is a small molecule, selective, non-competitive, allosteric antagonist of the fractalkine receptor CX3CR1, that is under preparation for a clinical phase IIa study in AMI patients.

Purpose

To explore the therapeutic effects of the short and long term administration of KAND567 in experimental rodent models of acute myocardial infarction and atherosclerosis, respectively.

Methods

Myocardial infarction was induced in Wistar rats (N=6–8 per group) by ligation of the left anterior descending (LAD) coronary artery for 30 minutes followed by 2 h of reperfusion. The drug or vehicle infusion started either 5 min before or 30 min after start of reperfusion and continued during the remainder of the experiment. Hearts were collected and subjected to triphenyl tetrazolium chlorine (TTC) staining and the infarction area/area at risk of the left ventricle was determined by planimetry and compared against vehicle group.

Atherosclerosis-prone LDL-receptor deficient mice on a high-cholesterol diet, (N=15–25 per group) were treated with KAND567 for 15–23 weeks. Atherosclerotic plaque development in the thoracic arch was determined by ultrasound imaging and histology. Immunohistochemistry was used to follow changes in the cellular composition in the atherosclerotic lesions.

Results

In the acute myocardial infarction study, the infusion of KAND567 before the start of reperfusion significantly reduced infarcted/risk area (by up to 50%) as compared to the vehicle group. However, the infusion had no effect on the infarct size when administration was initiated 30 min after start of reperfusion.

In the atherogenesis study, oral treatment with KAND567 significantly reduced vascular macrophage infiltration by 50% and reduced intima media thickness. Furthermore, reduced plaque volume and a more stable plaque phenotype was noted following treatment with KAND567.

KAND567 experimental results

Conclusion

Specific inhibition of fractalkine-driven inflammation by KAND567 provides cardioprotective, anti-atherosclerotic and plaque stabilizing effects via mechanisms related to immune cell infiltration, in rodent models. Further studies should be initiated to test if KAND567 is a potential candidate drug, targeting the excessive inflammatory injury associated with ischemia/reperfusion in myocardial infarction and providing plaque stabilization by reducing inflammatory risk for recurrent coronary events.

P5713Clinical pharmacology of AZD9977, a novel, selective mineralocorticoid receptor (MR) modulator without K+-sparing properties

Background and purpose

Excessive MR activation is implicated in the pathogenesis of cardiovascular disease. MR antagonists (MRA) are effective and key guideline-directed therapy in patients with heart failure (HF) with reduced ejection fraction. However, clinical adverse events due to hyperkalaemia and a decline in renal function significantly restricts the treatment. AZD9977 is a novel, non-steroidal selective MR modulator that, compared with MRA, displays a differentiated MR-binding pattern and cofactor recruitment profile, and exerts similar organ protective effects to eplerenone with minimal effects on urinary electrolyte handling.

Methods

We performed a randomized, placebo-controlled, single-blind phase 1 study to evaluate the safety, tolerability and pharmacokinetics of oral AZD9977 in healthy men. Three sequential ascending dose cohorts were evaluated, and participants received either AZD9977 (n=6) or placebo (n=3) for 8 days. AZD9977 target doses of 50mg bid, 150mg bid and 300mg bid were explored based on a model predicted dose range comparable to and exceeding the target receptor occupancy levels achieved with approved MRA drugs. The dose of AZD9977 50mg bid is predicted to be equipotent to spironolactone 25mg daily.

Results

27 healthy male subjects aged 23–45 years completed the study. All doses of AZD9977 were well tolerated with no safety concerns identified. A total of 7 adverse events occurred in 4 participants (22.2%) receiving AZD9977 and 8 events occurred in 6 participants (66.7%) receiving placebo, none severe or resulting in withdrawal from the study. Rapid absorption of AZD9977 was observed with median Tmax values ranging from 0.5 to 0.8-hours post-dose and approximate dose proportional kinetics between 50 to 300 mg twice daily, as measured by AUCτ and Cmax. Steady-state levels in plasma were generally reached within 3–4 days. Target engagement was confirmed by a robust dose-dependent rise in mean serum aldosterone levels between Day −1 and Day 7 (Placebo = 43±172pmol/L, AZD9977 50mg bid = 132±83pmol/L, 150mg bid = 447±242pmol/L, 300mg bid = 808±330pmol/L; Figure 1). AZD9977 had no effect on blood pressure or heart rate and did not alter serum electrolyte levels, urinary Na+ excretion, log urinary Na+/K+ ratio (Figure 2), estimated GFR, or urine volumes when compared to placebo-treated subjects.

Figure 1 and Figure 2

Conclusion

These observations in humans are consistent with pre-clinical studies, demonstrating robust MR-receptor engagement without changes in serum K+ and renal electrolyte handling. These characteristics could potentially realise the therapeutic benefit of MR blockade with a low risk of hyperkalaemia. This hypothesis is currently being tested clinically in a head-to-head trial of AZD9977 versus spironolactone in patients with HF and impaired renal function (NCT03682497).

Acknowledgement/Funding

The study was Sponsored and funded by AstraZeneca

P6599Upregulation of protein and gene expression of arginase-1 in patients with ST elevation myocardial infarction

Background

The mechanisms underlying rupture of a coronary atherosclerotic plaque and development of myocardial ischemia-reperfusion injury in ST-elevation myocardial infarction (STEMI) remain unknown. Increased arginase-1 activity leads to reduced nitric oxide production and increased formation of reactive oxygen species due to uncoupling of the endothelial nitric oxide synthase (eNOS). These events lead to endothelial dysfunction, plaque instability and increased susceptibility to ischemia-reperfusion injury in acute myocardial infarction. Experimental studies have shown that arginase-1 expression and activity are increased in atherosclerosis and during myocardial ischemia-reperfusion. Accordingly, inhibition of arginase-1 reduces atherosclerotic lesion development and limits the extent of infarct size during ischemia-reperfusion via an eNOS-dependent mechanism. Furthermore, arginase-1 inhibition improves endothelial function in patients with coronary artery disease but the potential role of arginase-1 in patients with STEMI is poorly understood.

Purpose

The purpose of the current study was to test the hypothesis that arginase-1 is upregulated and correlate to infarct size in STEMI patients.

Methods and results

Two independent cohorts of STEMI patients were included. In cohort 1, plasma and buffy coat leukocytes were collected from 53 STEMI patients at the time of arterial puncture for percutaneous coronary intervention, at 24–48 hours post STEMI and at 3 months post STEMI. Gene expression in leukocytes was determined in 51 patients with Affymetrix Human Transcriptome Array 2.0. In cohort 2, plasma was collected from 82 STEMI patients at admission and at 6 months for determination of plasma arginase-1. These patients underwent cardiac magnetic resonance imaging performed at day 4–7 and at 6 months post STEMI. Plasma arginase-1 levels were quantified with ELISA. Control blood samples were collected from 56 healthy age matched subjects. In cohort 1, ARG1 gene expression was four-fold higher in STEMI patients at admission compared to controls (Figure A). This expression returned to control levels within 3 months. Plasma arginase-1 levels were two times higher in STEMI patients at admission compared to controls, and remained elevated at 24–48 hours and at 3 months post STEMI (Figure B). The increase in plasma arginase-1 in STEMI patients was confirmed in cohort 2 (Figure C). Arginase-1 levels did not correlate with infarct size.

Conclusions

STEMI patients demonstrate increased gene expression and plasma levels of arginase-1 in the acute setting. In contrast to gene expression plasma arginase-1 levels remain significantly elevated over time. The markedly increased expression of arginase-1 already at admission may suggest a mechanistic role of arginase-1 in the development of STEMI. Further studies are needed to elucidate whether increased expression, induction and activity of arginase-1 are contributing factors for the development of STEMI.

Gene expression signatures, pathways and networks in carotid atherosclerosis

BACKGROUND

Embolism from unstable atheromas in the carotid bifurcation is a major cause of stroke. Here, we analysed gene expression in endarterectomies from patients with symptomatic (S) and asymptomatic (AS) carotid stenosis to identify pathways linked to plaque instability.

METHODS

Microarrays were prepared from plaques (n = 127) and peripheral blood samples (n = 96) of S and AS patients. Gene set enrichment, pathway mapping and network analyses of differentially expressed genes were performed.

RESULTS

These studies revealed upregulation of haemoglobin metabolism (P = 2.20E-05) and bone resorption (P = 9.63E-04) in S patients. Analysis of subgroups of patients indicated enrichment of calcification and osteoblast differentiation in S patients on statins, as well as inflammation and apoptosis in plaques removed >1 month compared to <2 weeks after symptom. By prediction profiling, a panel of 30 genes, mostly transcription factors, discriminated between plaques from S versus AS patients with 78% accuracy. By meta-analysis, common gene networks associated with atherosclerosis mapped to hypoxia, chemokines, calcification, actin cytoskeleton and extracellular matrix. A set of dysregulated genes (LMOD1, SYNPO2, PLIN2 and PPBP) previously not described in atherosclerosis were identified from microarrays and validated by quantitative PCR and immunohistochemistry.

CONCLUSIONS

Our findings confirmed a central role for inflammation and proteases in plaque instability, and highlighted haemoglobin metabolism and bone resorption as important pathways. Subgroup analysis suggested prolonged inflammation following the symptoms of plaque instability and calcification as a possible stabilizing mechanism by statins. In addition, transcriptional regulation may play an important role in the determination of plaque phenotype. The results from this study will serve as a basis for further exploration of molecular signatures in carotid atherosclerosis.

HLA-alleles associated with increased risk for extra-pulmonary involvement in sarcoidosis

Genetic factors influence the risk for disease as well as the clinical picture seen in sarcoidosis and especially the genes localized to the human leukocyte antigen (HLA) region on chromosome 6 are of importance. The aim of this study was to further investigate associations between HLA-DRB1 alleles and the risk for extra-pulmonary manifestations (EPMs), i.e. engagement of the skin, superficial lymph nodes, eyes, nervous system, kidneys, hypercalcemia, parotid and salivary glands, heart, liver, spleen and bone marrow in Scandinavian sarcoidosis patients. One thousand patients with together with a group of 2000 healthy individuals, matched for sex and age. HLA-DRB1 alleles were determined for all patients and controls. Excluding erythema nodosum and ankle arthritis, we found 288 of 1000 patients to have EPMs. There were 383 patients with Löfgren's syndrome (LS), and among them EPM were relatively uncommon and diagnosed in only 31 (8.1%) of the patients. In contrast, among the 617 non-LS patients, 257 (41.6%) had EPM (P < 0.0001). In LS patients, the absence of HLA-DRB1*03 substantially increased the risk factor for EPM (erythema nodosum and ankle arthritis excluded) (P < 0.0001). A distinct HLA allele combination, HLA-DRB1*04/*15, was identified as a risk factor for EPM in all patients (25 of 50 with DRB1*04/15 had EPM). In conclusion, EPM are common in non-LS sarcoidosis. Furthermore, HLA-typing of sarcoidosis patients can be used in the clinic to identify patients with an increased risk for EPM.

Correlations between clinical variables and gene-expression profiles in carotid plaque instability

OBJECTIVE

Strokes, a major cause of disability, are often caused by embolism from unstable carotid plaques. The aim of this study was to validate a biobank of human carotid endarterectomies as a platform for further exploration of pathways for plaque instability. For this purpose, we investigated the relationship between clinical parameters of plaque instability and expression of genes previously shown to be associated with either plaque instability or healing processes in the vessel wall.

METHODS

A database of clinical information and gene-expression microarray data from 106 carotid endarterectomies were used.

RESULTS

Expression of matrix metalloproteinase (MMP)-9 and MMP-7 was 100-fold higher in plaques than in normal artery. In general, genes associated with inflammation (such as RANKL and CD68) were overexpressed in symptomatic compared with asymptomatic plaques. Plaques obtained from patients undergoing surgery within 2 weeks after an embolic event showed up-regulation of genes involved in healing reactions in the vessel wall (including elastin and collagen). Statin treatment, as well as echodense lesions, were associated with a more stable phenotype.

CONCLUSION

Here, we demonstrate that gene-expression profiles reflect clinical parameters. Our results suggest that microarray technology and clinical variables can be used for the future identification of central molecular pathways in plaque instability.

Expression of fatty acid-binding protein 4/aP2 is correlated with plaque instability in carotid atherosclerosis

OBJECTIVE

the molecular basis for atherosclerotic plaque vulnerability with high risk of plaque rupture and thromboembolism is complex. We investigated whether clinical estimates of plaque stability correlate with differentially expressed mRNA transcripts within the lesion.

METHODS AND RESULTS

endarterectomy samples from patients undergoing surgery for symptomatic and asymptomatic carotid stenosis were prospectively collected and clinical parameters recorded in the Biobank of Karolinska Carotid Endarterectomies. mRNA expression profiling (n = 40) and quantitative RT-PCR (n = 105) revealed increased levels of fatty acid-binding protein 4 (FABP4/aP2) in lesions from patients with recent symptoms of plaque instability compared to asymptomatic patients (array: FC = 2, P < 0.05; RT-PCR: P < 0.05). At the mRNA level, FABP4/aP2 correlated with the cell markers CD36, CD68 and CD163 of monocyte/macrophage lineage as well as with CD4-positive T cells. FABP4/aP2 mRNA expression was also correlated with enzymes of the leukotriene pathway, 5-lipoxygenase and leukotriene A4 hydrolase. In addition, analysis of transcript profiles identified CD52 and adipophilin as the mRNAs with the highest correlation with FABP4/aP2. Expression of FABP4/aP2 by macrophages and CD52 by T cells in the lesion was confirmed by immunohistochemistry.

CONCLUSIONS

expression of FABP4/aP2 is increased at the mRNA level in unstable carotid plaques. Immunohistochemical analyses showed localization of FABP4/aP2 to macrophage populations. These FABP4/aP2-positive macrophages constitute an important and prevalent phenotype and could provide a new link between scavenging-mediated lipid uptake and cellular metabolic stress in plaque. In addition FABP4/aP2 correlates with other important signs of inflammation and plaque instability, such as T cells and leukotriene enzymes. Taken together, these results indicate that FABP4/aP2 is a key factor connecting vascular and cellular lipid accumulation to inflammation.

Continuous hypoxic culturing maintains activation of Notch and allows long-term propagation of human embryonic stem cells without spontaneous differentiation

OBJECTIVE

The maintenance of pluripotency of human embryonic stem cells (hESCs) requires a high efficiency of self-renewal. During in vitro propagation, however, hESCs have a propensity to differentiate spontaneously. In this study, we assessed the nature of hESC responses to hypoxic conditions.

MATERIALS AND METHODS

Human embryonic stem cells were grown in normoxic and hypoxic conditions, and the cells expressing Oct4 and stage-specific embryonic antigen-1 were identified by indirect immunofluorescence. The transcriptional expression of Nanog, Notch1, and Oct4 was determined by a real-time reverse transcription-polymerase chain reaction, and the inhibition of Notch-mediated signalling was achieved with a gamma-secretase inhibitor.

RESULTS

In contrast to culture at 21% oxygen, where the colonies displayed a marked degree of differentiation, we found that during exposure to 5% oxygen, the hESC colonies displayed a homogenous and flat morphology that was consistent with the presence of Oct4-positive phenotype, indicating no spontaneous differentiation. When cultured at 5% oxygen for either 4 weeks or up to 18 months, high levels of Nanog and Notch1 transcriptional expression were detected, albeit the expression was significantly lower during longer exposure. The suppression of differentiation was rapidly reversed on transfer of the hypoxic cultures to normoxic conditions. Looking into the molecular mechanisms of the maintenance of self-renewal at low oxygen tensions, we found that inhibition of Notch signalling fully abrogated the hypoxic induction of undifferentiated phenotype.

CONCLUSION

Our data, thus, indicate that hypoxic exposure has the capacity to sustain long-term self-renewal of hESCs and that this effect is mediated through activation of Notch.

Malformation rate and sex ratio in 412 children conceived with epididymal or testicular sperm

BACKGROUND

Follow-up studies of children conceived after ICSI using epididymal or testicular sperm are important due to a still more extensive use of immature male germ cells for ICSI. It is, however, difficult to evaluate the potential risks of malformations of children born after ICSI, overcoming the natural fertilization processes, due to methodological limitations.

METHODS

Follow-up study including all children born in Denmark and Norway following ICSI in Denmark, using epididymal or testicular sperm, was done. A questionnaire was sent to the parents between 3 months and 7 years after delivery.

RESULTS

Of 341 couples, 329 returned the questionnaire giving a response rate of 96.5%. The study included 412 children, 225 girls and 187 boys, giving a sex ratio (males/males + females) of 45.4% compared with 53.1% in Danish children conceived after conventional IVF without ICSI (P < 0.005). Among a total of 14 (3.4%; 95% confidence interval (CI): 1.9%-5.7%) major malformations, three boys with hypospadias were the most remarkable finding (1.6%; 95% CI: 0.33-4.7%).

CONCLUSIONS

An increased frequency of hypospadias in the male offsprings was seen compared with the general population. Apart from this, no increased major malformation rate was detected in ICSI children conceived with epididymal or testicular sperm when compared with malformation rates for IVF or spontaneously conceived children reported in the literature. The sex ratio was significantly lower for ICSI children conceived with epididymal or testicular sperm when compared with children conceived with conventional IVF.

Parameters predicting the implantation rate of thawed IVF/ICSI embryos: a retrospective study

Single embryo transfer is becoming increasingly popular in IVF/ICSI. More IVF/ICSI cycles therefore include freezing of high quality embryos, and the cumulative effect of such cycles becomes more important. To improve the results obtained using frozen-thawed embryos, the predictive value of embryo and patient characteristics was analysed retrospectively. Excess embryos were frozen on day 2 according to routine procedures and thawed 24 h before transfer. The women were either treated with oestradiol/progesterone, or the transfer took place after a natural cycle. Of 1777 embryos thawed, 1360 survived (survival rate 76.5%). In the 410 transfer cycles, 819 embryos were transferred, giving 109 positive serum HCG tests and 69 clinical pregnancies. The implantation rate was 10.4%. Five parameters were positively related to implantation: (i) four or more cells at the freezing time (day 2); (ii) resumption of mitosis after thawing; (iii) more than six cells at transfer (day 3); (iv) assisted hatching and (v) child in a previous fresh cycle. The relative predictive value of these parameters may be a guideline for the selection of embryos used for transfer. Assisted hatching may become routine in freeze-thaw cycles if its utility is confirmed in subsequent studies.

Assisted hatching improves implantation rates on cryopreserved-thawed embryos. A randomized prospective study

BACKGROUND

Focus on the hatching process has so far been in the field of fresh embryos. Cryopreserved-thawed embryos have a lower rate of pregnancy than fresh embryos, which might be due to hardening of the zona pellucida.

METHODS

During a 2 year period, a prospective randomized study enrolling 253 cryopreserved-thawed cycles was performed on day 2 embryos. Pseudorandomization to assisted hatching or a control group was done on the basis of even and odd dates for thawing. One hour before embryo transfer, hatching was carried out using acidic Tyrode's solution.

RESULTS

Among 136 embryos exposed to assisted hatching, 11.4% (30) were implanted compared with only 5.8% (13) of 117 embryos not exposed to assisted hatching (P<0.05, chi(2) test). No difference in the rate of clinical pregnancy and positive serum HCG was observed between the two groups. Very few women >38 years old were included in the study, and no significant difference according to age could be found between the groups.

CONCLUSIONS

These results show that assisted hatching using acidic Tyrode's solution increases the implantation rate of cryopreserved-thawed embryos (P<0.05).

Systemic vascular resistance during brief withdrawal of angiotensin converting enzyme inhibition in heart failure

We tested the hypothesis that moderate increases in endogenous angiotensin II (Ang II) concentrations, induced by withdrawal of angiotensin converting enzyme inhibition (ACE-I) in patients with compensated heart failure (HF) on chronic medical therapy, do not increase or impair control of systemic vascular resistance (SVR). SVR was determined in supine and seated positions in 12 HF patients [NYHA class II-III; ejection fraction=0.29 +/- 0.03 (mean +/- SE)] and 9 control subjects. HF patients were investigated during high (n=11; withdrawal of ACE-I treatment for 24 h) and low (n=9; sustained ACE-I therapy) endogenous plasma Ang II concentrations. Withdrawal of ACE-I therapy in HF caused moderately increased Ang II concentrations of 30 +/- 5 pg/ml compared with 12 +/- 2 pg/ml in controls (p<0.05 vs. HF patients). Despite this, SVR was similar in HF (supine: 1503 +/- 159; seated: 1957 +/- 262 dyn s/cm5, p<0.05 vs. supine) and controls (supine: 1438 +/- 104; seated: 1847 +/- 127 dyn s/cm5, p<0.05 vs. supine). During sustained ACE-I therapy in HF, plasma Ang II concentrations were lower (6 +/- 2pg/ml, p<0.05 vs. withdrawal of ACE-I in HF) with no effect on supine SVR. However, the posture-induced increase in SVR in response to the seated position was attenuated. In conclusion, brief moderate increases in circulating plasma Ang II concentrations in compensated HF do not increase SVR compared to control subjects or impair control of SVR in response to a posture change.

Atrial distension, haemodilution, and acute control of renin release during water immersion in humans

We tested the hypothesis that atrial distension (stimulation of cardiopulmonary baroreceptors) is not the single pivotal stimulus for the acute suppression of renin release during water immersion in humans and that immersion-induced haemodilution constitutes an important additional stimulus. In nine healthy male subjects, identical increases in atrial distension were induced by two immersion procedures (of 30 min each); one without (WI) and one with attenuation (WI + cuff) of the concomitant haemodilution (estimated from changes in plasma protein concentration) by inflating thigh cuffs during immersion. During WI, central venous pressure (CVP) and left atrial diameter (LAD) increased (P < 0.05) by 5.5 +/- 0.4 mmHg and 4.6 +/- 0.5 mm, respectively, and plasma protein concentration and plasma renin activity (PRA) progressively decreased (P < 0.05) by 4.8 +/- 0.5 g L(-1) and 1.6 +/- 0.2 ng mL(-1) h(-1) (to 49 +/- 4% of baseline values), respectively. The WI + cuff caused similar atrial distension as WI (CVP and LAD increased by 6.9 +/- 0.5 mmHg and 5.5 +/- 0.5 mm, respectively), attenuated haemodilution (plasma protein concentration decreased by 1.9 +/- 0.4 g L(-1), P < 0.05 vs. WI), and markedly inhibited suppression of PRA, which decreased by 0.4 +/- 0.1 ng mL(-1) h(-1) (to 87 +/- 4% of baseline values, P < 0.05 vs. WI). Differences in renin release could not be accounted for by differences in mean arterial pressure. In conclusion, baroreceptor stimulation induced by atrial distension is not the single pivotal stimulus for the acute suppression of renin release in response to intravascular volume expansion by water immersion in humans. Haemodilution constitutes a significant and conceivably the principal stimulus for the acute immersion-induced suppression of renin-angiotensin system activity.

Cardiovascular and neuroendocrine responses to left lateral position in non-obese young males

Previous results from our laboratory indicate that the heart is distended by the left lateral position (LAT) compared to horizontal supine (SUP). We therefore tested the hypothesis that cardiac output is increased by LAT and that mean arterial pressure is maintained unchanged or even decreased through peripheral vasodilatation induced by cardiopulmonary low-pressure receptor stimulation. Twelve non-obese young males were investigated. The location of the mid-aorta between the aortic valves was used as the hydrostatic reference point for the arterial pressure measurements. It was determined by magnetic resonance (n=6) to be 7.0 +/- 0.2 cm below the sternum in SUP (1/3 of anteroposterior chest diameter below the sternum) and 2.5 +/- 0.2 cm below the midsternal level in LAT. Brachial mean (auscultation) and finger mean arterial pressures (infrared photoplethysmography), cardiac output (foreign gas rebreathing), heart rate, and plasma concentrations (n=6) of vasoactive hormones were unchanged by LAT. In conclusion, cardiac output, mean arterial pressures, and vasoactive hormone releases were unaffected by 30 min of LAT. Furthermore, the hydrostatic reference points for arterial pressure measurements is located one third of the antero-posterior chest diameter below the sternum in SUP and 2.5 cm below the midsternal level in LAT in non-obese young males.

The impact of the zona pellucida thickness variation of human embryos on pregnancy outcome in relation to suboptimal embryo development. A prospective randomized controlled study

BACKGROUND

The study represents a prospective randomized controlled study evaluating zona pellucida thickness variation (ZPTV) measurements versus conventional selection of embryos using classic embryo score criteria, prior to embryo transfer in human IVF/intracytoplasmatic sperm injection (ICSI).

METHODS

Eighty-six patients having > or =3 embryos, with a classic embryo score of < or =2.2, were allocated to either ZPTV measurement or classic embryo morphology score before embryo transfer. The technician selecting embryos using classic embryo scoring was not aware of the ZPTV measurement results. Of the embryos allocated to ZPTV measurements, only the embryos with the highest ZPTV were transferred.

RESULTS

We found no differences in the pregnancy rate per embryo transfer between the two groups (34.4 versus 35.7%). Neither did the implantation rates differ. However, significantly better results were obtained when ZPTV was used as the selection criteria in cases where all embryos had an asynchrony in development or a high embryo score (i.e. were of poorer quality) by classical evaluation (odds ratio = 2.51, confidence interval = 0.33-198).

CONCLUSIONS

Using a normally-developed embryo with an optimal embryo score, no beneficial effect of using ZPTV measurement was seen. However, when only less optimal embryos were available to select for transfer, ZPTV provided a x 2.5 increase in the chance of achieving a clinical pregnancy.

Atrial distension, arterial pulsation, and vasopressin release during negative pressure breathing in humans

During an antiorthostatic posture change, left atrial (LA) diameter and arterial pulse pressure (PP) increase, and plasma arginine vasopressin (AVP) is suppressed. By comparing the effects of a 15-min posture change from seated to supine with those of 15-min seated negative pressure breathing in eight healthy males, we tested the hypothesis that with similar increases in LA diameter, suppression of AVP release is dependent on the degree of increase in PP. LA diameter increased similarly during the posture change and negative pressure breathing (-9 to -24 mmHg) from between 30 and 31 +/- 1 to 34 +/- 1 mm (P < 0.05). The increase in PP from 38 +/- 2 to 44 +/- 2 mmHg (P < 0.05) was sustained during the posture change but only increased during the initial 5 min of negative pressure breathing from 36 +/- 3 to 42 +/- 3 mmHg (P < 0.05). Aortic transmural pressure decreased during the posture change and increased during negative pressure breathing. Plasma AVP was suppressed to a lower value during the posture change (from 1.5 +/- 0.3 to 1.2 +/- 0.2 pg/ml, P < 0.05) than during negative pressure breathing (from 1.5 +/- 0.3 to 1.4 +/- 0.3 pg/ml). Plasma norepinephrine was decreased similarly during the posture change and negative pressure breathing compared with seated control. In conclusion, the results are in compliance with the hypothesis that during maneuvers with similar cardiac distension, suppression of AVP release is dependent on the increase in PP and, furthermore, probably unaffected by static aortic baroreceptor stimulation.

Central volume expansion is pivotal for sustained decrease in heart rate during seated to supine posture change

During prolonged, static carotid baroreceptor stimulation by neck suction (NS) in seated humans, heart rate (HR) decreases acutely and thereafter gradually increases. This increase has been explained by carotid baroreceptor adaptation and/or buffering by aortic reflexes. During a posture change from seated to supine (Sup) with similar carotid stimulation, however, the decrease in HR is sustained. To investigate whether this discrepancy is caused by changes in central blood volume, we compared (n = 10 subjects) the effects of 10 min of seated NS (adjusted to simulate carotid stimulation of a posture change), a posture change from seated to Sup, and the same posture change with left atrial (LA) diameter maintained unchanged by lower body negative pressure (Sup + LBNP). During Sup, the prompt decreases in HR and mean arterial pressure (MAP) were sustained. HR decreased similarly within 30 s of NS (65 +/- 2 to 59 +/- 2 beats/min) and Sup + LBNP (65 +/- 2 to 58 +/- 2 beats/min) and thereafter gradually increased to values of seated. MAP decreased similarly within 5 min during Sup + LBNP and NS (by 7 +/- 1 to 9 +/- 1 mmHg) and thereafter tended to increase toward values of seated subjects. Arterial pulse pressure was increased the most by Sup, less so by Sup + LBNP, and was unchanged by NS. LA diameter was only increased by Sup. In conclusion, static carotid baroreceptor stimulation per se causes the acute (<30 s) decrease in HR during a posture change from seated to Sup, whereas the central volume expansion (increased LA diameter and/or arterial pulse pressure) is pivotal to sustain this decrease. Thus the effects of central volume expansion override adaptation of the carotid baroreceptors and/or buffering of aortic reflexes.

Neuroendocrine and renal effects of intravascular volume expansion in compensated heart failure

To examine if the neuroendocrine link between volume sensing and renal function is preserved in compensated chronic heart failure [HF, ejection fraction 0.29 +/- 0.03 (mean +/- SE)] we tested the hypothesis that intravascular and central blood volume expansion by 3 h of water immersion (WI) elicits a natriuresis. In HF, WI suppressed ANG II and aldosterone (Aldo) concentrations, increased the release of atrial natriuretic peptide (ANP), and elicited a natriuresis (P < 0.05 for all) compared with seated control. Compared with control subjects (n = 9), ANG II, Aldo, and ANP concentrations were increased (P < 0.05) in HF, whereas absolute and fractional sodium excretion rates were attenuated [47 +/- 16 vs. 88 +/- 15 micromol/min and 0.42 +/- 0.18 vs. 0.68 +/- 0.12% (mean +/- SE), respectively, both P < 0.05]. When ANG II and Aldo concentrations were further suppressed (P < 0.05) during WI in HF (by sustained angiotensin-converting enzyme inhibitor therapy, n = 9) absolute and fractional sodium excretion increased (P < 0.05) to the level of control subjects (108 +/- 34 micromol/min and 0.70 +/- 0.23%, respectively). Renal free water clearance increased during WI in control subjects but not in HF, albeit plasma vasopressin concentrations were similar in the two groups. In conclusion, the neuroendocrine link between volume sensing and renal sodium excretion is preserved in compensated HF. The natriuresis of WI is, however, modulated by the prevailing ANG II and Aldo concentrations. In contrast, renal free water clearance is attenuated in response to volume expansion in compensated HF despite normalized plasma AVP concentrations.

Cardiovascular effects of static carotid baroreceptor stimulation during water immersion in humans

We hypothesized that the more-pronounced hypotensive and bradycardic effects of an antiorthostatic posture change from seated to supine than water immersion are caused by hydrostatic carotid baroreceptor stimulation. Ten seated healthy males underwent five interventions of 15-min each of 1) posture change to supine, 2) seated water immersion to the Xiphoid process (WI), 3) seated neck suction (NS), 4) WI with simultaneous neck suction (−22 mmHg) adjusted to simulate the carotid hydrostatic pressure increase during supine (WI + NS), and 5) seated control. Left atrial diameter increased similarly during supine, WI + NS, and WI and was unchanged during control and NS. Mean arterial pressure (MAP) decreased the most during supine (7 ± 1 mmHg, P < 0.05) and less during WI + NS (4 ± 1 mmHg) and NS (3 ± 1 mmHg). The decrease in heart rate (HR) by 13 ± 1 beats/min ( P < 0.05) and the increase in arterial pulse pressure (PP) by 17 ± 4 mmHg ( P< 0.05) during supine was more pronounced ( P < 0.05) than during WI + NS (10 ± 2 beats/min and 7 ± 2 mmHg, respectively) and WI (8 ± 2 beats/min and 6 ± 1 mmHg, respectively, P < 0.05). Plasma vasopressin decreased only during supine and WI, and plasma norepinephrine, in addition, decreased during WI + NS ( P < 0.05). In conclusion, WI + NS is not sufficient to decrease MAP and HR to a similar extent as a 15-min seated to supine posture change. We suggest that not only static carotid baroreceptor stimulation but also the increase in PP combined with low-pressure receptor stimulation is a possible mechanism for the more-pronounced decrease in MAP and HR during the posture change.

Mechanisms of hypotensive effects of a posture change from seated to supine in humans

The hypothesis tested was that the hydrostatic stimulation of carotid baroreceptors is pivotal to decrease mean arterial pressure at heart level during a posture change from seated to supine. In eight males, the cardiovascular responses to a 15-min posture change from seated to supine were compared with those of water immersion to the xiphoid process and to the neck, respectively. Left atrial diameter and cardiac output (rebreathing) increased similarly during the posture change and water immersion to the xiphoid process and further so during neck immersion. Mean arterial pressure decreased by 12 +/- 2 mmHg during the posture change, by 5 +/- 1 mmHg during xiphoid immersion, and was unchanged during neck immersion. Arterial pulse pressure increased by 12 +/- 3 mmHg during the posture change (P < 0.05) and less during xiphoid and neck immersion by 7 +/- 3 mmHg (P < 0.05). Total peripheral vascular resistance decreased similarly during the posture change and neck immersion and slightly less during xiphoid immersion (P < 0.05). In conclusion, the hydrostatic stimulation of carotid baroreceptors combined with some additional increase in arterial pulse pressure, which also stimulates aortic baroreceptors, accounts for more than half of the hypotensive response at heart level to a posture change from seated to supine.

Pregnancy rates in relation to time intervals between repeat sperm-retrieval procedures

A total of 76 repeat sperm retrievals were carried out in 47 azoospermic men. The outcome of the procedures was evaluated regarding to the interval between two successive procedures. Sperm motility and pregnancy rate were not increased by increasing the interval between two successive sperm retrievals from less than 90 days to more than 180 days. The pregnancy rate declined from 50% with a less than 90-day interval to 25% with a more than 180-day interval. The trend did not quite reach the significance level. Pregnancy was obtained in only 27% of the couples where TESE was done the last time against 48 and 57% where PESA and TESA, respectively, were performed the last time (p < .05). This study suggests that sperm retrieval procedures in men with obstructive azoospermia can be carried out with time intervals of only 3 months to obtain an optimal pregnancy rate, and it might suggest that an epididymal aspiration procedure should be preferred for a TESE.

Unexpected renal responses in space

Urine output in astronauts following ingestion of an oral water load was low in space on the Russian space station Mir and less than during simulation by 6 degrees head-down bed rest. This surprising observation shows that the effects of gravity and weightlessness on fluid volume regulation are not well understood and that the head-down bed-rest model does not simulate the effects of weightlessness on renal water handling.

Cardiovascular and neuroendocrine responses to water immersion in compensated heart failure

The hypothesis was tested that cardiovascular and neuroendocrine (norepinephrine, renin, and vasopressin) responses to central blood volume expansion are blunted in compensated heart failure (HF). Nine HF patients [New York Heart Association class II-III, ejection fraction = 0.28 +/- 0.02 (SE)] and 10 age-matched controls (ejection fraction = 0.68 +/- 0.03) underwent 30 min of thermoneutral (34.7 +/- 0.02 degrees C) water immersion (WI) to the xiphoid process. WI increased (P < 0.05) central venous pressure by 3.7 +/- 0.6 and 3.2 +/- 0.4 mmHg and stroke volume index by 12.2 +/- 2.1 and 7.2 +/- 2.1 ml. beat(-1). m(-2) in controls and HF patients, respectively. During WI, systemic vascular resistance decreased (P < 0.05) similarly by 365 +/- 66 and 582 +/- 227 dyn. s. cm(-5) in controls and HF patients, respectively. Forearm subcutaneous vascular resistance decreased by 19 +/- 7% (P < 0.05) in controls but did not change in HF patients. Heart rate decreased less during WI in HF patients, whereas release of norepinephrine, renin, and vasopressin was suppressed similarly in the two groups. We suggest that reflex control of forearm vascular beds and heart rate is blunted in compensated HF but that baroreflex-mediated systemic vasodilatation and neuroendocrine responses to central blood volume expansion are preserved.

Low LBNP tolerance in men is associated with attenuated activation of the renin-angiotensin system

Plasma vasoactive hormone concentrations [epinephrine (p(Epi)), norepinephrine (p(NE)), ANG II (p(ANG II)), vasopressin (p(VP)), endothelin-1 (p(ET-1))] and plasma renin activity (p(RA)) were measured periodically and compared during lower body negative pressure (LBNP) to test the hypothesis that responsiveness of the renin-angiotensin system, the latter being one of the most powerful vasoconstrictors in the body, is of major importance for LBNP tolerance. Healthy men on a controlled diet (2,822 cal/day, 2 mmol. kg(-1). day(-1) Na(+)) were exposed to 30 min of LBNP from -15 to -50 mmHg. LBNP was uneventful for seven men [25 +/- 2 yr, high-tolerance (HiTol) group], but eight men (26 +/- 3 yr) reached presyncope after 11 +/- 1 min [P < 0.001, low-tolerance (LoTol) group]. Mean arterial pressure (MAP) did not change measurably, but central venous pressure and left atrial diameter decreased similarly in both groups (5-6 mmHg, by approximately 30%, P < 0.05). Control (0 mmHg LBNP) hormone concentrations were similar between groups, however, p(RA) differed between them (LoTol 0.6 +/- 0.1, HiTol 1.2 +/- 0.1 ng ANG I. ml(-1). h(-1), P < 0.05). LBNP increased (P < 0. 05) p(RA) and p(ANG II), respectively, more in the HiTol group (9.9 +/- 2.2 ng ANG I. ml(-1). h(-1) and 58 +/- 12 pg/ml) than in LoTol subjects (4.3 +/- 0.9 ng ANG I. ml(-1). h(-1) and 28 +/- 6 pg/ml). In contrast, the increase in p(VP) was higher (P < 0.05) in the LoTol than in the HiTol group. The increases (P < 0.05) for p(NE) were nonsignificant between groups, and p(ET-1) remained unchanged. Thus there may be a causal relationship between attenuated activation of p(RA) and p(ANG II) and presyncope, with p(VP) being a possible cofactor. Measurement of resting p(RA) may be of predictive value for those with lower hypotensive tolerance.

Influence of zona pellucida thickness of human embryos on clinical pregnancy outcome following in vitro fertilization treatment

PURPOSE

To evaluate the correlation between the degree of zona pellucida thickness variation (ZPTV) of transferred embryos with identical morphologies and subsequent clinical pregnancy rates during 141 intracytoplasmic sperm injection (ICSI) treatment cycles.

METHODS

A total of 141 women participating in the study group comprising mostly male factor infertilities and some repeat in vitro fertilization (IVF) failures were transferred, 2 days after ovum pickup, with two to three embryos with identical grades created by fertilization with ICSI. All selected embryos were subjected to zona pellucida thickness measurements immediately prior to transfer using a computerized embryo measurement program from videocinematography recordings.

RESULTS

A total of 326 identical-grade transferred pre-embryos resulted in 70 clinical pregnancies with live-born implantation rate of 27.6%. A highly significant correlation was observed between ZPTV of transferred embryos and the IVF outcome with 77.1% and 83.64% of the clinical pregnancies resulting from transferred embryos with ZPTV values greater than 20 and 25, respectively. The mean ZPTV values for 70 conceptual cycles and 62 nonconceptual cycles were 28 +/- 6.43 and 17.85 +/- 8.11, respectively. No significant correlation between ZP thickness and number of blastomeres in the transferred embryos was evident, though embryos with better scores had significantly thinner zonae and higher ZPTV values. Though average zona thickness of embryos declined with age, the mean ZPTV value for women less than 30 years old was significantly higher (25.84 +/- 8.57) as compared with those from women older than 35 years (20.72 +/- 8.45).

CONCLUSIONS

The degree of ZPTV of the transferred embryos exhibits a strong correlation with clinical pregnancy outcome following IVF treatment. This potentially reliable indicator of IVF success rate could be used as a criteria for embryo selection during clinical transfers.

Forearm vascular and neuroendocrine responses to graded water immersion in humans

The hypothesis that graded expansion of central blood volume by water immersion to the xiphoid process and neck would elicit a graded decrease in forearm vascular resistance was tested. Central venous pressure increased (P < 0.05) by 4.2 +/- 0.4 mmHg (mean +/- SEM) during xiphoid immersion and by 10.4 +/- 0.5 mmHg during neck immersion. Plasma noradrenaline was gradually suppressed (P < 0.05) by 62 +/- 8 and 104 +/- 11 pg mL-1 during xiphoid and neck immersion, respectively, indicating a graded suppression of sympathetic nervous activity. Plasma concentrations of arginine vasopressin were suppressed by 1.5 +/- 0.5 pg mL-1 (P < 0.05) during xiphoid immersion and by 2.0 +/- 0.5 pg mL-1 during neck immersion (P < 0.05 vs. xiphoid immersion). Forearm subcutaneous vascular resistance decreased to the same extent by 26 +/- 9 and 28 +/- 4% (P < 0.05), respectively, during both immersion procedures, whereas forearm skeletal muscle vascular resistance declined only during neck immersion by 27 +/- 6% (P < 0.05). In conclusion, graded central blood volume expansion initiated a graded decrease in sympathetic nervous activity and AVP-release. Changes in forearm subcutaneous vascular resistance, however, were not related to the gradual withdrawal of the sympathetic and neuroendocrine vasoconstrictor activity. Forearm skeletal muscle vasodilatation exhibited a more graded response with a detectable decrease only during immersion to the neck. Therefore, the forearm subcutaneous vasodilator response reaches saturation at a lower degree of central volume expansion than that of forearm skeletal muscle.

Arterial pulse pressure and vasopressin release during graded water immersion in humans

Previous results indicate that arterial pulse pressure modulates release of arginine vasopressin (AVP) in humans. The hypothesis was therefore tested that an increase in arterial pulse pressure is the stimulus for suppression of AVP release during central blood volume expansion by water immersion. A two-step immersion model (n = 8) to the xiphoid process and neck, respectively, was used to attain two different levels of augmented cardiac distension. Left atrial diameter (echocardiography) increased from 28 +/- 1 to 34 +/- 1 mm (P < 0.05) during immersion to the xiphoid process and more so (P < 0.05), to 36 +/- 1 mm, during immersion to the neck. During immersion to the xiphoid process, arterial pulse pressure (invasively measured in a brachial artery) increased (P < 0.05) from 44 +/- 1 to 51 +/- 2 mmHg and to the same extent from 42 +/- 1 to 52 +/- 2 mmHg during immersion to the neck. Mean arterial pressure was unchanged during immersion to the xiphoid process and increased during immersion to the neck by 7 +/- 1 mmHg (P < 0.05). Arterial plasma AVP decreased from 2.5 +/- 0.7 to 1.8 +/- 0.5 pg/ml (P < 0. 05) during immersion to the xiphoid process and significantly more so (P < 0.05), to 1.4 +/- 0.5 pg/ml, during immersion to the neck. In conclusion, other factors besides the increase in arterial pulse pressure must have participated in the graded suppression of AVP release, comparing immersion to the xiphoid process with immersion to the neck. We suggest that when arterial pulse pressure is increased, graded distension of cardiopulmonary receptors modulate AVP release.

Contribution of the leg vasculature to hypotensive effects of an antiorthostatic posture change in humans

1. Previous results from our laboratory have shown that vasodilatation in the legs prevents mean arterial pressure (MAP) from increasing during water immersion. Therefore, we tested the hypothesis that vasodilatation in the legs is necessary for the hypotensive effects to occur during a moderate antiorthostatic posture change. 2. Ten healthy males underwent a 5 min posture change from upright seated to horizontal supine (SUP) and back to seated again with (OCCL-SUP) and without simultaneous total arterial (154 +/- 1 mmHg) thigh occlusion, and a control seated period, also with and without arterial occlusion. Cardiac output (CO) was measured by a non-invasive foreign (N2O) gas rebreathing technique. 3. MAP (brachial auscultation) decreased during SUP from 94 +/- 3 to 84 +/- 2 mmHg (P < 0.0001) and total peripheral vascular resistance (TPR = MAP/CO, n = 8) decreased by 15 +/- 4 % (P < 0.001). During OCCL-SUP, MAP decreased from 98 +/- 2 to 90 +/- 2 mmHg (P < 0.005) and TPR decreased by 14 +/- 3 % (P < 0.01). 4. In conclusion, vasodilatation in the legs is not necessary for the decrease in MAP to occur during a moderate antiorthostatic manoeuvre. Therefore, vasodilatation in more central vascular beds (e.g. abdomen) can alone account for the hypotensive effects.

Arterial pressure in humans during weightlessness induced by parabolic flights

Results from our laboratory have indicated that, compared with those of the 1-G supine (Sup) position, left atrial diameter (LAD) and transmural central venous pressure increase in humans during weightlessness (0 G) induced by parabolic flights (R. Videbaek and P. Norsk. J. Appl. Physiol. 83: 1862-1866, 1997). Therefore, because cardiopulmonary low-pressure receptors are stimulated during 0 G, the hypothesis was tested that mean arterial pressure (MAP) in humans decreases during 0 G to values below those of the 1-G Sup condition. When the subjects were Sup, 0 G induced a decrease in MAP from 93 +/- 4 to 88 +/- 4 mmHg (P < 0.001), and LAD increased from 30 +/- 1 to 33 +/- 1 mm (P < 0.001). In the seated position, MAP also decreased from 93 +/- 6 to 87 +/- 5 mmHg (P < 0.01) and LAD increased from 28 +/- 1 to 32 +/- 1 mm (P < 0.001). During 1-G conditions with subjects in the horizontal left lateral position, LAD increased compared with that of Sup (P < 0.001) with no further effects of 0 G. In conclusion, MAP decreases during short-term weightlessness to below that of 1-G Sup simultaneously with an increase in LAD. Therefore, distension of the heart and associated central vessels during 0 G might induce the hypotensive effects through peripheral vasodilatation. Furthermore, the left lateral position in humans could constitute a simulation model of weightlessness.

A Danish national cohort of 730 infants born after intracytoplasmic sperm injection (ICSI) 1994-1997

This national cohort study included all clinical pregnancies obtained after intracytoplasmic sperm injection (ICSI) registered in Denmark between January 1994 and July 1997 at five public and eight private fertility clinics. Laboratory and clinical data were obtained from the fertility clinics. The couples answered a questionnaire regarding the pregnancy and the health of the child (response rate 94%). Data validation was carried out through discharge charts. The mean age of the women was 32.1 years. In 84.2% of couples, male factor was the main reason for performing ICSI, and in 4.8% epididymal spermatozoa were used. The mean number of embryos replaced was 2.3 (range 1-3) and in 95% of cases fresh embryos were transferred. Only 183 women (28.5%) underwent prenatal diagnosis, resulting in 209 karyotypes with seven (3.3%) chromosome aberrations. Six major chromosomal abnormalities (2.9%) and one inherited structural chromosome aberration (0.5%) were found, but no sex chromosome aberrations. The frequency of multiple birth, Caesarean section rate, gestational age, preterm birth, and birth weight were comparable with previous studies. The perinatal mortality rate was 13.7 per 1000 children born with a gestational age of 24 weeks or more. In 2.2% (n = 16) of the liveborn infants, and in 2.7% (n = 20) of all infants, major birth defects were reported by the parents. Minor birth defects were found in nine liveborn infants (1.2%). In conclusion, the results of this study on outcome of ICSI pregnancies are in line with earlier reports, except that no sex chromosome abnormalities were found.

Mechanisms of inhibition of vasopressin release during moderate antiorthostatic posture change in humans

The hypothesis was tested that the carotid baroreceptor stimulation caused by a posture change from upright seated with legs horizontal (Seat) to supine (Sup) participates in the suppression of arginine vasopressin (AVP) release. Ten healthy males underwent this posture change for 30 min without or with simultaneous application of lower body negative pressure (LBNP) adjusted to maintain left atrial diameter (LAD) at the Seat level. Throughout Sup, mean arterial pressure and heart rate decreased from 98 +/- 2 to 91 +/- 2 mmHg and from 63 +/- 2 to 55 +/- 2 beats/min (P < 0.05), respectively, whereas the corresponding decreases during Sup + LBNP were attenuated and of shorter duration (98 +/- 2 to 93 +/- 2 mmHg and 62 +/- 2 to 58 +/- 3 beats/min, P < 0.05). During Sup, LAD increased from 30 +/- 1 to 33 +/- 1 mm, and arterial pulse pressure (PP) increased from 40 +/- 2 to 47 +/- 2 mmHg, whereas plasma AVP decreased from 0.9 +/- 0.2 to 0.5 +/- 0.1 pg/ml (P < 0.05), and plasma norepinephrine (NE) decreased from 176 +/- 20 to 125 +/- 16 pg/ml (P < 0.05). During Sup + LBNP, there were no changes in LAD, PP, plasma AVP, or NE. In conclusion, vasopressin secretion is suppressed during an antiorthostatic posture change, which increases carotid sinus pressure, PP, and LAD. The suppression is absent when PP and LAD are prevented from increasing and is thus critically dependent on at least one of these stimuli.

Preservation of veno-arteriolar reflex in the skin following 20 days of head down bed rest in humans

A decrease in orthostatic tolerance following exposure to microgravity or head down bed rest (HDBR) is frequently observed and is thought to be multifactorial in origin. Recently published observations by Buckey et al. indicate that the inability to regulate peripheral vascular resistance during an orthostatic stress after spaceflight could be another important mechanism for orthostatic intolerance. Previous investigations have revealed that a local veno-arteriolar reflex is present in cutaneous, subcutaneous and muscle tissue. The reflex response is elicited in response to an increase in transmural venular pressure of about 25 mmHg or more. The local veno-arteriolar reflex acts in concert with centrally elicited sympathetic activity to regulate vascular resistance. During standing, the local veno-arteriolar reflex participates as a mechanism to increase peripheral vascular resistance independently of sympathetically mediated vasoconstrictor responses. During HDBR the local veno-arteriolar reflex is inactive for a prolonged period of time. Therefore we hypothesized that the veno-arteriolar reflex in the skin is attenuated immediately after prolonged HDBR and that an attenuation of the response may contribute to post-HDBR orthostatic intolerance.