Central-line-associated bloodstream infection burden among Dutch neonatal intensive care units.

BACKGROUND: The establishment of an epidemiological overview provides valuable insights needed for the (future) dissemination of infection-prevention initiatives. AIM: To describe the nationwide epidemiology of central-line-associated bloodstream infections (CLABSI) among Dutch Neonatal Intensive Care Units (NICUs). METHODS: Data from 2935 neonates born at <32 weeks' gestation and/or with a birth weight <1500 g admitted to all nine Dutch NICUs over a two-year surveillance period (2019-2020) were analysed. Variations in baseline characteristics, CLABSI incidence per 1000 central-line days, pathogen distribution and CLABSI care bundles were evaluated. Multi-variable logistic mixed-modelling was used to identify significant predictors for CLABSI. RESULTS: A total of 1699 (58%) neonates received a central line, in which 160 CLABSI episodes were recorded. Coagulase-negative staphylococci were the most common infecting organisms of all CLABSI episodes (N=100, 63%). An almost six-fold difference in the CLABSI incidence between participating units was found (2.91-16.14 per 1000 line-days). Logistic mixed-modelling revealed longer central line dwell-time (adjusted odds ratio (aOR):1.08, P<0.001), umbilical lines (aOR:1.85, P=0.03) and single rooms (aOR:3.63, P=0.02) to be significant predictors of CLABSI. Variations in bundle elements included intravenous tubing care and antibiotic prophylaxis. CONCLUSIONS: CLABSI remains a common problem in preterm infants in The Netherlands, with substantial variation in incidence between centres. Being the largest collection of data on the burden of neonatal CLABSI in The Netherlands, this epidemiological overview provides a solid foundation for the development of a collaborative platform for continuous surveillance, ideally leading to refinement of national evidence-based guidelines. Future efforts should focus on ensuring availability and extraction of routine patient data in aggregated formats.

Linking the Mechanics of Chewing to Biology of the Junctional Epithelium.

The capacity of a tissue to continuously alter its phenotype lies at the heart of how an animal is able to quickly adapt to changes in environmental stimuli. Within tissues, differentiated cells are rigid and play a limited role in adapting to new environments; however, differentiated cells are replenished by stem cells that are defined by their phenotypic plasticity. Here we demonstrate that a Wnt-responsive stem cell niche in the junctional epithelium is responsible for the capability of this tissue to quickly adapt to changes in the physical consistency of a diet. Mechanical input from chewing is required to both establish and maintain this niche. Since the junctional epithelium directly attaches to the tooth surface via hemidesmosomes, a soft diet requires minimal mastication, and consequently, lower distortional strains are produced in the tissue. This reduced strain state is accompanied by reduced mitotic activity in both stem cells and their progeny, leading to tissue atrophy. The atrophied junctional epithelium exhibits suboptimal barrier functions, allowing the ingression of bacteria into the underlying connective tissues, which in turn trigger inflammation and mild alveolar bone loss. These data link the mechanics of chewing to the biology of tooth-supporting tissues, revealing how a stem cell niche is responsible for the remarkable adaptability of the junctional epithelium to different diets.

Clinical and self-reported markers of reproductive function in female survivors of childhood Hodgkin lymphoma.

PURPOSE: To evaluate the impact of treatment for Hodgkin lymphoma (HL) on clinical reproductive markers and pregnancy outcomes. METHODS: This study was embedded within the DCOG LATER-VEVO study; a Dutch, multicenter, retrospective cohort study between 2004 and 2014. Serum anti-Müllerian hormone (AMH), follicle stimulating hormone (FSH), inhibin B, antral follicle count (AFC), and self-reported (first) pregnancy outcomes were evaluated in female childhood HL survivors and controls. RESULTS: 84 HL survivors and 798 controls were included, aged 29.6 and 32.7 years old at time of assessment. Median age at HL diagnosis was 13.4 years. Cyclophosphamide equivalent dose (CED-score) exceeded 6000 mg/m2 in 56 women and 14 survivors received pelvic irradiation. All clinical markers were significantly deteriorated in survivors (odds-ratio for low AMH (< p10) 10.1 [95% CI 4.9; 20.6]; low AFC (< p10) 4.6 [95% CI 2.1; 9.9]; elevated FSH (> 10 IU/l) 15.3 [95% CI 5.7; 41.1], low Inhibin B (< 20 ng/l) 3.6 [ 95% CI 1.7; 7.7], p < 0.001). Pregnancy outcomes were comparable between survivors and controls (± 80% live birth, ± 20% miscarriage). However, survivors were significantly younger at first pregnancy (27.0 years vs 29.0 years, P = 0.04). Adjusted odds-ratio for time to pregnancy > 12 months was 2.5 [95% CI 1.1; 5.6] in survivors, p = 0.031. Adverse outcomes were specifically present after treatment with procarbazine and higher CED-score. CONCLUSION: HL survivors appear to have an impaired ovarian reserve. However, chance to achieve pregnancy seems reassuring at a young age. Additional follow-up studies are needed to assess fertile life span and reproductive potential of HL survivors, in particular for current HL treatments that are hypothesized to be less gonadotoxic.

The circadian dynamics of the hippocampal transcriptome and proteome is altered in experimental temporal lobe epilepsy.

Gene and protein expressions display circadian oscillations, which can be disrupted in diseases in most body organs. Whether these oscillations occur in the healthy hippocampus and whether they are altered in epilepsy are not known. We identified more than 1200 daily oscillating transcripts in the hippocampus of control mice and 1600 in experimental epilepsy, with only one-fourth oscillating in both conditions. Comparison of gene oscillations in control and epilepsy predicted time-dependent alterations in energy metabolism, which were verified experimentally. Although aerobic glycolysis remained constant from morning to afternoon in controls, it increased in epilepsy. In contrast, oxidative phosphorylation increased in control and decreased in epilepsy. Thus, the control hippocampus shows circadian molecular remapping, which is altered in epilepsy. We suggest that the hippocampus operates in a different functioning mode in epilepsy. These alterations need to be considered when studying epilepsy mechanisms, designing drug treatments, and timing their delivery.

Does AMH relate to timing of menopause? Results of an Individual Patient Data meta- analysis.

CONTEXT: Anti-Müllerian hormone based (AMH) age at menopause predictions remain cumbersome due to predictive inaccuracy. OBJECTIVE: To perform an Individual Patient Data (IPD) meta-analysis, regarding AMH based menopause prediction. DATA SOURCES: A systematic literature search was performed using PubMed, Embase and Cochrane databases. STUDY SELECTION: Prospective cohort studies regarding menopause prediction using serum AMH levels were selected by consensus discussion. DATA SELECTION: Individual cases were included if experiencing a regular cycle at baseline. Exclusion criteria were hormone use and gynecological surgery. DATA SYNTHESIS: 2596 women were included, 1077 experienced menopause. A multivariable Cox regression analysis assessed time to menopause (TTM) using age and AMH. AMH predicted TTM, however, added value on top of age was poor (age alone C-statistic 84%; age + AMH HR 0.66 95% CI 0.61-0.71, C-statistic 86%). Moreover, the capacity of AMH to predict early (≤45 years) and late menopause (≥55 years) was assessed. An added effect of AMH was demonstrated for early menopause (age alone C-statistic 52%; age + AMH HR 0.33, 95% CI 0.24-0.45, C-statistic 80%). A Weibull regression model calculating individual age at menopause revealed that predictive inaccuracy remained present and increased with decreasing age at menopause. Lastly, a check of non-proportionality of the predictive effect of AMH demonstrated a reduced predictive effect with increasing age. CONCLUSION: AMH was a significant predictor of TTM and especially of time to early menopause. However, individual predictions of age at menopause demonstrated a limited precision, particularly when concerning early age at menopause, making clinical application troublesome.

Anti-Müllerian hormone does not predict time to pregnancy: results of a prospective cohort study.

In order to study whether ovarian reserve tests (ORTs) can predict time to ongoing pregnancy, we conducted a prospective cohort study in a cohort of healthy pregnancy planners. A total of 102 pregnancy planners were followed for 1 year, or until ongoing pregnancy occurred, after cessation of contraceptives). A baseline measurement of anti-Müllerian hormone (AMH), follicle-stimulating hormone (FSH) and antral follicle count (AFC) was conducted. At the end of follow-up, a semen analysis was performed and chlamydia antibody titres were assessed. A univariate prediction model demonstrated age and the AFC to be significantly capable of predicting time to pregnancy (hazard ratio 0.92, 95% CI 0.87-0.98, p = 0.01; 1.04, 95% CI 1.01-1.07, p = 0.02 respectively). In the multivariate model, however, correcting for female age, we found no predictive effect of AMH, basal FSH or the AFC for time to ongoing pregnancy (hazard ratios 1.43, 95% CI 0.84-2.46, p = 0.36; 0.96, 95% CI 0.86-1.06, p = 0.43; 1.03, 95% CI 1.00-1.07, p = 0.08, respectively). This was confirmed by the low C-statistic. We therefore concluded that baseline AMH, AFC or FSH levels do not predict time to ongoing pregnancy in a cohort of healthy pregnancy planners. These results limit the usability of these ORTs in the assessment of current fertility.

Does anti-Müllerian hormone predict menopause in the general population? Results of a prospective ongoing cohort study.

STUDY QUESTION: Do ovarian reserve tests (ORTs) predict age at natural menopause (ANM) in a cohort of healthy women with a regular menstrual cycle? SUMMARY ANSWER: Of the ORTs researched, anti-Müllerian hormone (AMH) alone predicts age at menopause. However, its predictive value decreased with increasing age of the woman, prediction intervals were broad and extreme ages at menopause could not be predicted. WHAT IS KNOWN ALREADY: A fixed interval is hypothesized to exist between ANM and age at loss of natural fertility. Therefore, if it is possible to predict ANM, one could identify women destined for early menopause and thus at higher risk for age-related subfertility. Of ORTs researched in the prediction of ANM, AMH is the most promising one. STUDY DESIGN, STUDY SIZE AND DURATION: A long-term, extended follow-up study was conducted, results of the first follow-up round were previously published. Two hundred and sixty-five normo-ovulatory women (21-46 years) were included between 1992 and 2001, 49 women (18.5%) could not be reached in the current follow-up round. PARTICIPANTS, SETTING, METHODS: Two hundred and sixty-five healthy normo-ovulatory women were included, recruited in an Academic hospital. We measured baseline AMH, follicle-stimulating hormone and the antral follicle count (AFC). At follow-up (2009 and 2013), menopausal status was determined via questionnaires. Cox regression analysis calculated time to menopause (TTM) using age and ORT. A check of (non-) proportionality of the predictive effect of AMH was performed. A Weibull survival model was used in order to predict individual ANM. MAIN RESULTS AND THE ROLE OF CHANCE: In total, 155 women were available for analyses. Eighty-one women (37.5%) had become post-menopausal during follow-up. Univariable Cox regression analysis demonstrated age and ORTs to be significantly correlated with TTM. Multivariable Cox regression analysis, adjusting for baseline age and smoking; however, demonstrated AMH alone to be an independent predictor of TTM (Hazard Ratio 0.70, 95% Confidence Interval 0.56-0.86, P-value <0.001). A (non-)proportionality analysis of AMH over time demonstrated AMH's predictive effect to decline over time. LIMITATIONS, REASON FOR CAUTION: The observed predictive effect of AMH became less strong with increasing age of the woman. Individual AMH-based age at menopause predictions did not cover the full range of menopausal ages, but did reduce the variation around the predicted ANM from 20 to 10.1 years. WIDER IMPLICATIONS OF THE FINDINGS: Age-specific AMH levels are predictive for ANM. Unlike in our previous publication however, a declining AMH effect with increasing age was observed. This declining AMH effect is in line with recent long-term follow-up data published by others. Moreover, the accompanying predictive inaccuracy observed in individual age at menopause predictions based on AMH, makes this marker currently unsuitable for use in clinical practice. STUDY FUNDING/COMPETING INTERESTS: No external funds were used for this study. M.D., M.J.C.E, S.L.B., G.J.S. and I.A.J.R. have nothing to declare. J.S.E.L. has received fees and grant support from the following companies (in alphabetical order): Ferring, Merck-Serono, MSD, Organon, Serono and Schering Plough. F.J.M.B. receives monetary compensation: member of the external advisory board for Merck Serono, the Netherlands; consultancy work for Gedeon Richter, Belgium; educational activities for Ferring BV, the Netherlands; strategic cooperation with Roche on automated AMH assay development.

The Relationship Between Variation in Size of the Primordial Follicle Pool and Age at Natural Menopause.

CONTEXT: Menopause has been hypothesized to occur when the nongrowing follicle (NGF) number falls below a critical threshold. Age at natural menopause can be predicted using NGF numbers and this threshold. These predictions support the use of ovarian reserve tests, reflective of the ovarian follicle pool, in menopause forecasting. OBJECTIVE: The objective of the study was to investigate the hypothesis that age-specific NGF numbers reflect age at natural menopause. DESIGN AND SETTING: Histologically derived NGF numbers obtained from published literature (n = 218) and distribution of menopausal ages derived from the population-based Prospect-European Prospective Investigation into Cancer and Nutrition (Prospect-EPIC) cohort (n = 4037) were combined. PARTICIPANTS: NGF data were from single ovaries that had been obtained postnatally for various reasons, such as elective surgery or autopsy. From the Prospect-EPIC cohort, women aged 58 years and older with a known age at natural menopause were selected. INTERVENTIONS: There were no interventions. MAIN OUTCOME MEASURE(S): Conformity between observed age at menopause in the Prospect-EPIC cohort and NGF-predicted age at menopause from a model for age-related NGF decline constructed using a robust regression analysis. A critical threshold for NGF number was estimated by comparing the probability distribution of the age at which the NGF numbers fall below this threshold with the observed distribution of age at natural menopause from the Prospect-EPIC cohort. RESULTS: The distributions of observed age at natural menopause and predicted age at natural menopause showed close conformity. CONCLUSION: The close conformity observed between NGF-predicted and actual age at natural menopause supports the hypothesis that that the size of the primordial follicle pool is an important determinant for the length of the individual ovarian life span and supports the concept of menopause prediction using ovarian reserve tests, such as anti-Müllerian hormone and antral follicle count, as derivatives of the true ovarian reserve.

Predicting menopausal age with anti-Müllerian hormone: a cross-validation study of two existing models.

OBJECTIVE: This study aimed to cross-validate two comparable Weibull models of prediction of age at natural menopause from two cohorts, the Scheffer, van Rooij, de Vet (SRV) cohort and the Tehran Lipid and Glucose Study (TLGS) cohort. It summarizes advantages and disadvantages of the models and underlines the need for achieving correct time dependency in dynamic variables like anti-Müllerian hormone. METHODS: Models were fitted in the original datasets and then applied to the cross-validation datasets. The discriminatory capacity of each model was assessed by calculating C-statistics for the models in their own data and in the cross-validation data. Calibration of the models on the cross-validation data was assessed by measuring the slope, intercept and Weibull shape parameter. RESULTS: The C-statistic for the SRV model on the SRV data was 0.7 (95% confidence interval (CI) 0.7-0.8) and on the TLGS data it was 0.8 (95% CI 0.8-0.9). For the TLGS model on the TLGS data, it was 0.9 (95% CI 0.8-0.9) and on the SRV data it was 0.7 (95% CI 0.6-0.8). After calibration of the SRV model on the TLGS data, the slope was 1, the intercept -0.3 and the shape parameter 1.1. The TLGS model on the SRV data had a slope of 0.3, an intercept of 12.7 and a shape parameter of 0.6. CONCLUSIONS: Both models discriminate well between women that enter menopause early or late during follow-up. While the SRV model showed good agreement between the predicted risk of entering menopause and the observed proportion of women who entered menopause during follow-up (calibration) in the cross-validation dataset, the TLGS model showed poor calibration.

Anti-Mullerian hormone is a more accurate predictor of individual time to menopause than mother's age at menopause.

STUDY QUESTION: In the prediction of time to menopause (TTM), what is the added value of anti-Müllerian hormone (AMH) when mother's age at natural menopause (ANM) is also known? SUMMARY ANSWER: AMH is a more accurate predictor of individual TTM than mother's age at menopause. WHAT IS KNOWN ALREADY: Mother's ANM is considered a proxy for daughter's ANM although studies on its predictive accuracy are non-existent. AMH is a biomarker with a known capacity to predict ANM. However, its added value on top of known predictors, like mother's ANM, is unknown. STUDY DESIGN, SIZE, DURATION: Population-based cohort studies were used. To assess any additive predictive value of mother's ANM, 164 mother-daughter pairs were used (Group 1). To assess the added value of AMH, a second group of 150 women in whom AMH and mother's ANM were recorded prior to a 12-year follow-up period during which daughter's ANM was assessed was used (Group 2). PARTICIPANTS/MATERIALS, SETTING, METHODS: Group 1 consisted of participants of the DOM cohort (an ongoing breast cancer study). Group 2 was a pooled cohort of women with regular menstrual cycles from two independent published studies. Cox proportional hazards analysis estimated uni- and multivariate regression coefficients for female age at study entry, mother's ANM and AMH in the prediction of TTM. Discrimination of models was assessed with C-statistics. Clinical added value of AMH was quantified with a net reclassification index (NRI). MAIN RESULTS AND THE ROLE OF CHANCE: A model with female age and mother's ANM had a c-statistic of 79 and 85% in groups 1 and 2, respectively. Both age and mother's ANM were significantly associated with TTM (HR 1.54 and HR 0.93 for age and mother's ANM in Cohort 1 and HR 1.59 and HR 0.89 in Group 2, respectively. P-value for all <0.001). In Group 2, the multivariate model with age, mother's ANM and AMH had a c-statistic of 92%, and only female age and AMH remained significantly associated with TTM (HR 1.41 P < 0.0001; HR 0.93 P = 0.08 and HR 0.06 P < 0.0001 for age, mother's ANM and AMH, respectively). The mean weighted NRI suggests that a 47% improvement in predictive accuracy is offered by adding AMH to the model of age and mother's ANM. In conclusion, AMH and mother's ANM both have added value in forecasting TTM for the daughter based on her age. In comparison, AMH is a more accurate added predictor of TTM than mother's ANM. LIMITATIONS, REASONS FOR CAUTION: The cohort of women is relatively small and different cohorts of women were pooled. WIDER IMPLICATIONS OF THE FINDINGS: This study shows that AMH is a more accurate predictor of ANM than mother's ANM. However, before achieving clinical applicability, the certainty with which a woman's prediction is made must improve. The association between mother's ANM and TTM in daughters did not appear to be influenced by whether ANM was recorded by mothers or daughters--an important finding because in the clinical setting daughters usually provide this information. STUDY FUNDING/COMPETING INTEREST(S): No funding was received and there were no competing interests in direct relation to this study.

Proconvulsant actions of intrahippocampal botulinum neurotoxin B in the rat.

Botulinum neurotoxins (BoNTs) may affect the excitability of brain circuits by inhibiting neurotransmitter release at central synapses. There is evidence that local delivery of BoNT serotypes A and E, which target SNAP-25, a component of the release machinery specific to excitatory synapses, can inhibit seizure generation. BoNT serotype B (BoNT/B) targets VAMP2, which is expressed in both excitatory and inhibitory terminals. Here we assessed the effects of unilateral intrahippocampal infusion of BoNT/B in the rat on intravenous pentylenetetrazol (PTZ) seizure thresholds, and on the expression of spontaneous behavioral and electrographic seizures. Infusion of BoNT/B (500 and 1,000 unit) by convection-enhanced delivery caused a reduction in myoclonic twitch and clonic seizure thresholds in response to intravenous PTZ beginning about 6 days after the infusion. Handling-evoked and spontaneous convulsive seizures were observed in many BoNT/B-treated animals but not in vehicle-treated controls. Spontaneous electrographic seizure discharges were recorded in the dentate gyrus of animals that received local BoNT/B infusion. In addition, there was an increased frequency of interictal epileptiform spikes and sharp waves at the same recording site. BoNT/B-treated animals also exhibited tactile hyperresponsivity in comparison with vehicle-treated controls. This is the first demonstration that BoNT/B causes a delayed proconvulsant action when infused into the hippocampus. Local infusion of BoNT/B could be useful as a focal epilepsy model.

The Concise Guide to PHARMACOLOGY 2013/14: overview.

The Concise Guide to PHARMACOLOGY 2013/14 provides concise overviews of the key properties of over 2000 human drug targets with their pharmacology, plus links to an open access knowledgebase of drug targets and their ligands (www.guidetopharmacology.org), which provides more detailed views of target and ligand properties from the IUPHAR database. The full contents can be found at http://onlinelibrary.wiley.com/doi/10.1111/bph.12444/full. This compilation of the major pharmacological targets is divided into seven areas of focus: G protein-coupled receptors, ligand-gated ion channels, ion channels, catalytic receptors, nuclear hormone receptors, transporters and enzymes. These are presented with nomenclature guidance and summary information on the best available pharmacological tools, alongside key references and suggestions for further reading. A new landscape format has easy to use tables comparing related targets. It is a condensed version of material contemporary to late 2013, which is presented in greater detail and constantly updated on the website www.guidetopharmacology.org, superseding data presented in previous Guides to Receptors & Channels. It is produced in conjunction with NC-IUPHAR and provides the official IUPHAR classification and nomenclature for human drug targets, where appropriate. It consolidates information previously curated and displayed separately in IUPHAR-DB and GRAC and provides a permanent, citable, point-in-time record that will survive database updates.

The poor responder in IVF: is the prognosis always poor?: a systematic review.

BACKGROUND In IVF treatment a considerable proportion of women are faced with a low number of oocytes retrieved. These poor responders have reduced pregnancy rates compared with normal responders. However, this may not be applicable to all poor responders. This review aims at identifying patient characteristics and ovarian reserve tests (ORT) that will determine prognosis for pregnancy in poor responders. METHODS A systematic search was conducted in PubMed, Embase, Cochrane and SCOPUS databases in April 2010. Studies regarding patient characteristics or ORT in poor responders and their pregnancy prospects were included. All included papers were summarized in descriptive tables. RESULTS Nineteen studies were included. Pooled data of six studies comparing poor and normal responders demonstrated clearly lower pregnancy rates in poor responders (14.8 versus 34.5%). Ten studies indicated that older poor responders have a lower range of pregnancy rates compared with younger (1.5-12.7 versus 13.0-35%, respectively). Four studies showed that pregnancy prospects become reduced when fewer oocytes are retrieved (0-7% with 1 oocyte versus 11.5-18.6% with 4 oocytes). Five studies concerning pregnancy rates in subsequent cycles suggested a more favourable outcome in unexpected poor responders, and if ≥2 oocytes were retrieved. CONCLUSIONS Poor responders are not a homogeneous group of women with regards to pregnancy prospects. Female age and number of oocytes retrieved in particular will modulate the chances for pregnancy in current and subsequent cycles. Applying these criteria will allow the identification of couples with a reasonable prognosis and balanced decision-making on the management of poor responders.

Anti-mullerian hormone predicts menopause: a long-term follow-up study in normoovulatory women.

CONTEXT: It has been hypothesized that a fixed interval exists between age at natural sterility and age at menopause. Both events show considerable individual variability, with a range of 20 yr. Correct prediction of age at menopause could open avenues of individualized prevention of age-related infertility and other menopause-related conditions, like cardiovascular disease and breast carcinoma. OBJECTIVE: The aim of this study was to explore the ability of ovarian reserve tests to predict age at menopause. DESIGN AND SETTING: We conducted a long-term follow-up study at an academic hospital. PARTICIPANTS: A total of 257 normoovulatory women (age, 21-46 yr) were derived from three cohorts with highly comparable selection criteria. INTERVENTIONS: Anti-Müllerian hormone (AMH), antral follicle count, and FSH were assessed at time 1 (T1). At time 2 (T2), approximately 11 yr later, cycle status (strictly regular, menopausal transition, or postmenopause) and age at menopause were inventoried. MAIN OUTCOME MEASURES: Accuracy of the ovarian reserve tests in predicting time to menopause was assessed by Cox regression, and a nomogram was constructed for the relationship between age-specific AMH concentrations at T1 and age at menopause. RESULTS: A total of 48 (19%) women had reached postmenopause at T2. Age, AMH, and antral follicle count at T1 were significantly related with time to menopause (P < 0.001) and showed a good percentage of correct predictions (C-statistic, 0.87, 0.86, and 0.84, respectively). After adjusting for age, only AMH added to this prediction (C-statistic, 0.90). From the constructed nomogram, it appeared that the normal distribution of age at menopause will shift considerably, depending on the individual age-specific AMH level. CONCLUSIONS: AMH is highly predictive for timing of menopause. Using age and AMH, the age range in which menopause will subsequently occur can be individually calculated.

AMH and AFC as predictors of excessive response in controlled ovarian hyperstimulation: a meta-analysis.

BACKGROUND: Anti-Mullerian hormone (AMH) is a marker of ovarian reserve status and represents a good predictor of ovarian response to ovarian hyperstimulation. The aim of this study was to assess the accuracy of AMH and antral follicle count (AFC) as predictors of an excessive response in IVF/ICSI treatment. METHODS: A systematic review and meta-analysis of the existing literature was performed. Studies were included if 2 × 2 tables for the outcome excessive response in IVF patients in relation to AMH/AFC could be constructed. Using a bivariate meta-analytic model, both summary point estimates for sensitivity and specificity were calculated, as well as summary ROC curves. Clinical value was analysed by calculating post-test probabilities of excessive response at optimal cut-off levels, as well as the corresponding abnormal test rates. RESULTS: Nine studies reporting on AMH and five reporting on AFC were found. Summary estimates of sensitivity and specificity for AMH were 82 and 76%, respectively, and 82 and 80%, respectively, for AFC. Comparison of the summary estimates and ROC curves for AMH and AFC showed no statistical difference. Abnormal test rates for AMH and AFC amounted to ∼14 and 16%, respectively, at cut-off levels where test performance is optimal [likelihood ratio for a positive result (LR + ) > 8], with a post-test probability of ± 70%. CONCLUSIONS: Both AMH and AFC are accurate predictors of excessive response to ovarian hyperstimulation. Moreover, both tests appear to have clinical value. This opens ways to explore the potential of individualized FSH dose regimens based on ovarian reserve testing.

Mechanism and putative structure of B(0)-like neutral amino acid transporters.

The Na(+)-dependent transport of neutral amino acids in epithelial cells and neurons is mediated by B(0)-type neutral amino acid transporters. Two B(0)-type amino acid transporters have been identified in the neurotransmitter transporter family SLC6, namely B(0)AT1 (SLC6A19) and B(0)AT2 (SLC6A15). In contrast to other members of this family, B(0)-like transporters are chloride-independent. B(0)AT1 and B(0)AT2 preferentially bind the substrate prior to the Na(+)-ion. The Na(+)-concentration affects the K ( m ) of the substrate and vice versa. A kinetic scheme is proposed that is consistent with the experimental data. An overlapping binding site of substrate and cosubstrate has been demonstrated in the bacterial orthologue LeuT( Aa ) from Aquifex aeolicus, which elegantly explains the mutual effect of substrate and cosubstrate on each other's K ( m )-value. LeuT( Aa ) is sequence-related to transporters of the SLC6 family, allowing homology modeling of B(0)-like transporters along its structure.

Plasmodium permeomics: membrane transport proteins in the malaria parasite.

Membrane transport proteins are integral membrane proteins that mediate the passage across the membrane bilayer of specific molecules and/or ions. Such proteins serve a diverse range of physiological roles, mediating the uptake of nutrients into cells, the removal of metabolic wastes and xenobiotics (including drugs), and the generation and maintenance of transmembrane electrochemical gradients. In this chapter we review the present state of knowledge of the membrane transport mechanisms underlying the cell physiology of the intraerythrocytic malaria parasite and its host cell, considering in particular physiological measurements on the parasite and parasitized erythrocyte, the annotation of transport proteins in the Plasmodium genome, and molecular methods used to analyze transport protein function.

Neutral amino acid transport in epithelial cells and its malfunction in Hartnup disorder.

Hartnup disorder is an autosomal recessive abnormality of renal and gastrointestinal neutral amino acid transport. A corresponding transport activity has been characterized in kidney and intestinal cells and named system B(0). The failure to resorb amino acids in this disorder is thought to be compensated by a protein-rich diet. However, in combination with a poor diet and other factors, more severe symptoms can develop in Hartnup patients, including a photosensitive pellagra-like skin rash, cerebellar ataxia and other neurological symptoms. Homozygosity mapping in a Japanese family and linkage analysis on six Australian pedigrees placed the Hartnup disorder gene at a locus on chromosome 5p15. This fine mapping facilitated a candidate gene approach within the interval, which resulted in the cloning and characterization of a novel member of the sodium-dependent neurotransmitter transporter family (B(0)AT1, SLC6A19) from mouse and human kidney, which shows all properties of system B(0). Flux experiments and electrophysiological recording showed that the transporter is Na(+) dependent and Cl(-) independent, electrogenic and actively transports most neutral amino acids. In situ hybridization showed strong expression in intestinal villi and in the proximal tubule of the kidney. Expression of B(0)AT1 was restricted to kidney, intestine and skin. A total of ten mutations have been identified in SLC6A19 that co-segregate with disease in the predicted recessive manner, with the majority of affected individuals being compound heterozygotes. These mutations lead to altered neutral amino acid transport function compared to the wild-type allele in vitro. One of the mutations occurs in members of the original Hartnup family described in 1956, thereby defining SLC6A19 as the 'Hartnup'-gene.

The serine/threonine kinases SGK2 and SGK3 are potent stimulators of the epithelial Na+ channel alpha,beta,gamma-ENaC.

The serum- and glucocorticoid-inducible kinase 1 (SGK1) has been identified as a signalling molecule up-regulated by aldosterone, which stimulates the renal epithelial Na(+) channel ENaC. It is therefore thought to participate in the antinatriuretic action of this hormone. More recently, two isoforms, SGK2 and SGK3, have been cloned. The present study was performed to establish whether SGK2 and SGK3 influence ENaC activity similarly to SGK1. Dual-electrode voltage-clamp experiments in Xenopus laevis oocytes expressing alpha,ss,gamma-ENaC with or without SGK1, SGK2 or SGK3 revealed a stimulatory effect of all three kinases on the amiloride-sensitive current (I(Na)). To establish whether the SGK isoforms exert their effects through direct phosphorylation, we replaced the serine at the SGK consensus site of alphaENaC (alpha(S622A)ENaC) by site-directed mutagenesis. alpha(S622A),beta,gamma-ENaC was up-regulated similar to wild-type ENaC, suggesting that SGK isoforms do not act via direct phosphorylation of the transport proteins. In conclusion, SGK2 and SGK3 mimic the function of SGK1 and are likely to participate in the regulation of ENaC activity.

Cerebral localization and regulation of the cell volume-sensitive serum- and glucocorticoid-dependent kinase SGK1.

The serum- and glucocorticoid-dependent kinase SGK1 is regulated by alterations of cell volume, whereby cell shrinkage increases and cell swelling decreases the transcription, expression and activity of SGK1. The kinase is expressed in all human tissues studied including the brain. The present study was performed to localize the sites of SGK1 transcription in the brain, to elucidate the influence of the hydration status on SGK1 transcription and to explore the functional significance of altered SGK1 expression. Northern blot analysis of human brain showed SGK1 to be expressed in all cerebral structures examined: amygdala, caudate nucleus, corpus callosum, hippocampus, substantia nigra, subthalamic nucleus and thalamus. In situ hybridization and immunohistochemistry in the rat revealed increased expression of SGK1 in neurons of the hippocampal area CA3 after dehydration, compared with similar slices from brains of euvolaemic rats. Additionally, several oligodendrocytes, a few microglial cells, but no astrocytes, were positive for SGK1. The abundance of SGK1 mRNA in the temporal lobe, including hippocampus, was increased by dehydration and SGK1 transcription in neuroblastoma cells was stimulated by an increase of extracellular osmolarity. Co-expression studies in Xenopus laevis oocytes revealed that SGK1 markedly increased the activity of the neuronal K+ channel Kv1.3. As activation of K+ channels modifies excitation of neuronal cells, SGK1 may participate in the regulation of neuronal excitability.