Gábor Mezei

Anorectic estrogen mimics leptin's effect on the rewiring of melanocortin cells and Stat3 signaling in obese animals

Metabolic hormones, such as leptin, alter the input organization of hypothalamic circuits, resulting in increased pro-opiomelanocortin (POMC) tone, followed by decreased food intake and adiposity. The gonadal steroid estradiol can also reduce appetite and adiposity, and it influences synaptic plasticity. Here we report that estradiol (E2) triggers a robust increase in the number of excitatory inputs to POMC neurons in the arcuate nucleus of wild-type rats and mice. This rearrangement of synapses in the arcuate nucleus is leptin independent because it also occurred in leptin-deficient (ob/ob) and leptin receptor–deficient (db/db) mice, and was paralleled by decreased food intake and body weight gain as well as increased energy expenditure. However, estrogen-induced decrease in body weight was dependent on Stat3 activation in the brain. These observations support the notion that synaptic plasticity of arcuate nucleus feeding circuits is an inherent element in body weight regulation and offer alternative approaches to reducing adiposity under conditions of failed leptin receptor signaling.

Factors Influencing Parental Decision Making in Prenatal Diagnosis of Sex Chromosome Aneuploidy

OBJECTIVE: To evaluate factors influencing parental decisions toward continuing or terminating a pregnancy with prenatal diagnosis of sex chromosome aneuploidy. METHODS: We reviewed the records of patients with fetuses with sex chromosome aneuploidy between 1990 and 2001. A questionnaire survey of women who chose to terminate such pregnancies was designed to examine aspects of their decision-making process. RESULTS: Forty-nine of 89 pregnancies with sex chromosome aneuploidy were terminated (termination rate 0.55; 95% confidence interval 0.45–0.65). Pregnancies with abnormal ultrasound findings (14/16, 87%), with 45,X or 47,XXY karyotypes (26/36, 72%), and with nonmosaic karyotypes (30/48, 63%) were terminated significantly more often than pregnancies with normal ultrasound findings (35/73, 48%; P < .01), with 47,XXX or 47,XYY karyotypes (4/12, 33%; P < .05), and with mosaic karyotypes (5/25, 20%; P = .01). There was a trend (P = .136) toward a lower rate of termination from 67% to 36% across time, with a significant decrease from 67% to 7% in pregnancies with 47,XXX; 47,XYY; and mosaic karyotypes (P < .01), and no change in cases with 45,X and 47,XXY karyotypes (67% compared with 69%; P = 1.0). Abnormal sexual development and infertility were the greatest parental concerns related to termination. CONCLUSION: Fear of having a child with abnormal sexual development or infertility remains the major determinant of parental decision toward terminating pregnancy, resulting in consistently high termination rates across time in pregnancies with 45,X and 47,XXY karyotypes. In cases with 47,XXX; 47,XYY; and mosaic karyotypes, the declining termination rate across time is a consequence of recent studies reporting normal sexual development and fertility. LEVEL OF EVIDENCE: II-2

Prenatal diagnosis of Turner syndrome: report on 69 cases.

Objective. This study was conducted to evaluate the diagnostic value of different sonographic signs of fetuses with Turner syndrome in the first and second trimesters of pregnancy. Methods. Between 1990 and 2004, Turner syndrome was found in 69 of 22,150 fetal karyotypings. Congenital anomalies detected by sonography were analyzed. Results. Of the 514 (2.3%; 514/22,150) chromosome aberrations that were diagnosed, 69 Turner syndrome cases were found (13.4%; 69/514). Twenty‐four fetuses had a 45,X karyotype (34.8%), and 45 fetuses were mosaic (65.2%). Forty‐seven fetuses (68.1%; 47/69) showed symptoms on sonography. A substantial proportion of fetuses with Turner syndrome showed early‐onset signs that could be detected in the first trimester (29.8%;14/69). The most common findings with sonography were hygroma colli (26.1%; 18/69), fetal hydrops (11.6%; 8/69), cardiac defects (13%; 9/69), and increased nuchal translucency (13%; 9/69). Among heart defects, coarctation of the aorta was the most common (44.4% of all cardial defects). Soft markers were also detected with relatively high frequency (23.2%; 16/69). Conclusions. The diagnosis of severe Turner syndrome is possible in early pregnancy. A search for soft markers during second‐trimester sonography and extensive use of echocardiography may increase the detection rate of Turner syndrome.

Estradiol enhances light-induced expression of transcription factors in the SCN

The suprachiasmatic nucleus of the hypothalamus (SCN) is the master clock that regulates circadian and seasonal rhythms. Among these, the SCN regulates the phasic release of hormones and provides for the timing of the preovulatory luteinizing hormone (LH) surge necessary for ovulation in females. There is little evidence, however, of sex hormone effects on mechanisms underlying SCN function. This study examined the effects of exogenous administration of estradiol on the light-induced expression of transcription factors in the SCN of female rats. Ovariectomized (OVX) female rats were given estradiol or cholesterol implants and perfused 48 h later. Half of the animals were sacrificed 1 h after the regular onset of light within the colony. The rest had the lights go on 2 h prior to the regular time and perfused 1 h later. Collected brains were sliced and sets of SCN sections were processed for immunoreactivity (ir) detecting the Fos, pCREB, egr-1, CREB binding protein (CBP), and calbindin-D (28K) proteins. Following quantification, statistical analyses demonstrated that estradiol enhanced Fos and p-CREB-ir in the SCN of females that experienced a 2-h phase advance. The phase advance also enhanced calbindin and egr-1-ir, but the expression of these proteins was not affected by estradiol. These results demonstrate that estradiol enhances the levels of transcription factors that precede the expression of clock gene proteins in the SCN in response to advances in the onset of environmental light. These data support the hypothesis that steroid hormones play an important role in the fine tuning of the clock in the face of environmental changes in daylight.

Estrogen enhances light-induced activation of dorsal raphe serotonergic neurons

The serotonergic system has been implicated in the modulation of physiological processes including circadian rhythms, learning, memory, mood and food intake. In females, cessation of ovarian function produces deleterious changes in all of these processes and estrogen treatment often ameliorates these conditions. Estrogen may produce these effects by acting on the midbrain raphe, an estrogen‐sensitive region that receives direct projections from sensory systems. Here we examined the ability of estradiol to modulate neuronal responses of neurons within raphe nuclei to photic stimulation. Ovariectomized rats treated with estradiol or cholesterol were killed 1u2003h after the normal onset of light (Zeitgeber time 0) or after a 2‐h phase advance (Zeitgeber time 22). In a second study, estradiol‐treated ovariectomized rats under constant dark conditions were exposed to light 2u2003h before the subjective onset of circadian time [(CT)22] and killed 1u2003h later (CT23). The brains from all animals were processed for Fos and/or serotonin (5‐HT) immunocytochemistry. Comparisons showed that the phase shift increased Fos immunoreactivity in all dorsal raphe nucleus (DRN) regions. Although estradiol did not alter the overall number of Fos‐positive nuclei, it significantly increased the number of Fos/5‐HT double‐labelled cells in the medial and lateral DRN. In contrast, neither a phase shift nor estradiol altered the number of Fos‐immunoreactive cells or the proportion of Fos‐positive 5‐HT cells in the median raphe nucleus. Results reveal that the DRN 5‐HT system responds to changes in the lightu2003:u2003dark cycle and that these responses are modulated by estrogen.

Chorionic Villus Sampling: A 15-Year Experience

The authors describe experiences gained over the period of 1984–1999 at two medical centers with chorionic villus sampling (CVS). Altogether 1,149 CVSs had been performed between the 10th and 32nd gestational weeks. Prior to 1993 the transcervical approach (TC-CVS), after 1994 the transabdominal method (TA-CVS) was used. Analysis of data collected within the framework of this study was based on the following factors: indications for sampling, complications and incidence of pregnancy loss. 91.6% of the CVSs were carried out for the purposes of cytogenetic examination of the fetus. Over the past few years an increasing number of procedures had been carried out for molecular-genetic tests (7.6% of the total number of cases). Though the primary indication for cytogenetic tests was the advanced age of the mother, a remarkable increase in the number of samplings had taken place for the purpose of examining ‘suspicious ultrasound findings’, minor anomalies detected by ultrasound. In this group the proportion of pathological cases was significantly higher (14%) than in all the other samplings, carried out for other indications. This data in itself underlines the importance of ultrasound screening performed in the 18–20th weeks of gestation. Over the first half of the period being reviewed (1984–1993, TC-CVS), a fetal loss of 4.8% occurring within 3 weeks from the date of sampling, dropped to 1.7% in the period subsequent to year 1994 (TA-CVS). In cases of TA-CSV, both the complications and spontaneous abortions were fewer. In 74.1% of the cases studied, birth had taken place after the 37th week of gestation. Premature births (6.4%) and stillbirth rate (1.1%) did not exceed normal rates observed in the general population. On the basis of our results, it is safe to say that in prenatal diagnosis, TA-CVS is a real alternative method of mid-trimester amniocentesis and it is recommended for use at any stage of the pregnancy.

Sex differences in adult suprachiasmatic nucleus neurons emerging late prenatally in rats

The suprachiasmatic nucleus (SCN) is implicated in the control of circadian rhythms of gonadal function. Although several structures surrounding the SCN are sensitive to the effects of gonadal steroids, similar effects in the SCN remain unclear. For example, there are conflicting data on whether the SCN is sexually differentiated. This study attempted to determine sex differences in the number of SCN cells generated during late gestation, and if testosterone mediates these differences. Pregnant female rats were treated with 5‐bromo‐2′‐deoxyuridine (BrdU; 50u2003mg/kg) on gestational day 18 (E18), the day when aromatase activity peaks in the developing rat fetus. These animals were also given injections of oil or testosterone propionate (10u2003mg/0.1u2003mL peanut oil) from E15 until parturition. Litters were allowed to survive until adulthood and were killed on postnatal day 60 (PN60). Following fixation, brain sections containing the SCN from these rats were processed for BrdU immunocytochemistry. A second set of SCN sections was processed for immunocytochemistry detecting BrdU and some of the cell groups prevalent within the SCN. Data showed that female rats have a higher number of cells labeled with BrdU in the SCN, particularly in the medial and caudal SCN. This sex difference was abolished in animals treated with testosterone during late gestation. Double immunocytochemistry revealed that BrdU‐labeled cells were neurons expressing calbindin‐D28K, vasoactive intestinal peptide and, to a lesser degree, vasopressin. Our results unveiled a previously unknown effect of gonadal steroids on the developing SCN, which may contribute to the emergence of gender‐specific circadian rhythms.

Gonadotropin-releasing hormone fibers contact POMC neurons in the hypothalamic arcuate nucleus.

The metabolic state has long been shown to affect reproduction. Peripheral signals and hormones from the reproductive organs are also known to regulate energy metabolism and feeding and energy expenditure. Much attention has been paid to determine the signaling flow from key hypothalamic neuronal populations, including those producing the anorexigenic proopiomelanocortin (POMC) derivate, α-melanocyte stimulating hormone (α-MSH), to the medial preoptic area gonadotropin-releasing hormone (GnRH) neurons, cells that are the drivers of ovulation and reproduction in general. In this study, the authors explored whether a reverse signaling modality may also exist. Specifically, the authors analyzed GnRH efferents in the arcuate nucleus with particular emphasis on their anatomical proximity to arcuate nucleus melanocortin perikarya. Using correlated light and electron microscopy, the authors observed direct apposition between GnRH-containing axon terminals and POMC cell bodies. These data provide the first experimental evidence to suggest that GnRH may have a direct influence on feeding, energy expenditure, and glucose homeostasis, independent of the activity of the gonadal axis.

[Craniospinal malformations in a twelve-year fetopathological study; the efficiency of ultrasonography in view of fetopathological investigations].

Background: Craniospinal malformations represent a heterogeneous group of congenital malformations by their morphology and etiology alike. Certain craniospinal malformations could be diagnosed as early as the dawn of ultrasonography and this group of malformations has been the focus of attention ever since. Aims: The aim of theauthors was to review the main characteristics ofcraniospinal malformations, as well as to evaluate the efficiency of ultrasonography based on autopsy examinations during twelve years. Study design: The current study comprises the details of 339 pregnancies terminated by induced abortion for craniospinal malformation between 1995 and 2006. Results: Maternal median age was 27±5.8 years, ranging from 15 to 47 years. In 24.5% of the cases, there was a positive obsterical–gynecological or genetic history. In 68.1% of the cases, ultrasonographic and autopsy findings were completely identical; in 24.2% a partial coincidence was found, but autopsy allowed for further diagnoses, while in 26 cases (7.7%) different findings wereobtained byprenatal ultrasonographyand fetopathologicalinvestigations.Inhalfof thelatter 26 cases, induced abortion was suggested due to hydrocephalus confirmed by ultrasonography but notjustifiedbyautopsyortheautopsyrevealedthepresenceofothercraniospinalmalformation(s).

Craniospinalis malformatiók 12 év foetopathologiai vizsgálatainak anyagában; az ultrahang-diagnosztika hatékonysága a foetopathologiai vizsgálatok tükrében

Background: Craniospinal malformations represent a heterogeneous group of congenital malformations by their morphology and etiology alike. Certain craniospinal malformations could be diagnosed as early as the dawn of ultrasonography and this group of malformations has been the focus of attention ever since. Aims: The aim of theauthors was to review the main characteristics ofcraniospinal malformations, as well as to evaluate the efficiency of ultrasonography based on autopsy examinations during twelve years. Study design: The current study comprises the details of 339 pregnancies terminated by induced abortion for craniospinal malformation between 1995 and 2006. Results: Maternal median age was 27±5.8 years, ranging from 15 to 47 years. In 24.5% of the cases, there was a positive obsterical–gynecological or genetic history. In 68.1% of the cases, ultrasonographic and autopsy findings were completely identical; in 24.2% a partial coincidence was found, but autopsy allowed for further diagnoses, while in 26 cases (7.7%) different findings wereobtained byprenatal ultrasonographyand fetopathologicalinvestigations.Inhalfof thelatter 26 cases, induced abortion was suggested due to hydrocephalus confirmed by ultrasonography but notjustifiedbyautopsyortheautopsyrevealedthepresenceofothercraniospinalmalformation(s).